This paper presents hybrid Reynolds-averaged Navier-Stokes （RANS） and large-eddy-simulation （LES） methods for the separated flows at high angles of attack around a 6：1 prolate spheroid. The RANS/LES hybrid meth- ...This paper presents hybrid Reynolds-averaged Navier-Stokes （RANS） and large-eddy-simulation （LES） methods for the separated flows at high angles of attack around a 6：1 prolate spheroid. The RANS/LES hybrid meth- ods studied in this work include the detached eddy simulation （DES） based on Spalart-Allmaras （S-A）, Menter＇s k-ω shear-stress-transport （SST） and k-o9 with weakly nonlinear eddy viscosity formulation （Wilcox-Durbin＋, WD＋） models and the zonalANS/LES methods based on the SST and WD＋ models. The switch from RANS near the wall to LES in the core flow region is smooth through the implementation of a flow-dependent blending function for the zonal hybrid method. All the hybrid methods are designed to have a RANS mode for the attached flows and have a LES behavior for the separated flows. The main objective of this paper is to apply the hybrid methods for the high Reynolds number separated flows around prolate spheroid at high-incidences. A fourth-order central scheme with fourth-order artificial viscosity is applied for spatial differencing. The fully implicit lower-upper symmetric-Gauss-Seidel with pseudo time sub-iteration is taken as the temporal differentiation. Comparisons with available measurements are carried out for pressure distribution, skin friction, and profiles of velocity, etc. Reasonable agreement with the experiments, accounting for the effect on grids and fundamental turbulence models, is obtained for the separation flows.展开更多
An investigation of the effect of simplifying bogie regions on the aerodynamic performance of a high-speed train was carried out by studying four train models,to explore possible ways to optimise the train underbody s...An investigation of the effect of simplifying bogie regions on the aerodynamic performance of a high-speed train was carried out by studying four train models,to explore possible ways to optimise the train underbody structure,improve the underbody aerodynamic performance,and reduce the aerodynamic drag.The shear stress transport(SST)k-ωturbulence model was used to study the airflow features of the high-speed train with different bogie regions at Re=2.25×10^(6).The calculated aerodynamic drag and surface pressure were compared with the experimental benchmark of wind tunnel tests.The results show that the SST k-ωmodel presents high accuracy in predicting the flow fields around the train,and the numerical results closely agree with the experimental data.Compared with the train with simplified bogies,the aerodynamic drag of the train with a smooth surface and the train with enclosed bogie cavities/inter-carriage gaps decreases by 38.2%and 30.3%,respectively,while it increases by 10.8%for the train with cavities but no bogies.Thus,enclosing bogie cavities shows a good capability of aerodynamic drag reduction for a new generation of highspeed trains.展开更多
In order to reduce the total resistance of a hull, an optimization framework for the bulbous bow optimization was presented. The total resistance in calm water was selected as the objective function, and the overset m...In order to reduce the total resistance of a hull, an optimization framework for the bulbous bow optimization was presented. The total resistance in calm water was selected as the objective function, and the overset mesh technique was used for mesh generation. RANS method was used to calculate the total resistance of the hull. In order to improve the efficiency and smoothness of the geometric reconstruction, the arbitrary shape deformation （ASD） technique was introduced to change the shape of the bulbous bow. To improve the global search ability of the particle swarm optimization （PSO） algorithm, an improved particle swarm optimization （IPSO） algorithm was proposed to set up the optimization model. After a series of optimization analyses, the optimal hull form was found. It can be concluded that the simulation based design framework built in this paper is a promising method for bulbous bow optimization.展开更多
Based on the incompressible RANS equation,the KVLCC1 ship’s resistance field’s numerical simulation is carried out.In this paper,the bare hull(calm water resistance and wave resistance)and hull-propellerrudder model...Based on the incompressible RANS equation,the KVLCC1 ship’s resistance field’s numerical simulation is carried out.In this paper,the bare hull(calm water resistance and wave resistance)and hull-propellerrudder models are studied and compared with the values of the Hydrostatic resistance test.In the hull-propeller-rudder system’s performance analysis,the body force method is used to replace the real propeller model.The new calculation domain is set for the hull-propeller-rudder system model and meshed again to obtain the highly reliable numerical simulation results.Finally,the calculation results are analyzed.The research results in this paper can provide technical support for the resistance of similar ship types.展开更多
The dry-gas seal has been widely used in different industries. With increased spin speed of the rotator shaft, turbulence occurs in the gas film between the stator and rotor seal faces. For the micro-scale flow in the...The dry-gas seal has been widely used in different industries. With increased spin speed of the rotator shaft, turbulence occurs in the gas film between the stator and rotor seal faces. For the micro-scale flow in the gas film and grooves, turbulence can change the pressure distribution of the gas film. Hence, the seal performance is influenced. However, turbulence effects and methods for their evaluation are not considered in the existing industrial designs of dry-gas seal. The present paper numerically obtains the turbulent flow fields of a spiral-groove dry-gas seal to analyze turbulence effects on seal performance. The direct numerical simulation （DNS） and Reynolds-averaged Navier-Stokes （RANS） methods are utilized to predict the velocity field properties in the grooves and gas film. The key performance parameter, open force, is obtained by integrating the pressure distribution, and the obtained result is in good agreement with the experimental data of other researchers. Very large velocity gradients are found in the sealing gas film because of the geometrical effects of the grooves. Considering turbulence effects, the calculation results show that both the gas film pressure and open force decrease. The RANS method underestimates the performance, compared with the DNS. The solution of the conventional Reynolds lubrication equation without turbulence effects suffers from significant calculation errors and a small application scope. The present study helps elucidate the physical mechanism of the hydrodynamic effects of grooves for improving and optimizing the industrial design or seal face pattern of a dry-gas seal.展开更多
The roll motions are influenced by significant viscous effects such as the flow separation.The 3D simulations of free decay roll motions for the ship model DTMB 5512 are carried out by Reynold averaged NavierStokes(RA...The roll motions are influenced by significant viscous effects such as the flow separation.The 3D simulations of free decay roll motions for the ship model DTMB 5512 are carried out by Reynold averaged NavierStokes(RANS) method based on the dynamic mesh technique.A new moving mesh technique is adopted and discussed in details for the present simulations.The purpose of the research is to obtain accurate numerical prediction for roll motions with their respective numerical/modeling errors and uncertainties.Errors and uncertainties are estimated by performing the modern verification and validation(V&V) procedures.Simulation results for the free-floating surface combatant are used to calculate the linear,nonlinear damping coefficients and resonant frequencies including a wide range of forward speed.The present work can provide a useful reference to calculate roll damping by computational fluid dynamics(CFD) method and simulate a general ship motions in waves.展开更多
The massively separated flow past triple cylin- ders （TriC） in tandem arrangement is simulated using the improved delayed detached-eddy simulation （IDDES） method based on the shear stress transport （SST） model, ...The massively separated flow past triple cylin- ders （TriC） in tandem arrangement is simulated using the improved delayed detached-eddy simulation （IDDES） method based on the shear stress transport （SST） model, coupled with the high order adaptive dissipation scheme. The spacing between adjacent cylinders is sub-critical （1.435D）. IDDES prediction of two cylinders （TC） with the same spacing is compared to experimental data for validation, and the numerical results agree well with the available measurements, except for the asymmetry in the gap region. The flow past TriC is investigated using the same method. Generally, the mean flow quantities past TriC, such as the velocity, pressure, and vorticity, are similar to the corresponding components of TC. However, the pressure fluctuations on the TriC surface are uniformly larger than those on TC. Meanwhile, the instantaneous flows past TriC are much more complex. The periodical blockage in the first gap region is found in the TriC case and leads to the up-and-down movement of shear layer in the second gap region.展开更多
Environmental effects have an important influence on Offshore Wind Turbine (OWT) power generation efficiency and the structural stability of such turbines. In this study, we use an in-house Boundary Element (BEM)-panM...Environmental effects have an important influence on Offshore Wind Turbine (OWT) power generation efficiency and the structural stability of such turbines. In this study, we use an in-house Boundary Element (BEM)-panMARE code-to simulate the unsteady flow behavior of a full OWT with various combinations of aerodynamic and hydrodynamic loads in the time domain. This code is implemented to simulate potential flows for different applications and is based on a three-dimensional first-order panel method. Three different OWT configurations consisting of a generic 5 MW NREL rotor with three different types of foundations (Monopile, Tripod, and Jacket) are investigated. These three configurations are analyzed using the RANSE solver which is carried out using ANSYS CFX for validating the corresponding results. The simulations are performed under the same environmental atmospheric wind shear and rotor angular velocity, and the wave properties are wave height of 4 m and wave period of 7.16 s. In the present work, wave environmental effects were investigated firstly for the two solvers, and good agreement is achieved. Moreover, pressure distribution in each OWT case is presented, including detailed information about local flow fields. The time history of the forces at inflow direction and its moments around the mudline at each OWT part are presented in a dimensionless form with respect to the mean value of the last three loads and the moment amplitudes obtained from the BEM code, where the contribution of rotor force is lower in the tripod case and higher in the jacket case and the calculated hydrodynamic load that effect on jacket foundation type is lower than other two cases.展开更多
A fully automated optimization process is provided for the design of ducted propellers under open water conditions, including 3D geometry modeling, meshing, optimization algorithm and CFD analysis techniques. The deve...A fully automated optimization process is provided for the design of ducted propellers under open water conditions, including 3D geometry modeling, meshing, optimization algorithm and CFD analysis techniques. The developed process allows the direct integration of a RANSE solver in the design stage. A practical ducted propeller design case study is carried out for validation. Numerical simulations and open water tests are fulfilled and proved that the optimum ducted propeller improves hydrodynamic performance as predicted.展开更多
In order to correct the unphysical log-layer mismatch commonly encountered in detached eddy simulation(DES) of flows with attached boundary layers,a function M,ML,which has a multi-layer structure with scaling laws in...In order to correct the unphysical log-layer mismatch commonly encountered in detached eddy simulation(DES) of flows with attached boundary layers,a function M,ML,which has a multi-layer structure with scaling laws in each layer and a plateau related to the Kármán constant,is defined.The height of this plateau is found to be crucial for obtaining the correct log-layer.A target scaling function is designed which equals M,ML in the near-wall region,but with the height of plateau determined analytically from the classical log-law.This scaling function is used as a target function according to which the resolved turbulent fluctuations are renormalized,in order to recover the height of plateau prescribed by the log-law.The renormalization procedure guarantees the height of M,ML required by log-law,resulting in correct log layer slope.The method is also shown to maintain similar turbulent properties in the large eddy simulation(LES) region of DES method.Hence it predicts the turbulent intensity correctly.The results demonstrate the relationship between constant M,ML and log-law profile of mean velocity,and relate the Kármán constant to turbulent fluctuations,implying a complete description of turbulent structural ensemble dynamics.The proposed method can be extended to more general flows with log layers since it uses only the log-law with Kármán constant as the input,while the intercept of log layer depends on the solution of Spalart-Allmaras(SA) model in the near-wall field,where Reynolds-averaged Navier-Stokes(RANS) solutions are accurate.展开更多
Strongly nonlinear characteristics of ship roll owing to viscous effect can be usually observed. To describe the nonlinear roll behavior, the CFD method has been frequently employed with obvious advantages compared wi...Strongly nonlinear characteristics of ship roll owing to viscous effect can be usually observed. To describe the nonlinear roll behavior, the CFD method has been frequently employed with obvious advantages compared with the traditional semi-empirical formula method in estimating the roll damping. Numerical simulations of free decay and forced rolling at various forward speeds and amplitudes for a 3-D ship hull are conducted in the present research to predict ship roll damping, in which a RANS solver is employed and a dynamic mesh technique is adopted and discussed in detail. Numerical results, including nonlinear flow characters around ships, rolling decay curves and damping coefficients, show that they are all in good agreement with available experimental data. The linear and nonlinear damping coefficients are estimated and analyzed by fitting with exponential functions for various rolling amplitudes, frequencies and speeds in the free decay simulations, and the damping coefficients are obtained by a polynomial fitting in the forced roll simulations. It is indicated that the damping coefficients increase with increasing rolling angle amplitude and velocity. It is also emphasized that the effect of forward speed is significant to roll damping and the nonlinear damping decreases with increasing velocity.展开更多
A hybrid approach coupled with a surface panel method for the propeller and a Reynolds averaged Navier-Stokes（RANS） model for the hull with the propeller body forces are presented for predicting the self-propulsion ...A hybrid approach coupled with a surface panel method for the propeller and a Reynolds averaged Navier-Stokes（RANS） model for the hull with the propeller body forces are presented for predicting the self-propulsion performance and the effective wake field of underwater vehicles. To achieve a high accuracy and simplicity, a radial basis function（RBF） based approach is proposed for mapping the force field from the blade surface panels to the RANS model. The effective wake field is evaluated in two ways, i.e., by extrapolation from the flat planes upstream of the propeller disk, and by direct computation in a curved surface upstream of and parallel to the blade leading edges. The hull-propeller system of a real propeller geometry is further simulated with the sliding mesh model to numerically verify the hybrid approach. Numerical simulations are conducted for the fully appended SUBOFF submarine model. The high accuracy of the RBF-based interpolation scheme is confirmed, and the effective wake fraction predicted by the hybrid approach is found consistent with that obtained by the sliding mesh model. The effective wake fractions predicted by the two methods are, respectively, 4.6% and 3% larger than the nominal one.展开更多
基金The project supported by the National Natural Science Foundation of China (10502030 and 90505005)
文摘This paper presents hybrid Reynolds-averaged Navier-Stokes （RANS） and large-eddy-simulation （LES） methods for the separated flows at high angles of attack around a 6：1 prolate spheroid. The RANS/LES hybrid meth- ods studied in this work include the detached eddy simulation （DES） based on Spalart-Allmaras （S-A）, Menter＇s k-ω shear-stress-transport （SST） and k-o9 with weakly nonlinear eddy viscosity formulation （Wilcox-Durbin＋, WD＋） models and the zonalANS/LES methods based on the SST and WD＋ models. The switch from RANS near the wall to LES in the core flow region is smooth through the implementation of a flow-dependent blending function for the zonal hybrid method. All the hybrid methods are designed to have a RANS mode for the attached flows and have a LES behavior for the separated flows. The main objective of this paper is to apply the hybrid methods for the high Reynolds number separated flows around prolate spheroid at high-incidences. A fourth-order central scheme with fourth-order artificial viscosity is applied for spatial differencing. The fully implicit lower-upper symmetric-Gauss-Seidel with pseudo time sub-iteration is taken as the temporal differentiation. Comparisons with available measurements are carried out for pressure distribution, skin friction, and profiles of velocity, etc. Reasonable agreement with the experiments, accounting for the effect on grids and fundamental turbulence models, is obtained for the separation flows.
基金Project(2020YFF0304103-03) supported by the National Key Research and Development Program of ChinaProject(2020JJ4737) supported by the Natural Science Foundation of Hunan Province,China+1 种基金Project (202045014) supported by the Central University Financial Funds,ChinaProject(P2019J023) supported by the Science and Technology Research Program of China National Railway Group Co.,Ltd。
文摘An investigation of the effect of simplifying bogie regions on the aerodynamic performance of a high-speed train was carried out by studying four train models,to explore possible ways to optimise the train underbody structure,improve the underbody aerodynamic performance,and reduce the aerodynamic drag.The shear stress transport(SST)k-ωturbulence model was used to study the airflow features of the high-speed train with different bogie regions at Re=2.25×10^(6).The calculated aerodynamic drag and surface pressure were compared with the experimental benchmark of wind tunnel tests.The results show that the SST k-ωmodel presents high accuracy in predicting the flow fields around the train,and the numerical results closely agree with the experimental data.Compared with the train with simplified bogies,the aerodynamic drag of the train with a smooth surface and the train with enclosed bogie cavities/inter-carriage gaps decreases by 38.2%and 30.3%,respectively,while it increases by 10.8%for the train with cavities but no bogies.Thus,enclosing bogie cavities shows a good capability of aerodynamic drag reduction for a new generation of highspeed trains.
基金financially supported by the National Natural Science Foundation of China(Grant No.51009087)the National Science Foundation of Shanghai(Grant No.14ZR1419500)
文摘In order to reduce the total resistance of a hull, an optimization framework for the bulbous bow optimization was presented. The total resistance in calm water was selected as the objective function, and the overset mesh technique was used for mesh generation. RANS method was used to calculate the total resistance of the hull. In order to improve the efficiency and smoothness of the geometric reconstruction, the arbitrary shape deformation （ASD） technique was introduced to change the shape of the bulbous bow. To improve the global search ability of the particle swarm optimization （PSO） algorithm, an improved particle swarm optimization （IPSO） algorithm was proposed to set up the optimization model. After a series of optimization analyses, the optimal hull form was found. It can be concluded that the simulation based design framework built in this paper is a promising method for bulbous bow optimization.
文摘Based on the incompressible RANS equation,the KVLCC1 ship’s resistance field’s numerical simulation is carried out.In this paper,the bare hull(calm water resistance and wave resistance)and hull-propellerrudder models are studied and compared with the values of the Hydrostatic resistance test.In the hull-propeller-rudder system’s performance analysis,the body force method is used to replace the real propeller model.The new calculation domain is set for the hull-propeller-rudder system model and meshed again to obtain the highly reliable numerical simulation results.Finally,the calculation results are analyzed.The research results in this paper can provide technical support for the resistance of similar ship types.
基金supported by Scientific Research Foundation for Returned Scholars,Ministry of Education of China
文摘The dry-gas seal has been widely used in different industries. With increased spin speed of the rotator shaft, turbulence occurs in the gas film between the stator and rotor seal faces. For the micro-scale flow in the gas film and grooves, turbulence can change the pressure distribution of the gas film. Hence, the seal performance is influenced. However, turbulence effects and methods for their evaluation are not considered in the existing industrial designs of dry-gas seal. The present paper numerically obtains the turbulent flow fields of a spiral-groove dry-gas seal to analyze turbulence effects on seal performance. The direct numerical simulation （DNS） and Reynolds-averaged Navier-Stokes （RANS） methods are utilized to predict the velocity field properties in the grooves and gas film. The key performance parameter, open force, is obtained by integrating the pressure distribution, and the obtained result is in good agreement with the experimental data of other researchers. Very large velocity gradients are found in the sealing gas film because of the geometrical effects of the grooves. Considering turbulence effects, the calculation results show that both the gas film pressure and open force decrease. The RANS method underestimates the performance, compared with the DNS. The solution of the conventional Reynolds lubrication equation without turbulence effects suffers from significant calculation errors and a small application scope. The present study helps elucidate the physical mechanism of the hydrodynamic effects of grooves for improving and optimizing the industrial design or seal face pattern of a dry-gas seal.
基金the National Natural Science Foundation of China(No.51579147)
文摘The roll motions are influenced by significant viscous effects such as the flow separation.The 3D simulations of free decay roll motions for the ship model DTMB 5512 are carried out by Reynold averaged NavierStokes(RANS) method based on the dynamic mesh technique.A new moving mesh technique is adopted and discussed in details for the present simulations.The purpose of the research is to obtain accurate numerical prediction for roll motions with their respective numerical/modeling errors and uncertainties.Errors and uncertainties are estimated by performing the modern verification and validation(V&V) procedures.Simulation results for the free-floating surface combatant are used to calculate the linear,nonlinear damping coefficients and resonant frequencies including a wide range of forward speed.The present work can provide a useful reference to calculate roll damping by computational fluid dynamics(CFD) method and simulate a general ship motions in waves.
基金supported by the National Natural Science Foundation of China (Grant 11372159)
文摘The massively separated flow past triple cylin- ders （TriC） in tandem arrangement is simulated using the improved delayed detached-eddy simulation （IDDES） method based on the shear stress transport （SST） model, coupled with the high order adaptive dissipation scheme. The spacing between adjacent cylinders is sub-critical （1.435D）. IDDES prediction of two cylinders （TC） with the same spacing is compared to experimental data for validation, and the numerical results agree well with the available measurements, except for the asymmetry in the gap region. The flow past TriC is investigated using the same method. Generally, the mean flow quantities past TriC, such as the velocity, pressure, and vorticity, are similar to the corresponding components of TC. However, the pressure fluctuations on the TriC surface are uniformly larger than those on TC. Meanwhile, the instantaneous flows past TriC are much more complex. The periodical blockage in the first gap region is found in the TriC case and leads to the up-and-down movement of shear layer in the second gap region.
文摘Environmental effects have an important influence on Offshore Wind Turbine (OWT) power generation efficiency and the structural stability of such turbines. In this study, we use an in-house Boundary Element (BEM)-panMARE code-to simulate the unsteady flow behavior of a full OWT with various combinations of aerodynamic and hydrodynamic loads in the time domain. This code is implemented to simulate potential flows for different applications and is based on a three-dimensional first-order panel method. Three different OWT configurations consisting of a generic 5 MW NREL rotor with three different types of foundations (Monopile, Tripod, and Jacket) are investigated. These three configurations are analyzed using the RANSE solver which is carried out using ANSYS CFX for validating the corresponding results. The simulations are performed under the same environmental atmospheric wind shear and rotor angular velocity, and the wave properties are wave height of 4 m and wave period of 7.16 s. In the present work, wave environmental effects were investigated firstly for the two solvers, and good agreement is achieved. Moreover, pressure distribution in each OWT case is presented, including detailed information about local flow fields. The time history of the forces at inflow direction and its moments around the mudline at each OWT part are presented in a dimensionless form with respect to the mean value of the last three loads and the moment amplitudes obtained from the BEM code, where the contribution of rotor force is lower in the tripod case and higher in the jacket case and the calculated hydrodynamic load that effect on jacket foundation type is lower than other two cases.
基金financially supported by the National Natural Science Foundation of China(Grant No.51009090)the State Key Laboratory of Ocean Engineering(Grant No.GKZD010063)
文摘A fully automated optimization process is provided for the design of ducted propellers under open water conditions, including 3D geometry modeling, meshing, optimization algorithm and CFD analysis techniques. The developed process allows the direct integration of a RANSE solver in the design stage. A practical ducted propeller design case study is carried out for validation. Numerical simulations and open water tests are fulfilled and proved that the optimum ducted propeller improves hydrodynamic performance as predicted.
基金supported by the National Natural Science Fund of China(Grant No. 90716008)the National Basic Research Program of China(Grant No. 2009CB72410)
文摘In order to correct the unphysical log-layer mismatch commonly encountered in detached eddy simulation(DES) of flows with attached boundary layers,a function M,ML,which has a multi-layer structure with scaling laws in each layer and a plateau related to the Kármán constant,is defined.The height of this plateau is found to be crucial for obtaining the correct log-layer.A target scaling function is designed which equals M,ML in the near-wall region,but with the height of plateau determined analytically from the classical log-law.This scaling function is used as a target function according to which the resolved turbulent fluctuations are renormalized,in order to recover the height of plateau prescribed by the log-law.The renormalization procedure guarantees the height of M,ML required by log-law,resulting in correct log layer slope.The method is also shown to maintain similar turbulent properties in the large eddy simulation(LES) region of DES method.Hence it predicts the turbulent intensity correctly.The results demonstrate the relationship between constant M,ML and log-law profile of mean velocity,and relate the Kármán constant to turbulent fluctuations,implying a complete description of turbulent structural ensemble dynamics.The proposed method can be extended to more general flows with log layers since it uses only the log-law with Kármán constant as the input,while the intercept of log layer depends on the solution of Spalart-Allmaras(SA) model in the near-wall field,where Reynolds-averaged Navier-Stokes(RANS) solutions are accurate.
基金Project supported by the National Natural Science Foundation of China(Grant No.50639020)the National High Technology Research and Development Program of China(863Program,Grant No.2006AA09Z332)
文摘Strongly nonlinear characteristics of ship roll owing to viscous effect can be usually observed. To describe the nonlinear roll behavior, the CFD method has been frequently employed with obvious advantages compared with the traditional semi-empirical formula method in estimating the roll damping. Numerical simulations of free decay and forced rolling at various forward speeds and amplitudes for a 3-D ship hull are conducted in the present research to predict ship roll damping, in which a RANS solver is employed and a dynamic mesh technique is adopted and discussed in detail. Numerical results, including nonlinear flow characters around ships, rolling decay curves and damping coefficients, show that they are all in good agreement with available experimental data. The linear and nonlinear damping coefficients are estimated and analyzed by fitting with exponential functions for various rolling amplitudes, frequencies and speeds in the free decay simulations, and the damping coefficients are obtained by a polynomial fitting in the forced roll simulations. It is indicated that the damping coefficients increase with increasing rolling angle amplitude and velocity. It is also emphasized that the effect of forward speed is significant to roll damping and the nonlinear damping decreases with increasing velocity.
基金Project supported by the National Basic Research Development Program of China(973 Program,Grant No.613134)
文摘A hybrid approach coupled with a surface panel method for the propeller and a Reynolds averaged Navier-Stokes（RANS） model for the hull with the propeller body forces are presented for predicting the self-propulsion performance and the effective wake field of underwater vehicles. To achieve a high accuracy and simplicity, a radial basis function（RBF） based approach is proposed for mapping the force field from the blade surface panels to the RANS model. The effective wake field is evaluated in two ways, i.e., by extrapolation from the flat planes upstream of the propeller disk, and by direct computation in a curved surface upstream of and parallel to the blade leading edges. The hull-propeller system of a real propeller geometry is further simulated with the sliding mesh model to numerically verify the hybrid approach. Numerical simulations are conducted for the fully appended SUBOFF submarine model. The high accuracy of the RBF-based interpolation scheme is confirmed, and the effective wake fraction predicted by the hybrid approach is found consistent with that obtained by the sliding mesh model. The effective wake fractions predicted by the two methods are, respectively, 4.6% and 3% larger than the nominal one.
