基于浸入边界法的扑翼飞行数值模拟

本文提出了基于浸入边界法的扑翼鸟建模与仿真，首先检验了数值方法的精确性，而后对NACA 0012翼型的升沉运动与俯仰运动进行了研究，最后对三维扑翼的翅膀拍动时间非对称性进行了研究。结果表明：浸入边界法对拍动翼型的模拟能够很好地和文献结果吻合。升沉运动的推进能力由翼型前缘涡的大小和位置决定，升沉运动推进效率的峰值主要集中在0.3≤St≤0.4时。升沉运动耦合俯仰运动时，在俯仰角25°及相位差85°时，推进效率达到峰值。在三维模拟中，适当增加翅膀下拍速度，能提供更大的升力，同时耗能也更高。研究结果可以为微型扑翼飞行器的扑动参数设置提供参考。

NUMERICAL SIMULATION OF FLAPPING WING FLIGHT BASED ON IMMERSION BOUNDARY METHOD

In this paper, we propose the modeling and simulation of a flapping bird based on the immersion boundary method. Firstly, the accuracy of the numerical method is tested. And then the heave motion and pitch motion of the NACA 0012 airfoil are studied. Finally, the effect of asymmetry flapping time of a three-dimensional flapping wing is studied. The results show that the simulation of flapping airfoil by immersion boundary method is in good agreement with available results in the literature. The propulsive capacity of heave motion is determined by the size and position of the leading edge vorticity of the airfoil. The peak value of the propulsive efficiency of heave motion is mainly concentrated when 0.3≤St≤0.4. When the heave motion is coupled with the pitch motion, the propulsive efficiency reaches its peak when the pitch angle is 25° and the phase difference is 85°. The results from 3D simulations reveal that appropriately increasing the downbeat speed of the wings provides more lift and consumes more energy. The research results can provide reference for flutter parameter setting of micro flapping wing aircraft.