关键词: 温度梯度;压力梯度;密度梯度;边界层转捩;数值仿真

Abstract: To investigate the influence of high temperature gradient on transition in boundary layer,Coupland′s T3 flat plate experiments at zero and non-zero pressure gradient are adapted with different temperature gradient in boundary layer by numerical simulation,and are validated by experiments.The results show that the higher temperature gradient can delay transition process and postpone the onset location of transition to backward position,wall skin-friction coefficient and shape factor of boundary layer with temperature gradient are higher than that with no temperature gradient in the same place of plate.The turbulent pulse of mainstream is weakened because of density gradient caused by temperature gradient.The turbulent energy is dissipated by the vertical buoyancy caused by the density gradient in boundary layer.The influence on transition by temperature gradient is weaker than mainstream hydrokinetics properties,such as turbulence intensity,inlet velocity and pressure gradient.

Key words: Temperature gradient;Pressure gradient;Density gradient,Boundary layer transition;Numerical simulation