三角翼大迎角绕流特性数值模拟的网格处理技术研究  

Study on Grid Generation of Numerical Simulation for Vortical Flow over a Delta Wing at High Angle of Attack

作　　者：李沛峰[1] 张彬乾[1] 

机构地区：[1]西北工业大学航空学院,陕西西安710072

出　　处：《航空计算技术》2008年第2期22-26,共5页Aeronautical Computing Technique

摘　　要：研究网格对三角翼大迎角绕流特性数值模拟的影响。结果表明,网格的生成需要结合流动现象,对网格拓扑结构和网格点分布进行选择与搭配。C-H型网格适宜模拟尖前缘分离涡流态,法向网格在一定范围内应等距增长,沿流向逆压梯度较大的区域内适当增加网格点,尾迹区网格则应做上翘处理。Euler方程具有模拟三角翼旋涡及预测涡破裂特性的能力,但对二次涡等粘性引起的流动细节把握能力不足。利用层流假设的N-S方程,通过合适的网格,也可得到满意的计算结果,但对涡破裂后的强烈非定常湍流流动模拟能力不足。采用旋涡螺旋度可准确反映主涡与二次涡流动,描述旋涡的破裂现象。用轴向速度迅速减小并小于来流速度的点作为涡破裂判据似应更合理。This paper analyzes grid influence in simulating vortex flow over delta wing at high angle of attack by the CFD method. The grid topology and grid points distribution should be based on flow phenomena during the grid generation process. The C- H topology is suitable for simulating vortex flow, grid points distribution on the wing surface, vortical flow and wake flow region play an important role in capturing flow details. Euler method is capable of simulating vortical flow and vortex breakdown, but it does not feature the secondary separation and flow details which are induced by viscous effect. Laminar N- S method shows better result, however, it has limitation in simulating strong unsteady turbulence flow in vortex breakdown region. The helicity can exactly describe the primary and secondary vortex flow, and can identify the vortex breakdown. The vortex burst point judgment, which is defined by the axial station where the axial velocity of the vortex core decelerates raoidly and becomes less than uoward uniform flow.seems to he more reasonable.

关 键 词：三角翼 大迎角 网格 数值模拟 旋涡破裂 

分 类 号：V211.3[航空宇航科学与技术—航空宇航推进理论与工程]