大迎角振动翼型绕流的数值模拟

NUMERICAL SIMULATION OF FLOWS AROUND OSCILLATING AIRFOIL AT LARGE INCIDENCES

通过对非定常N-S方程的数值求解,研究了最大厚度为12％的Karman-Trafftz翼型在Re数为1000时的大迎角俯仰振动。其中着重分析了旋涡结构与表面压强分布的关系。数值研究表明,后缘形状、折合频率等对涡结构演化有重要影响。后缘涡顺利地从后缘脱落时,失速涡在上翼面能诱导出较大的吸力。后缘涡在翼面上驻留时,各涡产生复杂的相互干扰,对失速涡在上翼面产生吸力有不利影响。

The starting flows past a pitching oscillation Karmam-Trafftz airfoil with 0.12 relative thickness are investigated by numerical calculations for the unsteady N-S equations at Reynolds number 1 000. The emphasis of this study is put on the relation between the complicated vortex structure and the pressure distribution on the body. It is shown that in the present numerical investigations, the trailing edge shape and the reduced frequency have an important influence on the vortex evolution. A high suction peak is induced by the stall vortex as the trailing edge vortex sheds downstream smoothly. Once the trailing edge vortex stays at the trailing edge the interaction of complex vortex structures occurs and no longer has a beneficial effect on the suction peak induced by the stall vortex.