Local laminarization in a channel with a small narrowing and a heated wall
A.Yu. Sakhnov
Kutateladze Institute of Thermophysics SB RAS, Novosibirsk,Russia
Keywords: boundary layer, heat transfer, laminarization, velocity sweep, numerical modeling, negative pressure gradient
Abstract
The article presents the results of numerical simulation of the boundary layer of air on a heated surface in the presence of weak acceleration. The numerical model consists of a system of Prandtl equations describing dynamic and thermal processes in the boundary layer, and a κ-ω-γ turbulence model that allows reasonably simulating the laminar-turbulent transition and turbulence suppression. Finite-difference methods were used to solve differential equations. For some calculated cases, the turbulence model was switched off in order to obtain parameters of a known laminar flow. Modeling has shown that in the considered flow conditions, the occurrence and development of a local laminarized region near the wall is possible. In this case, the boundary layer includes the near-wall laminar and external turbulent sections. This nature of the flow leads to a level of friction and heat exchange that correspond to the intermediate flow relative to laminar and turbulent flows under the same conditions.
|
