Method for forecasting paddle rudder interference hydrodynamic coefficient in wave based on ship model test

Abstract

The invention discloses a wave paddle rudder interference hydrodynamic coefficient forecasting method based on a ship model test, and relates to the technical field of ships. The method comprises the following steps: representing the coupling influence of a paddle and a rudder according to a ship body hydrodynamic force and an interference coefficient of the rudder to the ship body hydrodynamic force, and then fitting test data of direct navigation ship model tests under different rudder angles and ship model tests under different control parameters by utilizing a ship model test mode to obtain the interference coefficient; and the interference coefficient obtained by fitting can reflect the mutual interference and coupling effect between the paddle and the rudder in a numerical forecasting model of the rudder hydrodynamic force in the wave, so that the rudder hydrodynamic force in the wave influenced by the coupling of the paddle and the rudder can be forecasted. The method provides important support for researching a multi-free coupling motion interference mechanism and manipulation motion prediction in ship waves, and has the advantages of high precision, high reliability and the like.

Description

Technical Field

[0001] The present application relates to the field of ship technology, and in particular to a method for predicting hydrodynamic coefficients of propeller-rudder interference in waves based on ship model tests. Background Art

[0002] At present, the evaluation of ship maneuverability is mostly based on a calm water environment. However, when a ship maneuvers in an actual marine environment, it is affected by waves and will produce obvious sway coupling motion, which affects the ship's maneuverability safety. Therefore, predicting and evaluating the maneuverability of a ship in waves is of great significance for ship navigation safety, effective control, and improvement of ship combat capabilities, and has always been a research hotspot.

[0003] When a ship is maneuvering in waves, the swaying motion caused by the waves will affect the pressure changes around the hull and the hydrodynamic forces acting on the hull, propeller and rudder. Therefore, establishing a method to predict the hydrodynamic forces of ship maneuverability in waves and the interference hydrodynamic forces between the hull, propeller and rudder is an important basis for accurately predicting maneuvering motion in waves. The mutual interference between the hull, propeller and rudder during the ship maneuvering in waves is mainly manifested in the following aspects: (1) The interference of the hull on the rudder: The lateral velocity and bow angular velocity caused by the hull maneuvering motion change the speed and direction of the incoming flow in front of the rudder. (2) The interference of the propeller on the rudder: The swirl of the propeller affects the wake field at the rudder, changing the speed and direction of the incoming flow at the rudder. (3) The interference of the rudder on the hull: Steering causes the pressure distribution at the stern of the hull to change, generating the hull hydrodynamic force. (4) The influence of the ship movement in waves on the rudder force: When a ship is maneuvering in waves, it will produce swaying motion, causing the hydrodynamic forces acting on the propeller and rudder to change. Therefore, to accurately predict maneuvering motions in waves, it is necessary to consider the mutual interference between the hull, propeller and rudder in the waves.

[0004] At present, the main method for studying the maneuvering hydrodynamics in waves and the interference between the hull, propeller and rudder is based on the CFD method (Computational Fluid Dynamics, CFD). The CFD method uses overlapping grid technology to realize the multi-degree-of-freedom motion of the hull, and the sliding grid technology to realize the rotation of the propeller and the rotation of the rudder. Combined with numerical wave generation and wave elimination technology, a numerical model of the ship's maneuvering motion in waves is constructed to study the hull hydrodynamics, propeller thrust torque and rudder hydrodynamics under different propeller loads and different rudder angles in waves, thereby establishing a method for predicting the hydrodynamics of propeller-rudder interference in waves. However, the CFD method needs to simulate multi-degree-of-freedom coupled motion and relative motion, which makes prediction difficult. Summary of the invention

[0005] In view of the above problems and technical requirements, this application proposes a method for predicting the hydrodynamic coefficient of propeller-rudder interference in waves based on ship model tests. The technical solution of this application is as follows:

[0006] A method for predicting hydrodynamic coefficients of propeller and rudder interference in waves based on ship model tests, the method comprising:

[0007] Make a ship model corresponding to the target ship and assemble a force sensor on the ship model;

[0008] The ship model is subjected to direct-sailing ship model tests at different rudder angles in a wave environment, and the hull hydrodynamic force and rudder normal force of the ship model in each direct-sailing ship model test are collected through force sensors;

[0009] The ship model is tested with different maneuvering parameters in a wave environment, and the rudder normal force on the ship model during each ship model test is collected through a force sensor. The maneuvering parameters include propeller speed and rudder angle.

[0010] According to the hull hydrodynamic force and rudder normal force applied to the ship model during each direct-navigation ship model test, the interference coefficient of the rudder on the hull hydrodynamic force is obtained by fitting; according to the rudder normal force applied to the ship model during each ship model test, the interference coefficient of the hull and propeller wake on the flow velocity in front of the rudder is obtained by fitting;

[0011] Combined with the interference coefficient of the rudder on the hull hydrodynamics and the interference coefficient of the hull and propeller wake on the oncoming flow velocity in front of the rudder obtained from the test, a numerical prediction model of the rudder hydrodynamics in waves affected by the propeller-rudder coupling is constructed and the rudder hydrodynamics in waves is predicted. The numerical prediction model of the rudder hydrodynamics in waves affected by the propeller-rudder coupling is related to the interference coefficient of the rudder on the hull hydrodynamics and the interference coefficient of the hull and propeller wake on the oncoming flow velocity in front of the rudder.

[0012] The further technical solution is to construct a numerical prediction model of rudder hydrodynamics in waves under the influence of propeller-rudder coupling:

[0013] Among them, X R is the longitudinal component of the rudder hydrodynamic force in the waves, Y R is the lateral component of the rudder hydrodynamic force in waves, N R is the bow component of the rudder hydrodynamic force in waves, x R is the longitudinal distance between the rudder of the target ship and the center of gravity, δ is the rudder angle of the target ship; the rudder normal force on the target ship ρ represents the density of the waters where the target ship is located, A R represents the rudder area of ​​the target ship, f α represents the rudder force coefficient of the target ship, α R represents the effective rudder angle of the target ship's hull and propeller wake and U R represents the target ship's rudder combined speed and vR is the lateral velocity of the oncoming flow in front of the target ship’s rudder; u R represents the axial velocity of the target ship's rudder incoming flow and Propeller inlet flow speed u P =u(1-ω p ), u represents the longitudinal speed of the target ship, ω p represents the wake fraction of the target ship, k T represents the propeller thrust coefficient of the target ship, J represents the propeller advance coefficient of the target ship, the interference coefficients of the hull and propeller wake on the rudder flow velocity include k and ε, and the interference coefficient of the rudder on the hull hydrodynamics includes t R 、a H and x H .

[0014] A further technical solution is that the hydrodynamic force of the hull subjected to the ship model in each straight-line ship model test includes the longitudinal force X, the lateral force Y and the bow moment N of the hull, and the interference coefficient t of the rudder on the hydrodynamic force of the hull is obtained by fitting. R 、a H and x H include:

[0015] According to the size of the ship model, the longitudinal force X, lateral force Y, bow moment N and rudder normal force F of the ship model in each straight-line ship model test are calculated. n The dimensionless processing is performed respectively to obtain the dimensionless hull longitudinal force X', the dimensionless hull lateral force Y', the dimensionless hull bow moment N' and the dimensionless rudder normal force F n ';

[0016] According to the dimensionless rudder normal force F that the ship model is subjected to during each direct-flight ship model test n ' and the rudder angle d used in the straight-line ship model test m , calculate the F of each direct-flight ship model test n 'sind m and F n 'cosd m ;

[0017] The dimensionless longitudinal force X' of the hull on the ship model during each direct-navigation ship model test corresponds to the F n 'sind m Perform linear regression and use the slope of the linear regression as the interference coefficient t obtained by fitting R ;

[0018] The dimensionless lateral force Y' on the ship model during each direct-navigation ship model test corresponds to the F n 'cosd mPerform linear regression and use the slope of the linear regression as the interference coefficient a obtained by fitting H ;

[0019] The dimensionless bow moment N' of the ship model during each direct-navigation ship model test corresponds to the F n 'cosd m Perform linear regression and compare the slope of the linear regression with the interference coefficient a obtained by fitting. H The ratio of is taken as the interference coefficient x obtained by fitting H .

[0020] A further technical solution is to calculate the longitudinal force X, lateral force Y, bow moment N and rudder normal force F of the ship model in each straight-line ship model test according to the following formula according to the size of the ship model: n Perform dimensionless processing respectively:

[0021]

[0022] Among them, r m is the density of the fluid in the test pool where the ship model is located, V m is the speed of the ship model during the straight-line ship model test, L wl is the waterline length of the ship model, and d is the draft of the ship model.

[0023] A further technical solution is to fit the interference coefficients k and ε of the hull and propeller wake on the rudder flow velocity, including:

[0024] The axial velocity of the incoming flow in front of the rudder of the ship model is obtained by fitting the rudder normal force on the ship model in each ship model test and the rudder angle used.

[0025] Determine the propeller inflow velocity of the ship model in each ship model test and the speed coefficient J m ;

[0026] The ship model is tested in each ship model test Corresponding to the corresponding ship model test Linear regression fitting is performed to obtain the interference coefficients of the flow velocity in front of the rudder, including k and ε, where: Represents the propeller thrust coefficient of the ship model.

[0027] A further technical solution is to obtain the interference coefficient of the rudder oncoming flow velocity by fitting, including k and ε:

[0028] Determine the ship model during each ship model test Corresponding to the corresponding ship model test The intercept of the linear regression is ε 2 , the slope is ε2 ·k, the interference coefficient of the flow velocity before the rudder is calculated, including k and ε.

[0029] A further technical solution is to obtain the axial velocity of the rudder flow of the ship model by fitting include:

[0030] Calculate the derivative ξ of the normal force rudder angle curve between the rudder normal force and the rudder angle at the rudder angle of 0 in each ship model test, and obtain the axial velocity of the rudder flow in front of the ship model Among them, r m is the density of the fluid in the test pool where the ship model is located, A d is the rudder area of ​​the ship model, is the rudder force coefficient of the ship model.

[0031] A further technical solution is to determine the propeller inflow velocity of the ship model in each ship model test. and the speed coefficient J m include:

[0032] The propeller thrust T of the ship model during each ship model test is measured by the force sensor. m , and according to Get the propeller thrust coefficient of the ship model According to the propeller thrust coefficient Determine the advance coefficient J in the current ship model test by combining the propeller open water curve m , and according to Determine the propeller inflow velocity of the ship model in the current ship model test

[0033] or,

[0034] According to the longitudinal speed u of the ship model in each ship model test m Combined with the wake fraction ω of the ship model in open water P0 Get the propeller inflow velocity of the ship model in the current ship model test And according to Determine the speed coefficient J in the current ship model test m ;

[0035] Among them, n is the propeller speed of the ship model, and D is the propeller diameter of the ship model.

[0036] A further technical solution is that the method for predicting the hydrodynamic coefficient of propeller and rudder interference in waves also includes:

[0037] The ship model is tested for straight sailing at different rudder angles and different maneuvering parameters in a wave environment with each wave parameter, and the interference coefficient group corresponding to the current wave parameter is fitted. The interference coefficient group corresponding to each wave parameter includes the interference coefficient of the rudder on the hydrodynamic force of the hull under the current wave parameter, and the interference coefficient of the hull and propeller wake on the flow velocity in front of the rudder; the ship model is tested for different wave environments with different wave parameters, and the interference coefficient group corresponding to each wave parameter is fitted respectively;

[0038] The interference coefficient group corresponding to the target wave parameters is used to construct a numerical prediction model of the rudder hydrodynamics of the target ship in waves under the target wave parameters, and the rudder hydrodynamics of the target ship in waves under the target wave parameters is predicted.

[0039] A further technical solution is to make a ship model corresponding to the target ship and assemble a force sensor on the ship model, including:

[0040] A ship model corresponding to the target ship is produced under the similarity criteria of geometric similarity, motion similarity and power similarity, and the ship model is equipped with a propulsion system, a steering system and a data acquisition system;

[0041] The force sensors installed on the ship model include a hull hydrodynamic force balance, a propeller thrust and torque self-propulsion instrument and a rudder force balance.

[0042] The beneficial technical effects of this application are:

[0043] The present application discloses a method for predicting the hydrodynamic coefficient of propeller-rudder interference in waves based on a ship model test. The method uses the interference coefficients k and ε of the hull and propeller wake on the incoming flow velocity in front of the rudder in the hydrodynamic expression of the rudder in waves under the influence of propeller-rudder coupling on the ship, and the interference coefficient t of the rudder on the hull hydrodynamics. R 、a H and x H To characterize the coupling effect of propeller and rudder, the interference coefficient t of the rudder on the hydrodynamic force of the hull is obtained by fitting the test data of the straight-line ship model test under different rudder angles. R 、a H and x H , by fitting the interference coefficients k and ε of the propeller wake on the rudder front flow velocity under different maneuvering parameters, a numerical prediction model of the rudder hydrodynamics in waves can be constructed, so as to predict the rudder hydrodynamics in waves affected by the ship-propeller-rudder coupling, and then provide a technical basis for the prediction of the maneuvering motion of the target ship. This method is used to solve the difficult problems of testing and analyzing the hydrodynamics of the hull, propeller and rudder in waves, analyzing and expressing the hydrodynamics of the ship-propeller-rudder interference in waves, and provides important support for studying the interference mechanism of multi-freedom coupled motions of ships in waves and the prediction of maneuvering motions, and has the advantages of high accuracy and high reliability.

[0044] This method can fit the interference coefficient groups corresponding to different wave parameters through the ship model test results under different wave environments, so that a more matching interference coefficient group can be used in different wave environments to construct a numerical model for predicting the hydrodynamics of the rudder in waves under the corresponding wave environment, thereby further improving the accuracy of the prediction of the hydrodynamics of the rudder in waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of the geodetic coordinate system and the ship coordinate system used in the prediction of the hydrodynamic coefficient of propeller and rudder interference in waves of the present application.

[0046] Figure 2 This is a flow chart of a method for predicting the hydrodynamic coefficient of propeller and rudder interference in waves according to an embodiment of the present application.

[0047] Figure 3 is the dimensionless bow moment N' of the ship model in each direct-flight ship model test in an example of the present application, which corresponds to the F of the corresponding direct-flight ship model test. n 'cosd m Plot the results of linear regression.

[0048] Figure 4 This is an example of the application of the ship model in each ship model test Corresponding to the corresponding ship model test Plot the results of linear regression. DETAILED DESCRIPTION

[0049] The specific implementation of the present application is further described below in conjunction with the accompanying drawings.

[0050] The present application discloses a method for predicting the hydrodynamic coefficients of propeller-rudder interference in waves based on a ship model test. The method focuses on providing a numerical prediction model of the hydrodynamic force of the rudder in waves affected by the coupling of propeller and rudder. Before providing the numerical prediction model of the hydrodynamic force of the rudder in waves, the geodetic coordinate system O-x0y0z0 and the ship coordinate system o-xyz used are first defined as follows: Figure 1As shown, both coordinate systems satisfy the right-hand rule. In the ship-borne coordinate system o-xyz, the coordinate origin o is located at the center of gravity of the target ship, the ox axis points to the bow along the centerline of the ship, and oy points to the starboard. The angle ψ between the Ox0 axis and the ox axis is defined as the heading angle of the target ship. It is stipulated that the positive direction of ψ is the direction around the Oz0 axis to the ox axis according to the right-hand rule with the Ox0 axis as the starting position. The angle β between the speed U direction of the target ship and the ox axis is defined as the drift angle. It is stipulated that the positive direction of the drift angle β is the direction around the Oz0 axis to the ox axis according to the right-hand rule with the velocity vector direction as the starting position. The angle between the wave propagation direction and the Ox0 axis is defined as the wave direction angle χ. It is stipulated that the positive direction of the wave direction angle χ is the direction around the Oz0 axis to the wave propagation direction according to the right-hand rule with the Ox0 axis as the starting position. The wave propagates along the Ox0 axis direction χ=0°. The rudder angle δ of the target ship is positive when it rotates to the starboard side of the hull.

[0051] Then, based on the MMG model, the hull hydrodynamic force, propeller thrust and rudder hydrodynamic force in waves are expressed separately, so that the model form of the numerical model of the maneuvering motion of the target ship in waves is given as follows:

[0052]

[0053] Where m is the mass of the target ship, m x is the longitudinal additional mass of the target ship, m y is the transverse additional mass of the target ship, I Z is the moment of inertia around the oz axis of the ship coordinate system. u is the longitudinal velocity of the target ship, v is the lateral velocity of the target ship, and r is the bow angular velocity of the target ship.

[0054] In the numerical model of wave maneuvering motion constructed in the present application as shown in formula (1), the external forces acting on the target ship include the hull hydrodynamic force, propeller thrust, and the wave rudder hydrodynamic force affected by the ship-propeller-rudder coupling. H , Y H 、N H These are the longitudinal component, transverse component and bow turning component of the hydrodynamic force acting on the target ship. P , Y P 、N P They are the longitudinal component, transverse component and bow component of the propeller thrust on the target ship. R , Y R 、N R They are the longitudinal component, transverse component and bow turning component of the rudder hydrodynamic force in the waves acting on the target ship.

[0055] The mutual interference and coupling effects between ship, propeller and rudder are reflected in the rudder hydrodynamics in waves. Therefore, in the above numerical model of maneuvering motion in waves, the hull hydrodynamics of the target ship is the hull hydrodynamics without propellers and rudders, that is, the hull hydrodynamics is the light body hydrodynamics without considering the influence of propellers and rudders. Therefore, the hull hydrodynamics and propeller thrust of the target ship can be directly determined according to conventional methods.

[0056] The wave rudder hydrodynamics in the numerical model of wave maneuvering motion needs to consider the mutual interference and coupling effect between ship, propeller and rudder. The numerical prediction model of the wave rudder hydrodynamics under the influence of ship-propeller-rudder coupling on the target ship can be expressed as:

[0057]

[0058] Among them, x R is the longitudinal distance of the target ship’s rudder from the center of gravity. δ is the target ship’s rudder angle. F N represents the rudder normal force on the target ship and ρ represents the density of the waters where the target ship is located, A R represents the rudder area of ​​the target ship, f α Indicates the rudder force coefficient of the target ship.

[0059] U R represents the target ship's rudder combined speed and v R is the lateral velocity of the flow in front of the target ship, u R Indicates the axial velocity of the flow in front of the target ship. R represents the effective rudder angle of the target ship's hull and propeller wake and

[0060] Axial velocity of the target ship's rudder flow Propeller inlet flow speed u P =u(1-ω p ), u represents the longitudinal speed of the target ship, ω p represents the wake fraction of the target ship, k T represents the propeller thrust coefficient of the target ship, and J represents the propeller advance coefficient of the target ship.

[0061] Based on the above constructed expressions, it can be seen that the rudder hydrodynamic force in waves under the influence of propeller-rudder coupling on the target ship is not only related to the rudder angle δ during the maneuvering process, but also to the interference coefficients k, ε, t R 、a H and x H Among them, the interference coefficients k and ε are used to characterize the influence of the hull and propeller wake on the rudder flow velocity, and the interference coefficient t R 、aH and x H It is used to characterize the influence of the rudder on the hydrodynamics of the hull. Therefore, these two types of interference coefficients can be used to take the interference hydrodynamics between the hull, propeller and rudder into account in the rudder hydrodynamics in waves, thereby laying a technical foundation for the accurate prediction of ship maneuvering motions in waves.

[0062] Through the above analysis, it can be seen that this application provides the model form of the numerical model of maneuvering motion in waves and the expression form of the numerical prediction model of the rudder hydrodynamics in waves under the influence of the ship-propeller-rudder coupling. The focus is on determining the interference coefficients k and ε of the hull and propeller wake on the rudder front flow velocity in the numerical prediction model of the rudder hydrodynamics in waves, as well as the interference coefficient t of the rudder on the hull hydrodynamics. R 、a H and x H This application uses a ship model test to determine the two sets of interference coefficients, including the following steps, please refer to Figure 2 The flowchart shown:

[0063] 1. Make a ship model corresponding to the target ship and assemble a force sensor on the ship model

[0064] Firstly, a ship model corresponding to the target ship is made under the similarity criteria of geometric similarity, motion similarity and dynamic similarity. The made ship model is equipped with necessary propulsion system, steering system and data acquisition system.

[0065] The similarity criteria to be met when making a ship model include: (1) The shape of the main appendages of the ship model meets the geometric similarity with the actual ship of the target ship. (2) The longitudinal position and height of the center of gravity of the ship model are geometrically similar to the actual ship of the target ship. (3) The speed of the ship model and the actual ship of the target ship meet the Froude similarity. (4) The attitude angle of the ship model is equal to that of the actual ship of the target ship.

[0066] The propulsion system on the ship model mainly includes motors, shafts and propellers. The steering system on the ship model mainly includes steering gear and rudder. The data acquisition system on the ship model mainly includes equipment for collecting parameters such as the ship model's heel angle, heading angle and rudder angle. The hydrodynamic test device on the ship model can release the three degrees of freedom of heave, pitch and roll; and constrain the three degrees of freedom of longitudinal, transverse and bow roll.

[0067] Then, a hydrodynamic test device containing force sensors is installed on the ship model. The hydrodynamic test device can release the three degrees of freedom of heave, pitch and roll, and constrain the three degrees of freedom of longitudinal, transverse and bow. The hydrodynamic test device is equipped with force sensors, including a hull hydrodynamic force balance, a propeller thrust and torque auto-propeller, and a rudder force balance. The hull hydrodynamic force balance is used to collect the hull hydrodynamics of the three degrees of freedom of longitudinal, transverse and bow, the propeller thrust and torque auto-propeller is used to collect the propeller thrust, and the rudder force balance is used to collect the rudder normal force.

[0068] Before the ship model test, the force sensors will be calibrated to obtain the calibration coefficient between the electrical signal and the hydrodynamic force. The center of gravity and inertia of the ship model will also be adjusted to meet the mass distribution requirements.

[0069] 2. Build a test environment.

[0070] This application conducts ship model tests in a test pool to test the wave-making and wave-breaking capabilities of the test pool. According to the test requirements, a wave environment with corresponding wave parameters can be generated. Each set of wave parameters includes wave height and period. This application mainly selects regular waves to construct a wave environment. The wavelength is selected as 0.5-2.0 times the length of the ship, and the wave steepness is generally 1 / 50. Before the test, the corresponding wave environment is generated according to the wave parameters, and wave debugging is performed in the test area of ​​the test pool so that the wave period and wave height meet the test requirements, thereby constructing the required stable wave environment in the test pool.

[0071] 3. Place the ship model in a water tank for testing

[0072] This includes conducting straight-ahead ship model tests with different rudder angles and ship model tests with different maneuvering parameters in a constructed wave environment, and collecting test data in the ship model test under each working condition. The maneuvering parameters include propeller speed and rudder angle.

[0073] Whether conducting a direct-flight ship model test or a ship model test, the specific test method under each working condition includes: setting the target speed on the trailer, setting the rudder angle and propeller speed of the ship model during the current test, then generating a stable wave environment, and starting the propellers of the trailer and the ship model. After the trailer speed stabilizes, start collecting and recording the test data. Finally, before the trailer stops, stop collecting the test data, turn off the ship model propeller and wave maker system, and the ship model test of one working condition is completed. A working condition can be tested repeatedly according to actual conditions to ensure that each working condition has multiple valid voyages of ship model test data, thereby reducing accidental errors in a single test process. After the ship model test of each working condition is completed, adjust the rudder angle and propeller speed of the ship model to continue the ship model test under other working conditions.

[0074] When conducting direct-flight ship model tests at different rudder angles, the test data collected in each direct-flight ship model test include the hull hydrodynamic force and rudder normal force F acting on the ship model collected by the force sensor. n , where the hull hydrodynamic force on the ship model includes the hull longitudinal force X, hull lateral force Y and hull bow moment N acting on the three degrees of freedom of the ship model in the restrained mode state, where the action center of the hull bow moment N is at the center of gravity of the ship model. In one example, when conducting a direct-sail ship model test with different rudder angles, the rudder angle is selected every 5° in the range of 25° to 25° to the left to conduct the direct-sail ship model test.

[0075] When conducting ship model tests with different maneuvering parameters, the test data collected in each ship model test include the rudder normal force F on the ship model collected by the force sensor. n In some other embodiments, the propeller thrust T of the ship model is also collected by the force sensor. m In one example, when conducting a ship model test with different maneuvering parameters on a ship model, rudder angles were selected at intervals of 5° in the range of 25° to the left and 25° to the right, and three different propeller speeds were selected. The selected rudder angles and propeller speeds were fully permuted and combined to obtain multiple sets of maneuvering parameters for the ship model test.

[0076] Regardless of the type of ship model test, in the actual test process, the hull hydrodynamic force and rudder normal force F of the ship model directly collected by the force sensor during the test process are n and propeller thrust T m They are all time history curves. After collecting the original time history curves, the time history curves of each type of test data are averaged as the value of the test data. When this application subsequently processes the test data of the ship model test under each working condition, the value of the test data after calculating the average is used.

[0077] 4. The interference coefficient is obtained by fitting the test data during the ship model test.

[0078] (1) The interference coefficient t of the rudder on the hull hydrodynamics is obtained by fitting R 、a H and x H .

[0079] Including fitting the interference coefficient t of the rudder on the hull hydrodynamic force according to the hull hydrodynamic force and rudder normal force of the ship model during each direct-flight ship model test R 、a H and x H , specifically:

[0080] Firstly, the longitudinal force X, lateral force Y, bow moment N and rudder normal force F of the ship model in each straight-line ship model test are calculated according to the size of the ship model. n The dimensionless processing is performed respectively to obtain the dimensionless hull longitudinal force X', the dimensionless hull lateral force Y', the dimensionless hull bow moment N' and the dimensionless rudder normal force F n '. The dimensionless processing formula is:

[0081]

[0082] Among them, r m is the density of the fluid in the test pool where the ship model is located, V mis the speed of the ship model during the straight-line ship model test, L wl is the waterline length of the ship model, and d is the draft of the ship model.

[0083] Based on the expression of rudder hydrodynamics in waves from equation (2), the increment of hull hydrodynamics caused by the interference of rudder can be described as follows: The increment of non-dimensionalized hull longitudinal force X' is t R F N ′sinδ m , the increment of the dimensionless hull lateral force Y' is -a H F N ′cosδ m , the increment of the dimensionless bow moment N' is -a H x′ H F N ′cosδ m , d m It is the rudder angle of the ship model.

[0084] Based on this, according to the dimensionless rudder normal force F that the ship model is subjected to during each direct-flight ship model test, n ' and the rudder angle d used in the straight-line ship model test m , calculate the F of each direct-flight ship model test n 'sind m and F n 'cosd m .

[0085] Then the dimensionless longitudinal force X' of the hull subjected to the ship model in each direct-navigation ship model test is corresponding to the F n 'sind m Perform linear regression and use the slope of the linear regression as the interference coefficient t obtained by fitting R .

[0086] The dimensionless hull lateral force Y' on the ship model during each direct-navigation ship model test corresponds to the F n 'cosd m Perform linear regression and use the slope of the linear regression as the interference coefficient a obtained by fitting H .

[0087] The dimensionless bow moment N' of the ship model during each direct-navigation ship model test corresponds to the F n 'cosd m Perform linear regression and compare the slope of the linear regression with the interference coefficient a obtained by fitting. H The ratio of is taken as the interference coefficient x obtained by fitting H .

[0088] For example, in one example, the dimensionless bow moment N' of the ship model during each direct-flight ship model test corresponds to the F of the corresponding direct-flight ship model test. n 'cosd m The result of linear regression is as follows Figure 3 As shown, the slope of the linear regression is used to fit the interference coefficient a H The interference coefficient x can be calculated H .

[0089] (2) The interference coefficients k and ε of the hull and propeller wake on the rudder flow velocity are obtained by fitting.

[0090] According to the rudder normal force on the ship model during each ship model test, the interference coefficients k and ε of the hull and propeller wake on the flow velocity in front of the rudder are obtained by fitting.

[0091] The rudder normal force F on the target ship introduced above N The expression form is the same as that of , and the rudder normal force on the ship model can be expressed as Among them, ρ m is the density of the fluid in the test pool where the ship model is located, A d is the rudder area of ​​the ship model, is the rudder force coefficient of the ship model and can be obtained by to calculate, λ is the aspect ratio of the rudder of the ship model. is the effective rudder angle of the hull and propeller wake of the ship model and d m It is the rudder angle of the ship model. The rudder of the ship model is used to match the speed and is the axial velocity of the incoming flow in front of the rudder of the ship model, is the lateral velocity of the incoming flow in front of the rudder of the ship model.

[0092] The rudder normal force F on the ship model n Rudder angle d relative to the ship model m The derivation result is When considering the influence of the hull and propeller on the axial flow velocity in front of the rudder, directly take Therefore, the following expression can be obtained

[0093] Based on this analysis, the axial velocity of the rudder flow in front of the ship model can be obtained by fitting the rudder normal force and the rudder angle used in each ship model test. Including: calculating the derivative ξ of the normal force rudder angle curve between the rudder normal force and the rudder angle of the ship model in each ship model test at the rudder angle of 0, and obtaining the axial velocity of the rudder flow in front of the ship model

[0094] Then determine the propeller inflow velocity of the ship model in each ship model test and the speed coefficient J m There are two main ways: (a) When conducting a ship model test, the force sensor is also used to measure the propeller thrust T of the ship model during the current ship model test. m , and then the propeller thrust T m , obtain the propeller thrust coefficient of the ship model Then, the corresponding advance coefficient J is obtained by further combining the propeller open water curve (propeller thrust torque curve under different advance coefficients). m , then follow Determine the propeller inflow velocity of the ship model in the current ship model test Where n is the propeller speed of the ship model and D is the propeller diameter of the ship model. (b) According to the longitudinal speed u of the ship model in each ship model test m Combined with the wake fraction ω of the ship model in open water P0 Get the propeller inflow velocity of the ship model in the current ship model test In this case, it is also possible to further combine the propeller inflow speed in each ship model test And the propeller speed n used to determine the speed coefficient of each ship model test

[0095] Regardless of the method used, the propeller inflow velocity in each ship model test is determined and the speed coefficient J m After that, due to the axial velocity of the incoming flow from the rudder of the ship model and propeller inlet velocity There is the following relationship Therefore, the ship model is tested in each ship model test. Corresponding to the corresponding ship model test Linear regression fitting can be used to obtain the interference coefficients of the incoming flow velocity in front of the rudder, including k and ε, including determining the ship model at each ship model test. Corresponding to the corresponding ship model test The intercept of the linear regression is ε 2 , the slope is ε 2 ·k, and thus the interference coefficient of the flow velocity in front of the rudder is calculated, including k and ε. For example, in one example, the ship model is tested in each ship model test. Corresponding to the corresponding ship model test The result of linear regression is as follows Figure 4 shown.

[0096] The interference coefficients k, ε, and t can be obtained by fitting through the above method. R 、a H and x HBy substituting the fitted interference coefficient into the model form of formula (2), a numerical prediction model of the rudder hydrodynamics in waves that takes into account the mutual interference and coupling effects between the ship, propeller and rudder can be constructed. The constructed numerical prediction model can be used to predict the rudder hydrodynamics in waves, thereby providing a basis for predicting the maneuvering motion of the target ship in waves.

[0097] In addition, the mutual interference and coupling effects between the ship, propeller and rudder are actually different in different wave environments. Therefore, in another embodiment, the above-mentioned direct-flight ship model test with different rudder angles and the ship model test with different maneuvering parameters are carried out on the ship model in the wave environment with each wave parameter, and then the interference coefficient group corresponding to the current wave parameter is fitted. The interference coefficient group corresponding to each wave parameter includes the interference coefficient of the rudder on the hydrodynamic force of the hull under the current wave parameter, and the interference coefficient of the hull and propeller wake on the flow velocity in front of the rudder. Then, the wave parameters of the wave environment in the test pool are changed, and the ship model tests are carried out on the ship model in the wave environment with different wave parameters, so as to fit the interference coefficient groups corresponding to a variety of different wave parameters.

[0098] Then, the interference coefficient group corresponding to different wave parameters can be used to construct a numerical prediction model of the rudder hydrodynamics of the target ship in waves under different wave parameters. That is, when it is necessary to predict the rudder hydrodynamics of the target ship in waves under target wave parameters, it is only necessary to substitute the interference coefficient group corresponding to the target wave parameters into the model form of the numerical prediction model of the rudder hydrodynamics in waves of formula (2), and the numerical prediction model of the rudder hydrodynamics in waves matching the target wave parameters can be obtained, so that the rudder hydrodynamics of the target ship in waves under the target wave parameters can be accurately predicted.

[0099] The above is only a preferred embodiment of the present application, and the present application is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present application should be considered to be included in the protection scope of the present application.

Claims

1. A method for predicting hydrodynamic coefficients of propeller-rudder interference in waves based on ship model tests, characterized in that: The method for predicting hydrodynamic coefficients of propeller and rudder interference in waves includes: Making a ship model corresponding to the target ship and assembling a force sensor on the ship model; Conducting a direct-sail ship model test at different rudder angles in a wave environment on the ship model, and collecting the hull hydrodynamic force and rudder normal force exerted on the ship model during each direct-sail ship model test through a force sensor; Performing ship model tests with different maneuvering parameters on the ship model in a wave environment, and collecting the rudder normal force on the ship model during each ship model test through a force sensor, wherein the maneuvering parameters include propeller speed and rudder angle; The interference coefficient of the rudder on the hull hydrodynamic force is obtained by fitting the hull hydrodynamic force and the rudder normal force on the ship model during each direct-flight ship model test, and the interference coefficient of the hull and propeller wake on the rudder front flow velocity is obtained by fitting the rudder normal force on the ship model during each ship model test; Combined with the interference coefficient of the rudder on the hull hydrodynamics and the interference coefficient of the hull and propeller wake on the oncoming flow velocity in front of the rudder obtained from the test, a numerical prediction model of the rudder hydrodynamics in waves affected by the propeller-rudder coupling is constructed and the rudder hydrodynamics in waves is predicted. The numerical prediction model of the rudder hydrodynamics in waves affected by the propeller-rudder coupling is related to the rudder angle, the interference coefficient of the rudder on the hull hydrodynamics, and the interference coefficient of the hull and propeller wake on the oncoming flow velocity in front of the rudder.

2. The method for predicting hydrodynamic coefficients of propeller and rudder interference in waves according to claim 1 is characterized in that: The numerical prediction model of rudder hydrodynamics in waves under the influence of propeller-rudder coupling is constructed as follows: Among them, X R is the longitudinal component of the rudder hydrodynamic force in the waves, Y R is the lateral component of the rudder hydrodynamic force in waves, N R is the bow component of the rudder hydrodynamic force in waves, x R is the longitudinal distance between the rudder of the target ship and the center of gravity, δ is the rudder angle of the target ship; the rudder normal force on the target ship ρ represents the density of the waters where the target ship is located, A R represents the rudder area of ​​the target ship, f α represents the rudder force coefficient of the target ship, α R represents the effective rudder angle of the target ship's hull and propeller wake and U R represents the target ship's rudder combined speed and v R is the lateral velocity of the oncoming flow in front of the target ship’s rudder; u R represents the axial velocity of the target ship's rudder incoming flow and Propeller inlet flow speed u P =u(1-ω p ), u represents the longitudinal speed of the target ship, ω p represents the wake fraction of the target ship, k T represents the propeller thrust coefficient of the target ship, J represents the propeller advance coefficient of the target ship, the interference coefficients of the hull and propeller wake on the rudder flow velocity include k and ε, and the interference coefficient of the rudder on the hull hydrodynamics includes t R 、a H and x H .

3. The method for predicting hydrodynamic coefficients of propeller and rudder interference in waves according to claim 2 is characterized in that: The hydrodynamic forces on the ship model during each straight-line ship model test include the longitudinal force X, the lateral force Y and the bow moment N. The interference coefficient t of the rudder on the hydrodynamic force of the ship is obtained by fitting. R 、a H and x H include: According to the size of the ship model, the longitudinal force X, lateral force Y, bow moment N and rudder normal force F of the ship model in each straight-line ship model test are calculated. n The dimensionless processing is performed respectively to obtain the dimensionless hull longitudinal force X', the dimensionless hull lateral force Y', the dimensionless hull bow moment N' and the dimensionless rudder normal force F n '; According to the dimensionless rudder normal force F that the ship model is subjected to during each direct-flight ship model test n ' and the rudder angle d used in the straight-line ship model test m , calculate the F of each direct-flight ship model test n 'sind m and F n 'cosd m ; The dimensionless longitudinal force X' of the hull on the ship model during each direct-navigation ship model test corresponds to the F n 'sind m Perform linear regression and use the slope of the linear regression as the interference coefficient t obtained by fitting R ; The dimensionless hull lateral force Y' on the ship model during each direct-navigation ship model test corresponds to the F n 'cosd m Perform linear regression and use the slope of the linear regression as the interference coefficient a obtained by fitting H ; The dimensionless bow moment N' of the ship model during each direct-navigation ship model test corresponds to the F n 'cosd m Perform linear regression and compare the slope of the linear regression with the interference coefficient a obtained by fitting. H The ratio of is taken as the interference coefficient x obtained by fitting H .

4. The method for predicting hydrodynamic coefficients of propeller and rudder interference in waves according to claim 3 is characterized in that: According to the ship model size, the hull longitudinal force X, hull lateral force Y, hull bow moment N and rudder normal force F applied to the ship model in each straight-line ship model test are calculated according to the following formula: n Perform dimensionless processing respectively: Among them, r m is the density of the fluid in the test pool where the ship model is located, V m is the speed of the ship model during the straight-line ship model test, L wl is the waterline length of the ship model, and d is the draft of the ship model.

5. The method for predicting hydrodynamic coefficients of propeller and rudder interference in waves according to claim 2 is characterized in that: The interference coefficients k and ε of the hull and propeller wake on the rudder flow velocity obtained by fitting include: The axial velocity of the incoming flow in front of the rudder of the ship model is obtained by fitting the rudder normal force on the ship model in each ship model test and the rudder angle used. Determine the propeller inflow velocity of the ship model in each ship model test and the speed coefficient J m ; The ship model is tested in each ship model test Corresponding to the corresponding ship model test Linear regression fitting is performed to obtain the interference coefficients of the flow velocity in front of the rudder, including k and ε, where: Represents the propeller thrust coefficient of the ship model.

6. The method for predicting hydrodynamic coefficients of propeller and rudder interference in waves according to claim 5 is characterized in that: The interference coefficients of the flow velocity before the rudder obtained by fitting include k and ε: Determine the ship model during each ship model test Corresponding to the corresponding ship model test The intercept of the linear regression is ε 2 , the slope is ε 2 ·k, the interference coefficient of the flow velocity before the rudder is calculated, including k and ε.

7. The method for predicting hydrodynamic coefficients of propeller and rudder interference in waves according to claim 5, characterized in that: The axial velocity of the rudder flow of the ship model is obtained by fitting include: Calculate the derivative ξ of the normal force rudder angle curve between the rudder normal force and the rudder angle at the rudder angle of 0 in each ship model test, and obtain the axial velocity of the rudder flow in front of the ship model Among them, r m is the density of the fluid in the test pool where the ship model is located, A d is the rudder area of ​​the ship model, is the rudder force coefficient of the ship model.

8. The method for predicting hydrodynamic coefficients of propeller and rudder interference in waves according to claim 5, characterized in that: Determine the propeller inflow velocity of the ship model in each ship model test and the speed coefficient J m include: The propeller thrust T of the ship model during each ship model test is measured by the force sensor. m , and according to Get the propeller thrust coefficient of the ship model According to the propeller thrust coefficient Determine the advance coefficient J in the current ship model test by combining the propeller open water curve m , and according to Determine the propeller inflow velocity of the ship model in the current ship model test or, According to the longitudinal speed u of the ship model in each ship model test m Combined with the wake fraction ω of the ship model in open water P0 Get the propeller inflow velocity of the ship model in the current ship model test And according to Determine the speed coefficient J in the current ship model test m ; Among them, n is the propeller speed of the ship model, and D is the propeller diameter of the ship model.

9. The method for predicting hydrodynamic coefficients of propeller and rudder interference in waves according to claim 1, characterized in that: The method for predicting hydrodynamic coefficients of propeller and rudder interference in waves also includes: The ship model is subjected to direct sailing ship model tests at different rudder angles and ship model tests at different maneuvering parameters in a wave environment with each wave parameter, and an interference coefficient group corresponding to the current wave parameter is obtained by fitting, wherein the interference coefficient group corresponding to each wave parameter includes an interference coefficient of the rudder on the hydrodynamic force of the hull under the current wave parameter, and an interference coefficient of the hull and propeller wake on the flow velocity in front of the rudder; the ship model is subjected to ship model tests in wave environments with multiple different wave parameters, and the interference coefficient groups corresponding to each wave parameter are obtained by fitting respectively; A numerical prediction model of the rudder hydrodynamics of a target ship in waves under the target wave parameters is constructed by using the interference coefficient group corresponding to the target wave parameters, and the rudder hydrodynamics of the target ship in waves under the target wave parameters is predicted.

10. The method for predicting hydrodynamic coefficients of propeller and rudder interference in waves according to claim 1, characterized in that: The method of making a ship model corresponding to the target ship and assembling a force sensor on the ship model comprises: Producing a ship model corresponding to the target ship under similarity criteria of geometric similarity, motion similarity and power similarity, wherein the ship model is equipped with a propulsion system, a steering system and a data acquisition system; The force sensors installed on the ship model include a hull hydrodynamic force balance, a propeller thrust torque self-propulsion instrument and a rudder force balance.

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