Reza Taghavi-Zenouz - Assistant Professor, Department of Mechanical Engineering , Iran University of Science and Technology
Majed Etemadi - Ph.D. students
Mahmood Salari - Ph.D. students

Occurrence of laminar separation bubbles on solid walls of an elliptic cylinder has been simulated using a recently developed transitional model for boundary layer flows. This model is a new approach to the Raynolds averaged Navier-Stokes equations utilizing eddy-viscosity concept including three transport equations of turbulent kinetic energy, KT, laminar kinetic energy, KL, and dissipation rate frequency, ω. The proposed mathematical model is capable of predicting each of subcritical (final separation in laminar), critical (existence of bubble/bubbles) and supercritical (final separation in turbulent) flow regimes. Bubble occurrence is simulated precisely, due to modeling of transition from laminar to turbulent in separated free shear layer. This, in turn, has caused the separated laminar flow to re-attach to the surface and form a bubble, which can highly affect the characteristics of the flow field. Separation bubble region was detected by inspection of the pressure distribution over the solid walls, in which it is initially constant and then increases suddenly. Results of the present numerical method are compared to those obtained through application of conventional fully laminar and fully turbulent standard k-ω models.

Boundary Layer Laminar Separation Bubble, Eddy-viscose Model, Blunt Body