NUMERICAL SIMULATION OF SEPARATION BUBBLE ON ELLIPTIC CYLINDERS USING THREE-EQUATION K -ω TURBULENCE MODEL

Occurrence of laminar separation bubbles on solid walls of an elliptic cylinder has been simulated using a recently developed transitional model for boundary layer ows Computational method is based on the solution of the Reynolds Averaged Navier Stokes RANS equations and the eddy viscosity concept Transitional model tries to simulate streamwise uctuations induced by freestream turbulence in pre transitional boundary layer ows by introducing an additional transport equation for laminar kinetic energy term It includes three transport equations of turbulent kinetic energy KT laminar kinetic energy KL and dissipation rate frequency Numerical results show that the model is capable of predicting each of the subcritical nal separation in laminar critical existence of bubble bubbles and supercritical nal separation in turbulent ow regimes Laminar separation bubble is simulated precisely due to the modeling of transition from laminar to turbulent in separated free shear layer Separation bubble region and its characteristics were detected by inspection of the distributions of surface pressure and skin friction and also through streamlines pattern Excellent agreements were observed between results obtained through current mathematical modeling and available experimental data for all the ow regimes In addition some of the results of the present numerical method are compared to those obtained from application of conventional fully laminar and fully turbulent standard k models