空气动力学学报2019，Vol.37Issue(4)：522-529,8.DOI:10.7638/kqdlxxb-2019.0015
高超声速三维边界层横流转捩的数值研究
Numerical study on cross﹣flow transition in three﹣dimensional hypersonic boundary layers
摘要
Abstract
Cross-flow instability is the main transition mechanism in three-dimensional hypersonic boundary layers.However,up to now,there are few numerical investigations on the breakdown process to turbulence for hypersonic boundary layers induced by cross-flow instability. In this paper,the boundary-layer transition is investigated for a blunted flat plate with Mach number 6 and sweep angle of 45 deg.Direct numerical simulations are performed for the linear and nonlinear evolution of stationary cross-flow vortex,as well as the development of the second instability waves on the saturated mean flow,and the transition to turbulence.The results show that the modification of the mean flow caused by the nonlinear effect of the stationary vortices can lead to the rise of the wall friction coefficient curve.However,without introducing the secondary instability waves,the wall friction coefficient stay constant and cannot rise to the value of turbulence level.The introduced high frequency secondary instability waves grow dramatically, and the low frequency disturbances,including stationary ones,which are generated due to the nonlinear interaction,amplify significantly as well.As a result,the mean flow is modified rapidly,leading to a steep rise in the wall friction coefficient.Following that,the saturated cross-flow vortex structure breaks down,and the flow transitions to turbulence.关键词
高超声速边界层/横流/转捩/二次失稳Key words
hypersonic boundary layers/cross-flow/transition/secondary instability分类
数理科学引用本文复制引用
韩宇峰,马绍贤,苏彩虹..高超声速三维边界层横流转捩的数值研究[J].空气动力学学报,2019,37(4):522-529,8.基金项目
国家自然科学基金项目(11472188) （11472188）
