Modeling unsteady boundary layer transition on a curved plate under periodic unsteady flow conditions: Aerodynamic and heat transfer investigations

A boundary layer transition model is developed that accounts for the effect s of periodic unsteady wake flow on the boundary layer transition. To estab lish the model, comprehensive unsteady boundary layer and heat transfer exp erimental investigations are conducted. The experiments are performed on a curved plate at zero-streamwise pressure gradient under periodic unsteady w ake flow, where the frequency of the periodic unsteady flow is varied. The analysis of the time-dependent velocities, turbulence intensities, and turb ulence intermittencies has identified three distinct quantities as primaril y responsible for the transition of an unsteady boundary layer. These quant ities, which exhibit the basis of the transition model presented in this pa per, are: 1) relative intermittency (2) maximum intermittency, and (3) mini mum intermittency To validate the developed transition model, it is impleme nted in an existing boundary layer code, and the resulting velocity profile s and the heat transfer coefficients are compared with the experimental dat a.