NUMERICAL MODELING OF LAMINAR-TURBULENT TRANSITION IN THE BOUNDARY-LAYERS UNDER THE INFLUENCE OF LOW FREE-STREAM TURBULENCE INTENSITIES

Predictions of laminar-turbulent transition in the two-dimensional and axisymmetric boundary layers under the influence of low free-stream turbulence levels are presented. A 'near-wall' version of the k-epsilon turbulence model is used for simulation of turbulent transport. The calculations are based on Patankar and Spalding's finite difference algorithm. It is known that for high free-stream turbulence levels, the k-epsilon model simulates the transition well but it fails for low ones. In the present work, calculations are successfully, made for low turbulence levels using Abu-Ghannam and Shaw's correlation for determination of the flow transition point and Dhawan and Narasimha's intermittency factor in the transition zone. The examples include various levels of free-stream turbulence as well as a variety of boundary layers on a rotary ellipsoid. The numerical results are compared with experimental data and the agreement is good.