Modeling of hypersonic three-dimensional boundary layer transition using a criteria-based method

A new method used for hypersonic three-dimensional boundary layer transition prediction is developed in this paper. It is based on criterion Re_θ/M_e for streanwise instability and criterion Re_cf,new for crossflow instability. An intermittency function is also formulated and applied to combine laminar and turbulent flows. In addition, a computational grid pretreating method is proposed, which is compatible with modern CFD techniques based on unstructured grids and massive parallel execution. Thus, the boundary layer parameters, such as boundary layer thickness, boundary layer edge Mach number, maximum crossflow velocity, etc., could be obtained quickly and effectively. A HIFiRE-5 elliptic cone at different Reynolds number is used to validate the performance of the criteria-based transition model. Results show that the computed Re_θ/M_e and Re_cf,new distributions are similar to the N-factor for streamwise instability and crossflow instability from linear parabolized stability equation methods correspondingly. The shape and trend of transition onsets predicted by the criteriabased transition model between the centerline and the leading edge of HIFiRE-5 also agree well with the experiment. However, as for transition along the centerline which is dominated by inflection point in streamwise velocity profiles, using criteria-based transition model related to boundary layer thickness could predict transition onset prematurely.