| Hybrid RANS/LES methodology | |
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Hybrid RANS/LES methods are an attractive approach for turbulence modelling. We are working on DES (Detached Eddy Simulation) which falls under the category of hybrid RANS/LES methods. Simpler and more versatile DES formulations are being explored which would allow the incorporation of several advances in LES modelling leading to a robust DES methodology. |
| Bypass transition model based on the intermittency function | |
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A bypass transition model is proposed based on the intermittency transport equation in RANS computations. It is formulated in local variables and transition is initiated by diffusion of free stream disturbances into the boundary layer. Other transition modes, like separation and roughness induced transition, are also taken into account. |
| Direct numerical simulation of mixed mode transition | |
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Boundary layer transition from receptivity stage evolves through orderly Tollmien-Schlichting (TS) waves or Bypass routes. Flow regimes exist where either of these modes may be instigated but neither triggers transition. Interaction of modes may cause early transition. We are studying mode interaction of boundary layer streaks and 2D TS waves by invoking free stream turbulence and TS wave disturbances at the inlet. Unlike previous studies, evolution of instability is not set by monochromatic forcing. |