【摘要】 利用氢气泡流动显示方法 ,研究人工激发条件下平板边界层转捩的流动现象。实验观测到转捩过程中的尖峰结构 (spikestructure) ,以往这一现象都是热线 (膜 )测量得到的。流动显示结果证明了关于尖峰现象的推测 ,即尖峰的出现是环状涡对其中心速度诱导的结果 ,同时观测到伴随高频尖峰结构的出现 ,边界层内流动开始紊乱化更多还原

【Abstract】 By use of hydrogen bubble visualization method, flow evolutions are studied in an artificially excited transitional boundary layer on a flat plate. Spike structures are observed, which were only detected before by means of hot wire (film) anemometry. The results verify one of guesses about the formation of spike structures: spike is results of abrupt local velocity fluctuation induced by ring like structures, which are evolved form upstream hairpin vortex. It is also shown that together with the appearance of high frequency spikes, flow breakdown begins to take place.更多还原