翼型绕流的多级分辨率光滑粒子流体动力学数值模拟研究

Study on the vidcous flow around foils with a multi-resolutionsmooth particle hydrodynamics method

应用考虑流场真实黏性的多级粒子分辨率光滑粒子流体动力学(smoothed particle hydrodynamics,SPH)方法对不同雷诺数下的翼型绕流问题开展了数值模拟和验证。在SPH粒子法框架中实现拉格朗日拟序结构可视化,实现漩涡细节的重现。针对SPH模拟高雷诺数翼型绕流时出现的数值不稳定性,采用张力不稳定性控制技术和粒子位移修正技术加以克服,提高了压力与速度场的计算精度。计算结果表明:SPH方法能够实现翼型绕流问题速度场与压力场的精确计算,并进行良好的受力监测与预报。相对于传统基于欧拉涡量场的漩涡捕捉方法,SPH方法中捕捉的拉格朗日拟序结构也能有效地呈现流场漩涡特征和演化过程,说明SPH方法在模拟考虑真实黏性边界层和漩涡运动的流体动力学问题研究中具有一定的特色。此外,拍动翼型绕流的数值模拟结果还体现了SPH方法在处理带运动边界绕流问题的便利性。

Considering the real viscosity of the fluid,the multi-resolution smooth particle hydrodynamics method is applied to numerically simulate and verify the flow around the foils at different Reynold numbers.In the framework of SPH,the Lagrangian coherent structure can be easily visualized,thus the details of the vortex can be reproduced.In order to overcome the SPH numerical instability when simulating the flow around airfoil at high Reynolds number,the tension instability control and the particle shifting techniques are adopted,thus the numerical accuracy of the pressure and velocity fields are much improved.The analysis of the flow around the foil shows that the SPH method can accurately calculate the velocity and pressure fields,and perform good force monitoring and prediction.In addition,compared to the traditional vortex capturing method based on Euler velocity field,the Lagrangian coherent structure can also effectively reveal the characteristics and the evolution of vortex.The study indicates that the SPH method owns distinguished advantages in the simulation of fluid dynamics problems considering the real viscous boundary layer and vortex motion.In addition,the investigation of the flow around flapping foil demonstrates the capability of the SPH method for simulation with moving boundaries.