JP7656901B2 - Ship performance estimation method, performance estimation program, and performance estimation system - Google Patents

Description

The present invention relates to a ship performance estimation method, a performance estimation program, and a performance estimation system that estimate the performance of a ship using tank tests and CFD (computational fluid dynamics) calculations.

Ship performance predictions are based on tank tests using models similar to the actual ship. Recent advances in numerical calculation technology have made it possible to perform performance calculations using CFD, but we have not yet reached a level where performance predictions can be made using CFD alone.

Here, Patent Document 1 discloses a method for estimating ship performance using data assimilation, which uses at least one of model ship data measured using a model ship and actual ship data measured on the actual ship in the computational fluid dynamics (CFD) calculations to estimate the performance of a ship, and assimilates the data into the computational fluid dynamics (CFD) calculations to improve the accuracy of ship performance estimation in the computational fluid dynamics (CFD) calculations.
Furthermore, Patent Document 2 discloses an LNG ship that is equipped with multiple ballast tanks arranged along the longitudinal direction of the hull and that adjust the ship's attitude including the trim and draft of the hull, an injection and discharge device that injects water into and discharges water from each ballast tank, and an injection and discharge control unit that controls the injection and discharge operation of the injection and discharge device, in which the injection and discharge control unit is equipped with a fuel consumption reduction mode that operates the injection and discharge devices so as to assume an attitude that reduces the horsepower required by the main engine in accordance with the sailing conditions while sailing.
Patent document 3 also discloses a ship management device that includes first navigation conditions indicating the navigation conditions of the ship including at least the basic conditions related to the navigation of the ship and the inclination of the ship, an acquisition means for acquiring first data indicating the navigation performance of the ship corresponding to the first navigation conditions, an identification means for identifying a navigation performance associated with the first navigation condition whose basic conditions match a specified navigation condition based on the first data, and an output means for outputting the first navigation condition corresponding to a higher navigation performance among the navigation performances identified by the identification means as second data.
Furthermore, Patent Document 4 discloses a simulation program that causes a computer that simulates a system to be analyzed to perform a reduced-order simulation that expresses the system using a linear sum that is the sum of products of basis vectors, the number of which is less than a predetermined degree of freedom, extracted as characteristic quantities of the system based on the results of a simulation of the system with a predetermined degree of freedom, and weighting coefficients corresponding to each basis vector, and performs a data assimilation process that determines, periodically or irregularly during the execution of the reduced-order simulation, weighting coefficients that minimize a first error between measurement data in the system and the results of the reduced-order simulation as weighting coefficients in the linear sum.

JP 2020-158072 A JP 2009-184378 A JP 2015-83468 A JP 2014-26440 A

Patent Documents 2 to 4 do not aim to improve the accuracy of ship performance estimation by data assimilation of tank tests and CFD calculations.
Patent Document 1 relates to improving the accuracy of ship performance estimation in computational fluid dynamics (CFD) calculations by assimilating model ship data or actual ship data into the computational fluid dynamics (CFD) calculations, but there is a demand for further improvement in the accuracy of ship performance estimation by effectively utilizing the results of tank tests and CFD calculations.
Therefore, an object of the present invention is to provide a ship performance estimation method, a performance estimation program, and a performance estimation system that are capable of accurately estimating the performance of a ship.

A ship performance estimation method corresponding to the method described in claim 1 is a performance estimation method in which the performance of a ship is estimated by a computer using tank tests and CFD (computational fluid dynamics) calculations, and is characterized in having a hull condition acquisition step in which the computer acquires the hull conditions of the ship, an operating condition acquisition step in which the computer acquires the operating conditions of the ship, a tank test step in which the computer uses a model ship of the ship to conduct a tank test based on the hull conditions and the operating conditions and the computer uses the results of the tank test to determine the resistance coefficient and self-propulsion element of the ship, a CFD calculation step in which the computer conducts CFD calculations based on the hull conditions and the operating conditions and determines the resistance coefficient and self-propulsion element of the ship, and a resistance coefficient and self-propulsion element correction step in which the computer determines the difference between the resistance coefficient and the self-propulsion element obtained by the tank test and the CFD calculation, corrects the difference based on the set number of variables of the operating conditions in the tank test, and obtains corrected values for the resistance coefficient and self-propulsion element.
According to the present invention described in claim 1, the performance of a ship can be accurately estimated by obtaining correction values for the resistance coefficient and self-propulsion elements using the results of tank tests and CFD calculations derived under the same hull conditions and operating conditions.

In the present invention as set forth in claim 2, the operating conditions are at least one of the ship's speed, trim, draft, weather and sea conditions.
According to the present invention described in claim 2, by using operating conditions that have a large impact on the operation of a ship, the accuracy of estimating the performance of the ship involved in operation can be improved, leading to optimal operation.

The present invention as described in claim 3 is characterized in that the resistance coefficient is the wave-making resistance coefficient, the shape influence coefficient, and the resistance increase coefficient in waves, and the self-propulsion elements are the thrust reduction coefficient, the effective wake coefficient, and the propeller efficiency ratio.
According to the present invention as defined in claim 3, it is possible to improve the accuracy of the resistance coefficient and self-propulsion elements, which are important in estimating the performance related to the operation of a ship.

The present invention as set forth in claim 4 is characterized in that, when the number of variables set is one, the computer determines the correction value by performing linear interpolation based on equation (1).
According to the present invention as set forth in claim 4, when the number of variables set for the operational conditions is one, the correction value can be obtained with high accuracy.

The present invention as set forth in claim 5 is characterized in that, when the number of variables set is two, the computer performs linear interpolation based on equation (2) to determine the correction value.
According to the present invention as set forth in claim 5, when the number of variables of the operational conditions is two, the correction value can be obtained with high accuracy.

In the present invention, when the number of variables set is three, the computer performs linear interpolation based on the formula (3) to determine the correction value.
According to the present invention as set forth in claim 6, when the number of variables of the operational conditions is three, the correction value can be obtained with high accuracy.

The present invention as described in claim 7 is a performance estimation method for estimating ship performance by a computer using a ship performance estimation method, characterized in that it has a hull resistance derivation step in which the computer derives the relationship between the ship speed and hull resistance based on the resistance coefficient and the corrected value of the resistance coefficient obtained in the self-propulsion element correction step.
According to the seventh aspect of the present invention, the relationship between the ship speed and the hull resistance can be derived with high accuracy based on the corrected resistance coefficient.

The present invention as defined in claim 8 is characterized in that it further comprises a driving force derivation step in which the computer derives the relationship between the speed and driving force of the vessel based on the correction value of the self-propulsion element.
According to the eighth aspect of the present invention, the relationship between the ship's speed and driving force can be derived with high accuracy based on the corrected self-propulsion elements.

The present invention as described in claim 9 is characterized in that it further includes a horsepower derivation step in which the computer derives the relationship between the ship's speed and horsepower based on the relationship between speed and hull resistance derived in the hull resistance derivation step and the relationship between speed and driving force derived in the driving force derivation step.
According to the ninth aspect of the present invention, the relationship between the speed and the horsepower of a boat can be estimated with high accuracy.

The present invention as defined in claim 10 is characterized in that the relationship between speed and horsepower takes into consideration the trim and draft of the ship.
According to the present invention as set forth in claim 10, the relationship between speed and horsepower taking into account the trim and draft of the ship can be accurately estimated, making it possible to use this information in the actual operation of the ship.

The present invention according to claim 11 is characterized in that it further comprises a fuel consumption amount deriving step in which a computer determines the fuel consumption amount of the ship for each speed and trim of the ship based on the horsepower.
According to the present invention as set forth in claim 11, it is possible to grasp the fuel consumption for each speed and trim of the ship, and this can be directly utilized for the actual operation of the ship.

The present invention as set forth in claim 12 is characterized in that it further comprises a charting step in which the computer charts the relationship between the speed, trim, and fuel consumption of the vessel.
According to the twelfth aspect of the present invention, for example, a chart of the relationship between the speed, trim and fuel consumption of a ship in calm water can be obtained.

The present invention as described in claim 13 is characterized in that it further includes an actual sea area charting step in which the computer obtains an actual sea area chart by taking into account weather and sea conditions and adding changes in the ship's speed, trim, and fuel consumption in the actual sea area to the chart obtained in the charting step.
According to the present invention as set forth in claim 13, for example, the speed and trim of the ship can be adjusted based on the obtained actual sea area chart, and optimal speed allocation navigation and trim navigation can be performed in the actual sea area.

The present invention as set forth in claim 14 is characterized in that it further comprises a correction step in which the computer corrects the actual sea area chart taking into account operation data of the ship in the actual sea area.
According to the present invention as set forth in claim 14, the actual sea area chart can be corrected and updated based on operation data in the actual sea area.

The present invention as set forth in claim 15 is characterized by further comprising a replacement step in which the computer replaces the actual sea area chart taking into consideration observation data of weather and sea conditions that the ship will encounter in the actual sea area.
According to the fifteenth aspect of the present invention, by replacing the chart with an optimum actual sea area chart taking into account the observation data, it is possible to operate with more appropriate speed distribution and trim.

The present invention as set forth in claim 16 is characterized in that it further comprises an automatic trim adjustment step in which the computer takes into account the loading information of the ship and automatically adjusts the trim of the ship according to the actual sea area chart.
According to the present invention as set forth in claim 16, the ship can be automatically adjusted to an optimal trim, thereby enabling operation with optimal trim.

A ship performance estimation program corresponding to the seventeenth aspect of the present invention is a performance estimation program for estimating ship performance using a ship performance estimation method, and is characterized in that it causes a computer to execute a correction value acquisition step for acquiring a corrected resistance coefficient and a correction value for a self-propulsion element, a condition acquisition step for acquiring at least the input speed and trim, a hull resistance derivation step, a driving force derivation step, a horsepower derivation step, a fuel consumption derivation step, and an output step for outputting the derivation result of at least the fuel consumption.
According to the seventeenth aspect of the present invention, for example, fuel consumption for each speed and trim of a ship can be obtained quickly and highly accurately using a computer.

The present invention as defined in claim 18 is characterized in that the computer is further made to execute a charting step.
According to the eighteenth aspect of the present invention, a chart showing the relationship between the speed, trim and fuel consumption of a ship in calm water, for example, can be obtained quickly and highly accurately using a computer.

The present invention as defined in claim 19 is characterized in that the computer is further made to execute a step of charting an actual sea area.
According to the nineteenth aspect of the present invention, an actual sea area chart can be obtained quickly and highly accurately using a computer, and, for example, optimal speed allocation navigation and trim navigation can be performed in actual sea areas.

A ship performance estimation system corresponding to the claim 20 is a performance estimation system that estimates the performance of a ship using tank tests and CFD (computational fluid dynamics) calculations, and is characterized in that it has a hull condition acquisition means for acquiring the hull conditions of the ship, an operating condition acquisition means for acquiring the operating conditions of the ship, a tank test means for performing a tank test based on the hull conditions and the operating conditions using a model of the ship, and obtaining the resistance coefficient and self-propulsion element of the ship, a CFD calculation means for performing a CFD calculation based on the hull conditions and the operating conditions, and obtaining the resistance coefficient and self-propulsion element of the ship, and a resistance coefficient and self-propulsion element correction means for determining the difference between the resistance coefficient and the self-propulsion element obtained by the tank test and the CFD calculation, correcting the difference based on the set number of variables of the operating conditions in the tank test, and obtaining corrected values for the resistance coefficient and self-propulsion element.
According to the present invention as set forth in claim 20, the performance of a ship can be accurately estimated by obtaining correction values for the resistance coefficient and self-propulsion elements using the results of tank tests and CFD calculations derived under the same hull conditions and operating conditions.

The present invention according to claim 21 is characterized in that the tank testing means is an automated tank testing means which automatically performs tests using a model ship and determines the resistance coefficient and the self-propulsion parameters.
According to the twenty-first aspect of the present invention, the resistance coefficient and self-propulsion parameters can be obtained by performing tank testing with reduced manpower or without manpower.

The present invention as recited in claim 22 is characterized in that it comprises an automatic ship model manufacturing means, and the automatic manufacturing means manufactures the model ship based on the acquired hull conditions.
According to the present invention as set forth in claim 22, the model ship is automatically produced based on the acquired hull conditions, thereby shortening the number of days required to produce the model ship, thereby enabling tank testing to begin earlier and the resistance coefficient and self-propulsion elements of the ship to be determined earlier.

A ship performance estimation system corresponding to the twenty-third aspect of the present invention is a performance estimation system for estimating ship performance, comprising a computer, an input means for the computer, and an output means for the computer, and is characterized in that the system causes the computer to execute a ship performance estimation program.
According to the twenty-third aspect of the present invention, the relationship between speed, trim, and fuel consumption, for example, can be obtained by utilizing the results of a high-speed and high-precision estimation of ship performance using a computer.

The present invention as set forth in claim 24 is characterized in that the ship is automatically operated based on an output from the output means.
According to the twenty-fourth aspect of the present invention, for example, efficient automatic operation can be realized in which optimum speed distribution and optimum trim adjustment are automatically performed when operating a ship.

In the ship performance estimation system according to claim 25, the ship performance estimation system is connected via an information and communication network to estimate the ship performance.
According to the present invention described in claim 25, even if each component of the ship performance estimation system is installed in a remote location, the components can work together via an information and communication network to estimate the ship performance.

According to the ship performance estimation method of the present invention, the results of tank tests and CFD calculations derived under the same hull conditions and operating conditions are used to obtain correction values for the resistance coefficient and self-propulsion elements, making it possible to accurately estimate the ship's performance.

In addition, when the operating conditions are at least one of the ship's speed, trim, draft, weather, and sea conditions, using the operating conditions that have the greatest impact on the ship's operation can improve the accuracy of the ship's performance estimation related to operation, leading to optimal operation.

In addition, if the resistance coefficients are the wave-making resistance coefficient, shape influence coefficient, and wave resistance increase coefficient, and the self-propulsion elements are the thrust reduction coefficient, effective wake coefficient, and propeller efficiency ratio, it is possible to improve the accuracy of the resistance coefficient and self-propulsion elements, which are important in estimating the performance related to the operation of a ship.

In addition, when the computer determines the correction value by performing linear interpolation based on equation (1) when the number of variables set is one, the correction value can be determined with high accuracy when the number of variables set for the operational conditions is one.

In addition, when the computer determines the correction value by performing linear interpolation based on equation (2) when the number of variables set is two, the correction value can be determined with high accuracy when the number of variables set for the operational conditions is two.

In addition, when the computer determines the correction value by performing linear interpolation based on equation (3) when the number of variables set is three, the correction value can be determined with high accuracy when the number of variables set for the operating conditions is three.

In addition, the ship performance estimation method of the present invention is a performance estimation method in which ship performance is estimated by a computer , and when the computer has a hull resistance derivation step in which it derives the relationship between the ship's speed and hull resistance based on the resistance coefficient and the corrected value of the corrected resistance coefficient obtained in the self-propulsion element correction step, it is possible to accurately derive the relationship between the ship's speed and hull resistance based on the corrected resistance coefficient.

In addition, if the computer further has a driving force derivation step of deriving the relationship between the ship's speed and driving force based on the corrected value of the self-propulsion element, the relationship between the ship's speed and driving force can be accurately derived based on the corrected self-propulsion element.

In addition, if the computer further has a horsepower derivation step of deriving the relationship between the ship's speed and horsepower based on the relationship between speed and hull resistance derived in the hull resistance derivation step and the relationship between speed and driving force derived in the driving force derivation step, the relationship between the ship's speed and horsepower can be accurately estimated.

In addition, if the relationship between speed and horsepower takes into account the trim and draft of the ship, the relationship between speed and horsepower taking into account the trim and draft of the ship can be accurately estimated, making it possible to use this information in the actual operation of the ship.

In addition, if the computer has a fuel consumption derivation step for calculating the fuel consumption of the ship for each ship speed and trim based on horsepower, the fuel consumption of the ship for each ship speed and trim can be grasped, which can be directly useful for the actual operation of the ship.

Furthermore, if the computer further includes a charting step of charting the relationship between the vessel's speed, trim, and fuel consumption, a chart of the relationship between the vessel's speed, trim, and fuel consumption in calm water, for example, can be obtained.

In addition, if the computer further has an actual sea area charting step in which the chart obtained in the charting step is added with consideration of weather and sea conditions to obtain an actual sea area chart that includes changes in the ship's speed, trim, and fuel consumption in actual sea areas, then, for example, the ship's speed and trim can be adjusted based on the obtained actual sea area chart, and optimal speed allocation and trim operation can be performed in actual sea areas.

In addition, if the computer further has a correction step of taking into account the ship's operation data in the actual sea area and correcting the actual sea area chart, the actual sea area chart can be corrected and updated based on the operation data in the actual sea area.

In addition, if the computer further has a replacement step of replacing the actual sea area chart taking into account observation data on weather and sea conditions that the ship will encounter in its actual sea area, the ship can operate with more appropriate speed distribution and trim by replacing the actual sea area chart with the most appropriate one taking into account the observation data.

In addition, if the computer further has an automatic trim adjustment step that takes into account the ship's loading information and automatically adjusts the ship's trim in accordance with the actual sea area chart, optimal trim operation is possible by automatically adjusting the ship to the optimal trim.

In addition, the ship performance estimation program of the present invention can use a computer to quickly and accurately obtain, for example, fuel consumption for each ship speed and trim.

In addition, if the computer is further made to perform a charting step, the computer can be used to quickly and accurately obtain a chart of, for example, the relationship between a vessel's speed, trim, and fuel consumption in calm water.

In addition, if the computer is further made to execute the step of charting the actual sea area, the computer can be used to obtain an actual sea area chart quickly and with high accuracy, enabling, for example, optimal speed allocation and trim navigation in the actual sea area.

In addition, the ship performance estimation system of the present invention can accurately estimate the ship's performance by obtaining correction values for the resistance coefficient and self-propulsion elements using the results of tank tests and CFD calculations derived under the same hull conditions and operating conditions.

In addition, if the tank test means is an automated tank test means that automatically performs tests using a model ship to determine the resistance coefficient and self-propulsion factors, the tank test can be performed with reduced manpower or unmanned to determine the resistance coefficient and self-propulsion factors.

In addition, if an automatic model ship production means is provided and the model ship is produced by the automatic production means based on the acquired hull conditions, the number of days required to produce the model ship can be shortened by automatically producing the model ship based on the acquired hull conditions, which makes it possible to start tank testing earlier and quickly determine the resistance coefficient and self-propulsion elements of the ship.

The ship performance estimation system of the present invention is a performance estimation system that estimates the performance of a ship, and includes a computer, an input means to the computer, and an output means from the computer. When the computer is caused to execute a ship performance estimation program, the results of the ship performance estimation performed at high speed and with high accuracy using the computer can be used to obtain, for example, the relationship between speed, trim, and fuel consumption.

In addition, when the ship is operated automatically based on the output from the output means, efficient automatic operation can be realized, for example, by automatically allocating optimal speed and adjusting optimal trim when operating the ship.

In addition, when the ship performance estimation system is connected via an information and communication network to estimate the ship performance, even if each component of the ship performance estimation system is installed in a remote location, the components can work together via the information and communication network to estimate the ship performance.

First flow of a ship performance estimation method according to an embodiment of the present invention A diagram showing how to calculate the correction value when the number of settings for the same variable is two. A diagram showing how to calculate the correction value when the number of settings for the same variable is three. A diagram showing an example of the trim chart The second flow of the ship's performance estimation method The third flow of the ship's performance estimation method The fourth flow of the ship's performance estimation method Diagram of the ship's performance estimation system Flow of ship performance estimation method using this system

A ship performance estimation method, a performance estimation program, and a performance estimation system according to an embodiment of the present invention will be described.
FIG. 1 shows a first flow of the ship performance estimation method according to the present embodiment.
The method for estimating the performance of a ship involves estimating the performance of the ship using tank tests and CFD (computational fluid dynamics) calculations.
First, the hull conditions of the ship are acquired (hull condition acquisition step S1). The hull conditions acquired in the hull condition acquisition step S1 are design conditions such as the hull shape, main engine information, etc.
Furthermore, the operating conditions of the ship are acquired (operating condition acquisition step S2). In the operating condition acquisition step S2, it is preferable to acquire at least one of the ship's speed (speed condition), trim and draft (draft condition), and weather and sea conditions (weather and sea conditions) as the operating conditions. By using operating conditions that have a large effect on the operation of the ship, it is possible to improve the accuracy of the ship performance estimation related to the operation, leading to optimal operation.

Next, a tank test is performed using a model ship of the ship, and the resistance coefficient and self-propulsion factors of the ship are obtained as tank test data (tank test step S3). The tank test in the tank test step S3 is performed based on the hull conditions acquired in the hull condition acquisition step S1 and the operating conditions acquired in the operating condition acquisition step S2. The obtained tank test data is stored in the tank test database 10.
In addition, a CFD calculation is performed to determine the resistance coefficient and self-propulsion factors of the ship (CFD calculation step S4). The CFD calculation in CFD calculation step S4 is performed based on the same hull conditions and operating conditions as those of the tank test. However, in the tank test, a model ship of a similar shape created based on the hull conditions is used, and the operating conditions are replaced with similar tank test conditions.
The resistance coefficients calculated in the tank test step S3 and the CFD calculation step S4 are preferably the wave resistance coefficient, the shape influence coefficient, and the wave resistance increase coefficient, and the self-propulsion factors are preferably the thrust reduction coefficient, the effective wake coefficient, and the propeller efficiency ratio. This makes it possible to improve the accuracy of the resistance coefficient and the self-propulsion factors, which are important in estimating the performance related to the operation of a ship.

Next, data assimilation (performance correction) is performed between the resistance coefficient and self-propulsion elements obtained in the tank test step S3 and the resistance coefficient and self-propulsion elements obtained in the CFD calculation step S4. When correcting the performance, an uncertainty analysis of the CFD calculation is performed.
In data assimilation, the difference between the resistance coefficient and self-propulsion elements obtained from the tank test and the CFD calculation is calculated, and the difference is corrected based on the number of variables set for the operating conditions in the tank test to obtain corrected values for the resistance coefficient and self-propulsion elements (resistance coefficient and self-propulsion element correction step S5).
By obtaining correction values for the resistance coefficient and self-propulsion elements using the results of tank tests and CFD calculations derived under the same hull conditions and operating conditions, it is possible to accurately estimate the performance of a ship.

In the resistance coefficient and self-propulsion element correction step S5, if there is not one tank test result but multiple results for speed, trim, draft, etc., the correction value C (Δwt, etc.) is found using linear interpolation.
For example, when the number of operating condition variables set in the tank test is one, such as when there are results for each speed, it is preferable to determine the correction value by linear interpolation based on the following formula (1). This makes it possible to accurately determine the correction value when the number of operating condition variables set is one.
In equation (1), C is the correction value, _C1 is the correction amount at test point 1, _C2 is the correction amount at test point 2, and _a1 is the displacement amount from test point 1.

2 is a diagram showing a method for calculating a correction value when the number of variables set is two. The numbers 1 to 4 at the vertices of the squares on the left side represent test points.
For example, when the number of operational variables set in the tank test is two, such as when there are results for each speed and draft, it is preferable to determine the correction value by linear interpolation based on the following formula (2). This makes it possible to accurately determine the correction value when the number of operational variables set is two.
In equation (2), C is the correction value, _C1 is the correction amount at test point 1, _C2 is the correction amount at test point 2, _C3 is the correction amount at test point 3, and _C4 is the correction amount at test point 4.
Furthermore, if δξ is the first variable and is the amount of displacement around the vector heading from test point 1 to test point 2, and δη is the second variable and is the amount of displacement around the vector heading from test point 1 to test point 4, then a ₁ = (1 - δξ - δη + δξδη), a ₂ = δξ(1 - δη), a ₃ = δξδη, a ₄ = δη(1 - δξ), and a ₁ + a ₂ + a ₃ + a ₄ = 1.

3 is a diagram showing a method for calculating a correction value when the number of variables set is three. The numbers 1 to 8 attached to the vertices of a cube represent test points.
For example, when the number of variables of the operating conditions in the tank test is three, such as when there are results for each of the speed, draft, and trim, it is preferable to determine the correction value by linear interpolation based on the following formula (3). This makes it possible to accurately determine the correction value when the number of variables of the operating conditions is three.
In formula (3), C is a correction value, _C1 is a correction amount at test point 1, _C2 is a correction amount at test point 2, _C3 is a correction amount at test point 3, _C4 is a correction amount at test point 4, _C5 is a correction amount at test point 5, _C6 is a correction amount at test point 6, _C7 is a correction amount at test point 7, _C8 is a correction amount at test point 8, δξ is a first variable (e.g., speed) and is a displacement amount around a vector heading from test point 1 to test point 2, δη is a second variable (e.g., draft) and is a displacement amount around a vector heading from test point 1 to test point 4, and δζ is a third variable (e.g., trim) and is a displacement amount around a vector heading from test point 1 to test point 5.

In addition, in the drag coefficient and self-propulsion element correction step S5, spline interpolation, Lagrange interpolation, or radial basis function interpolation can be used instead of linear interpolation. However, since the tank test data is treated as more positive than the CFD calculation value, the tank test data is always interpolated to the tank test value when there is tank test data. For this reason, methods that use approximation functions that do not pass through areas where data exists are not used.

1, after the resistance coefficient and self-propulsion element correction step S5, the relationship between the ship speed and hull resistance is derived based on the resistance coefficient correction value obtained in the resistance coefficient and self-propulsion element correction step S5 (hull resistance derivation step S6). This makes it possible to accurately derive the relationship between the ship speed and hull resistance based on the corrected resistance coefficient.
Furthermore, the relationship between the vessel speed and driving force is derived based on the corrected values of the own propulsion elements (driving force derivation step S7). This makes it possible to accurately derive the relationship between the vessel speed and driving force based on the corrected own propulsion elements.
Data-assimilated propulsive performance data is obtained by the hull resistance derivation step S6 and the driving force derivation step S7.

Next, data such as propeller independent performance, roughness correction coefficient, and wake model/actual ship correction coefficient are extracted from the horsepower calculation database 11. Then, based on the relationship between speed and hull resistance derived in hull resistance derivation step S6 and the relationship between speed and driving force derived in driving force derivation step S7, the relationship between ship speed and horsepower is derived (horsepower derivation step S8). This makes it possible to accurately estimate the relationship between ship speed and horsepower.
It should be noted that horsepower is referred to by various names such as braking horsepower, driving horsepower, required horsepower, shaft horsepower, and necessary horsepower, but these can all be included within the scope of the concept of the present invention.
It is preferable that the relationship between speed and horsepower derived in the horsepower derivation step S8 is a relationship that takes into account the trim and draft of the ship. For example, by deriving the relationship between speed and braking horsepower (BHP) for each torque and draft, it is possible to accurately estimate the relationship between speed and horsepower that takes into account the trim and draft of the ship, and this can be useful for the actual operation of the ship.
In addition, operation data acquired on an actual ship is extracted from the actual ship performance database 12, and the horsepower estimation results obtained in the horsepower derivation step S8, such as the overall horsepower curve and the relationship between speed and horsepower, are corrected (horsepower estimation result correction step S9). In the horsepower estimation result correction step S9, the horsepower curve under calm conditions is corrected with the operation data.

Next, the fuel consumption of the vessel for each speed and trim of the vessel is calculated based on the horsepower (fuel consumption calculation step S10). This makes it possible to grasp the fuel consumption of the vessel for each speed and trim of the vessel, which can be directly used for the actual operation of the vessel.
Also, the relationship between the vessel speed, trim, and fuel consumption is charted (charting step S11), whereby, for example, a trim chart of the relationship between the vessel speed, trim, and fuel consumption in calm water can be obtained.
The amount of fuel consumption may be referred to by various names such as fuel efficiency, fuel consumption rate, and fuel efficiency rate, but these may be included within the scope of the concept of the present invention.
Fig. 4 shows an example of a trim chart, with Fig. 4(a) being for a vessel with a draft of 7.6 m, Fig. 4(b) being for a vessel with a draft of 8.3 m, and Fig. 4(c) being for a vessel with a draft of 9.0 m. The vertical axis represents the stern trim [m], the horizontal axis represents the speed [knot], and the braking horsepower (BHP) at the corresponding speed in calm water is represented by different shades of color.
A trim chart is a chart showing the ship's speed and propulsive performance for each trim in several draft conditions. Since the draft is determined by the loading situation, the set ship speed can be determined taking into account the estimated time of arrival (ETA), and the trim that optimizes propulsive performance can be found. Note that trim charts can be created not only for calm water conditions, but also for performance in waves and wind, as described below.

In this way, the trim chart for calm water is obtained through the first flow of the ship performance estimation method. The navigator uses the obtained trim chart to adjust the trim and operate with optimal trim.

FIG. 5 shows a second flow of the ship performance estimation method.
This flow includes an actual sea area charting step S12 for taking into account weather and sea conditions and adding changes in the ship's speed, trim, and fuel consumption in the actual sea area to the chart obtained in the charting step S11 to obtain an actual sea area chart.
In the actual sea area charting step S12, actual sea area performance calculations are performed using data-assimilated calm water performance such as speed, hull resistance, propeller thrust, braking horsepower, and fuel consumption for each trim and draft obtained in the first flow of the ship performance estimation method, hull conditions, external force data such as waves and wind, and sea conditions such as Beaufort scale, to obtain an actual sea area chart (actual sea area trim chart). Loading information (draft during operation) is also obtained.
This allows the navigator to take into account loading information (draft during navigation) and adjust the ship's speed and trim, for example, based on the actual sea area chart obtained, thereby enabling navigation with optimal speed allocation and trim in actual sea areas.

FIG. 6 shows a third flow of the ship performance estimation method.
This flow includes a correction step S13 for correcting the actual sea area chart taking into account the ship's operation data in the actual sea area.
In the correction step S13, the actual ship data is analyzed and assimilated based on the actual sea area chart and loading information obtained in the second flow of the ship performance estimation method and the operation data in the actual sea area obtained from the actual sea area operation database 13. This makes it possible to correct and update the actual sea area chart based on the operation data in the actual sea area.
Navigators can adjust trim based on updated actual sea area charts and operate with optimal trim in actual sea areas.

FIG. 7 shows a fourth flow of the ship performance estimation method.
In this flow, the actual sea area chart is replaced taking into account observation data on weather and sea conditions that the ship will encounter in its actual sea area (replacement step S14), and the ship's trim is automatically adjusted in accordance with the actual sea area chart taking into account the ship's loading information (automatic trim adjustment step S15).
In replacement step S14, the sea conditions including weather are grasped based on the actual sea area chart and loading information obtained in the second flow of the ship performance estimation method and observation data on weather and sea conditions such as waves and wind obtained from the observation database 14, and the actual sea area chart is replaced with an optimal one. By replacing the actual sea area chart with an optimal one taking into account the observation data, it is possible to navigate with more appropriate speed distribution and trim based on the actual sea conditions and weather in the actual sea area.
In the automatic trim adjustment step S15, the controller controls the trim adjustment device based on the loading information and the actual sea area chart. By automatically adjusting the ship to the optimum trim according to the actual sea area chart, optimal trim navigation is possible. Automatic trim adjustment is possible by adding and removing water from the trim tank, moving cargo, controlling additional devices for trim adjustment, etc.

FIG. 8 is a configuration diagram of a ship performance estimation system, and FIG. 9 is a flow chart of a ship performance estimation method using the system.
The ship performance estimation system includes a first performance estimation system 20 that estimates the performance of the ship using tank tests and CFD (computational fluid dynamics) calculations, and a second performance estimation system 30 that estimates the performance of the ship. The first performance estimation system 20 and the second performance estimation system 30 are connected via an information and communication network 40 such as the Internet. As a result, even if each component of the ship performance estimation system is installed in a remote location, the components can cooperate with each other via the information and communication network 40 to estimate the performance of the ship.

The first performance estimation system 20 includes a hull condition acquisition means 21 that executes a hull condition acquisition step S1 to acquire the hull conditions of the ship, an operation condition acquisition means 22 that executes an operation condition acquisition step S2 to acquire the operation conditions of the ship, a tank testing means 23 that executes a tank test step S3 to obtain the resistance coefficient and self-propulsion elements of the ship, a CFD calculation means 24 that executes a CFD calculation step S4 to obtain the resistance coefficient and self-propulsion elements of the ship, a resistance coefficient and self-propulsion element correction means 25 that executes a resistance coefficient and self-propulsion element correction step S5 to obtain correction values for the resistance coefficient and self-propulsion elements, and an automatic model ship production means 26.
The tank test room A is equipped with a hull condition acquisition means 21, an operating condition acquisition means 22, a tank test means 23, and an automatic production means 26, and the CFD calculation room B is equipped with a hull condition acquisition means 21, an operating condition acquisition means 22, and a CFD calculation means 24.
In this embodiment, the resistance coefficient and self-propulsion element correction means 25 is not provided on the first performance estimation system 20 side, and the computer 31 on the second performance estimation system 30 side is given the function of the resistance coefficient and self-propulsion element correction means 25.

The tank test means 23 performs a tank test using a model ship based on the hull conditions and operating conditions, while the CFD calculation means 24 performs a CFD calculation based on the hull conditions and operating conditions.
The resistance coefficient and self-propulsion element correction means 25 executes the above-mentioned resistance coefficient and self-propulsion element correction step S5, determining the difference between the resistance coefficient and self-propulsion elements obtained from the tank test and the CFD calculation, and correcting the difference based on the number of variables set for the operating conditions in the tank test.
By obtaining correction values for the resistance coefficient and self-propulsion elements using the results of tank tests and CFD calculations derived under the same hull conditions and operating conditions, it is possible to accurately estimate the performance of a ship.

The tank test means 23 is preferably an automated tank test means that automatically performs tests using a model ship to determine the resistance coefficient and the self-propulsion factor. This makes it possible to determine the resistance coefficient and the self-propulsion factor while reducing manpower or performing the tank test unmannedly.
Moreover, the model ship used in the tank test is produced by the automatic production means 26 based on the hull conditions acquired by the hull condition acquisition means 21. By automatically producing the model ship based on the acquired hull conditions, the number of days required to produce the model ship can be shortened, which makes it possible to start the tank test early and quickly determine the resistance coefficient and self-propulsion elements of the ship.

The second performance estimation system 30 is provided in the center C, and includes a computer 31, an input means 32 to the computer 31, and an output means 33 from the computer 31. The input means 32 accepts automatic input from other systems, etc., or manual input via a mouse, keyboard, etc. The output destination of the output means 33 is the user of the information connected via the information communication network 40, or, for example, a controller, monitor, printer, etc. in the center C. The center C can also have a function of managing the entire ship performance estimation system. That is, the input means 32 in the center C inputs hull conditions and operating conditions used in tank tests and CFD calculations, receives the results of the tank tests and CFD calculations, and further causes the computer 31 to correct the resistance coefficient and self-propulsion elements and execute each step, and outputs the obtained results to the operating company D or the actual ship E via the output means.
A performance estimation program for estimating the performance of a ship is installed in the computer 31. When a step execution unit 31A of the computer 31 accepts an operation, the performance estimation program causes the computer 31 to execute a correction value acquisition step S16 for acquiring a corrected resistance coefficient and a correction value for the own propulsion element, a condition acquisition step S17 for acquiring at least the speed and trim inputted by the input means 32, a hull resistance derivation step S6, a driving force derivation step S7, a horsepower derivation step S8, a fuel consumption derivation step S10, a charting step S11, an actual sea area charting step S12, a correction step S13, a replacement step S14, and an output step S18 for outputting the derivation result of at least the fuel consumption.
By using the ship performance estimation program, charts of, for example, fuel consumption for each ship speed and trim, charts of the relationship between the ship speed, trim and fuel consumption in calm water, and actual sea area charts can be obtained quickly and with high accuracy using the computer 31. Furthermore, based on the obtained actual sea area charts, for example, optimal speed allocation navigation and trim navigation can be performed in actual sea areas.

The ship performance estimation system also automatically adjusts the ship's trim by executing an automatic trim adjustment step S15 based on the output from the output means 33, and automatically operates the ship. This makes it possible to realize efficient automatic operation in which, for example, optimal speed allocation and optimal trim adjustment for ship operation are automatically performed according to the ship's operating conditions, etc.

In addition, the operating company D and the actual ship E can communicate with the performance estimation system via the information and communication network 40. This allows the operating company D and the actual ship E to receive the actual sea area chart derived by the performance estimation system and transmit the operation data and observation data acquired in the actual sea area to the performance estimation system. In addition, the actual ship E during operation can automatically adjust the trim according to the received actual sea area chart.
Also, the actual sea area charting step S12, the correction step S13, and the replacement step S14 can be executed using a computer on board the actual ship E, and the trim can be corrected according to the actual sea area chart that has been derived by the computer.
Furthermore, the combination of the tank testing room A and its components, the CFD calculation room B and its components, the components of the center C, the computer 31 and its components, the operating company D, the actual ship E, etc. can be arbitrarily combined and arranged within the scope that does not deviate from their original purpose, and can be linked via the information and communications network 40.

The present invention can be used to estimate ship performance with high accuracy and optimize speed allocation, trim, and route operation.

S1: Hull condition acquisition step S2: Operation condition acquisition step S3: Tank test step S4: CFD calculation step S5: Resistance coefficient and self-propulsion element correction step S6: Hull resistance deriving step S7: Driving force deriving step S8: Horsepower deriving step S10: Fuel consumption deriving step S11: Charting step S12: Actual sea area charting step S13: Correction step S14: Replacement step S15: Automatic trim adjustment step S16: Correction value acquisition step S17: Condition acquisition step S18: Output step 21: Hull condition acquisition means 22: Operation condition acquisition means 23: Tank test means 24: CFD calculation means 25: Resistance coefficient and self-propulsion element correction means 26: Automatic production means 31: Computer 32: Input means 33: Output means 40: Information and communication network

Claims (25)

A performance estimation method for estimating the performance of a ship by a computer using a tank test and CFD (computational fluid dynamics) calculations, comprising the steps of:
a hull condition acquisition step in which the computer acquires hull conditions of the ship;
a navigation condition acquisition step in which the computer acquires navigation conditions of the ship;
a tank test step of performing the tank test using a model ship of the ship based on the hull conditions and the operating conditions, and the computer uses the results of the tank test to determine a resistance coefficient and a self-propulsion parameter of the ship;
a CFD calculation step in which the computer performs the CFD calculation based on the hull conditions and the operating conditions to obtain the resistance coefficient and the self-propulsion element of the ship;
A ship performance estimation method comprising a resistance coefficient and self-propulsion element correction step in which the computer calculates a difference between the resistance coefficient and the self-propulsion element obtained by the tank test and the CFD calculation, corrects the difference based on a set number of variables of the operating conditions in the tank test, and obtains corrected values for the resistance coefficient and the self-propulsion element. The method for estimating ship performance described in claim 1, characterized in that the operating conditions are at least one of the ship's speed, trim, draft, weather, and sea conditions. The method for estimating ship performance according to claim 1 or 2, characterized in that the resistance coefficients are the wave-making resistance coefficient, the shape influence coefficient, and the wave resistance increase coefficient, and the self-propulsion elements are the thrust reduction coefficient, the effective wake coefficient, and the propeller efficiency ratio. 4. A ship performance estimation method according to claim 1, wherein when the set number of the variables is one, the computer performs linear interpolation based on equation (1) to determine the correction value.
C: correction value _C1 : correction amount at test point 1 _C2 : correction amount at test point 2 _a1 : displacement amount from test point 1 4. A ship performance estimating method according to any one of claims 1 to 3, characterized in that, when the set number of variables is two, the computer performs linear interpolation based on equation (2) to determine the correction value.
C: correction value _C1 : correction amount at test point 1 _C2 : correction amount at test point 2 _C3 : correction amount at test point 3 _C4 : correction amount at test point 4 _a1 =(1-δξ-δη+δξδη)
a ₂ = δξ(1-δη)
_a3 = δξδη
a ₄ = δη(1-δξ)
δξ: The first variable of the variables is the displacement amount around the vector axis going from test point 1 to test point 2. δη: The second variable of the variables is the displacement amount around the vector axis going from test point 1 to test point 4. 4. A ship performance estimating method according to any one of claims 1 to 3, characterized in that, when the set number of variables is three, the computer performs linear interpolation based on equation (3) to determine the correction value.
C: Correction value _C1 : Correction amount at test point 1 _C2 : Correction amount at test point 2 _C3 : Correction amount at test point 3 _C4 : Correction amount at test point 4 _C5 : Correction amount at test point ₅ C6: Correction amount at test point 6 _C7 : Correction amount at test point 7 _C8 : Correction amount at test point 8 δξ: Displacement amount around the axis of the vector going from test point 1 to test point 2 for the first variable δη: Displacement amount around the axis of the vector going from test point 1 to test point 4 for the second variable δζ: Displacement amount around the axis of the vector going from test point 1 to test point 5 for the third variable A ship performance estimation method for estimating ship performance by a computer using the ship performance estimation method described in any one of claims 1 to 6, characterized in that the ship performance estimation method has a hull resistance derivation step in which the computer derives a relationship between the ship's speed and hull resistance based on the resistance coefficient and the correction value of the corrected resistance coefficient obtained in the self-propulsion element correction step. 8. A method for estimating ship performance as described in claim 7, further comprising a driving force derivation step in which the computer derives a relationship between the speed and driving force of the ship based on the correction value of the self-propulsion element. The ship performance estimation method as described in claim 8 , further comprising a horsepower derivation step in which the computer derives a relationship between the speed and horsepower of the ship based on the relationship between the speed and the hull resistance derived in the hull resistance derivation step and the relationship between the speed and the driving force derived in the driving force derivation step. The method for estimating ship performance described in claim 9, characterized in that the relationship between the speed and the horsepower takes into account the trim and draft of the ship. 11. The method for estimating performance of a vessel according to claim 10, further comprising a fuel consumption deriving step in which the computer determines a fuel consumption of the vessel for each of the speed and the trim of the vessel based on the horsepower. 12. The method of claim 11, further comprising a charting step in which the computer charts the relationship between the speed, the trim, and the fuel consumption of the vessel. The method for estimating ship performance as described in claim 12, further comprising an actual sea area charting step in which the computer obtains an actual sea area chart by taking into account weather and sea conditions and adding changes in the speed, trim, and fuel consumption of the ship in the actual sea area to the chart obtained in the charting step. The method for estimating ship performance as described in claim 13, further comprising a correction step in which the computer corrects the actual sea area chart taking into account operation data of the ship in the actual sea area. The ship performance estimation method as described in claim 13 or claim 14, further comprising a replacement step in which the computer replaces the actual sea area chart taking into account observation data of the weather and sea conditions encountered by the ship in the actual sea area. 16. A ship performance estimation method as claimed in any one of claims 13 to 15, further comprising an automatic trim adjustment step in which the computer takes into account loading information of the ship and automatically adjusts the trim of the ship in accordance with the actual sea area chart. A performance estimation program for estimating ship performance using the ship performance estimation method according to any one of claims 11 to 16, comprising:
On the computer,
a correction value acquisition step of acquiring the corrected resistance coefficient and the correction value of the self-propulsion element;
A condition acquisition step of acquiring at least the speed and the trim inputted;
A ship performance estimation program characterized by executing the hull resistance deriving step, the driving force deriving step, the horsepower deriving step, the fuel consumption deriving step, and an output step of outputting at least the derived results of the fuel consumption. The ship performance estimation program according to claim 17, which cites any one of claims 12 to 16, further causes the computer to execute the charting step. The ship performance estimation program according to claim 18, which cites any one of claims 13 to 16, further causes the computer to execute the actual sea area charting step. A performance estimation system that estimates the performance of a ship by using a water tank test and a CFD (computational fluid dynamics) calculation,
A hull condition acquisition means for acquiring hull conditions of the ship;
An operation condition acquisition means for acquiring operation conditions of the ship;
a tank test means for performing the tank test using a model ship of the ship based on the hull conditions and the operating conditions, and determining a resistance coefficient and a self-propulsion factor of the ship;
a CFD calculation means for performing the CFD calculation based on the hull conditions and the operating conditions, and determining the resistance coefficient and the self-propulsion element of the ship;
a resistance coefficient and self-propulsion element correction means for calculating a difference between the resistance coefficient and the self-propulsion element obtained by the tank test and the CFD calculation, correcting the difference based on the number of variables set for the operating conditions in the tank test, and obtaining corrected values for the resistance coefficient and the self-propulsion element. The ship performance estimation system described in claim 20, characterized in that the tank test means is an automated tank test means that automatically performs tests using the model ship and determines the resistance coefficient and the self-propulsion element. The ship performance estimation system according to claim 20 or 21, characterized in that it is provided with an automatic production means for the model ship, and the model ship is produced by the automatic production means based on the acquired hull conditions. A performance estimation system for estimating performance of a ship, comprising:
20. A ship performance estimation system comprising a computer, an input means for the computer, and an output means for the computer, the system being characterized in that the computer is caused to execute a ship performance estimation program according to any one of claims 17 to 19. The ship performance estimation system according to claim 23, characterized in that the ship is automatically operated based on the output from the output means. A ship performance estimation system characterized by connecting the ship performance estimation system according to any one of claims 20 to 22 and/or the ship performance estimation system according to claim 23 via an information and communication network and estimating the performance of the ship.