中文摘要：

研究一种蝴蝶（Morpho peleides）前飞时的气动力特性．在运动重叠网格上数值求解Navier-Stokes方程，对蝴蝶前飞时左、右翅膀的拍动运动以及跟随身体一起的俯仰运动进行计算．结果表明：蝴蝶主要用“阻力原理”作拍动飞行，即平衡身体重量的举力和克服身体阻力的推力均主要由翅膀的阻力提供．蝴蝶翅在下拍中产生很大的瞬态阻力（平行于拍动运动的力），对流动结构分析表明，产生此力的机制如下：每次下拍中产生了一个由前缘涡，翅端涡及起动涡构成的强“涡环”，其包含一个沿拍动方向的射流，产生此射流的反作用力即翅膀的阻力．平衡身体重量的举力主要由翅膀下拍中产生的阻力提供．上拍时（由于身体上仰，上拍实际是向后和向上拍动的），翅也产生阻力，但较下拍时小的多．平衡身体阻力的推力主要由翅膀上拍中产生的阻力提供．

英文摘要：

The aerodynamics force generation of a butterfly （ Morpho peleides） in forward flight was studied, using the method of numerically solving the Navier-Stokes equations in moving overset grids. The results shows that the vertical and thrust forces of the wings, which balances the weight and the body drag, are mainly contributed by the drag of the wings. During the downstroke, a strong ＇ vortex ring＇, consistes of the leading edge vortex, the wing tip vortices and the starting vortex, was generated. The ＇vortex ring＇ containes a jet parallel to the wing flapping direction, and the jet produces a large instantaneous drag. The vertical force is mainly due to the drag of the downstroke. The thrust force is mainly due to the drag of the wings in the upstroke.