自由流单位Re数对边界层转捩的影响

FREE-STREAM UNIT REYNOLDS NUMBERS ON THE INFLUENCE OF BOUNDARY-LAYER TRANSITION

利用激波管实验原理和实验技术,在截面为94 ×94mm^2的激波管实验段中,测量了自由流单位Re数单一变化时壁面边界层转捩Re数的变化规律。为此研制了一种可直接显示边界层从层流向湍流过渡全过程的热电模拟网络。根据大量测量结果,并以自由流单位Re数为自变量,整理出预测平板边界层转捩Re数的经验公式。

Under the condition that the incident shock Mach number is fixed , the variation of the transition Reynolds number of boundary layer on the shock tube walls only as a function of the free-stream unit Reynolds number is investigated in this paper. The test section of the shock tube is 1.7 metres in length and its cross-section is a square with side length of 94 mm. Moreover, an elaborate analog circuit which can directly show the complete transition process from laminar to turbulent boundary layers has been made. From the measured values, an empirical formula to predict boundary layer transition Reynolds number for a flat plate or shock tube wall at varying free-stream unit Reynolds number has been obtained.