Prediction Of Hydrodynamic Performance On Three-dimensional Hydrofoil And Propeller Using Potential Panel Method

With the rapid development of shipping industry and computational fluid dynamics,hydrofoils and propellers,as the widely used hydrodynamic devices has made continuous progress.The application of numerical theory method can be more flexible in designing the hydrofoils and propellers.The fast and accurate prediction of hydrodynamic performance using numerical theory method can avoid the noise,vibration and cavitation caused by design defects.The numerical theory method can improve the hydrodynamic performance and efficiency,and it also has the advantage of economical efficiency and rapidity.Therefore,fast and accurate hydrodynamic performance prediction and analysis of hydrofoils and propellers using numerical theory method is very important and practical.Panel method is a numerical calculation method on the actual surface using boundary condition.Panel method can accurately describe the complex surface shape of hydrofoil and propeller.By the establishment of accurate parametric mathematical model,it is easier to do the parametric design.For the numerical calculation of hydrofoil,panel method can make quick and accurate prediction of coefficients of lift,drag,moment and pressure distribution on the surface.For the numerical calculation of propeller,panel method can make prediction of hydrodynamic performance of coefficients of thrust,torque and pressure.With the rapid development of panel method,it is used to predict the hydrodynamic performance of propeller by more and more foreign research institutions.In this paper,a potential panel method based on the combination of two singularity elements is proposed,which is different from the common vortex distribution velocity panel method of single singularity element,and a B-spline curve interpolation method is added to the interpolation of the corner points and collocation points to ensure the accuracy and continuity of interpolation points.In this paper,B-spline interpolation is also used for the distribution of the singularity elements on the complex surface,which ensures the continuity of the results of the singularity point intensity and reduces the possibility of the abrupt change of the surface velocity potential to a certain extent.The surface pressure coefficient and lift performance of the two-dimensional hydrofoil are calculated and analyzed by the above numerical method.The results are compared with the experimental data.In addition to the hydrodynamic performance of the three-dimensional hydrofoil,the hydrodynamic performance of the sweepback hydrofoil and dihedral hydrofoil with the different aspect ratio are analyzed.The steady-state hydrodynamic performance and unsteady hydrodynamic performance of the underwater helicopter are estimated by using the panel method,which verifies the rationality and feasibility of the design.Finally,the surface pressure distribution,the coefficient of thrust and torque of different propellers are calculated and compared with the experimental data.The comparison results are satisfactory.The results of this study provide a basis for estimating the hydrodynamic performance of hydrofoil and propeller by B-spline interpolation of potential panel method.It is practical and important to improve the accuracy of hydrodynamic performance prediction by using the panel method.