Comparison of two low-Reynolds number turbulence models for fluid flow study of wall bounded jets

Abstract

A comparative study of flow field and turbulence characteristics of a turbulent offset jet has been done. The computational results obtained from low-Reynolds number k–ϵ models proposed by Launder and Sharma, and Yang and Shih are compared with that of the standard k–ϵ model. The existence of Moffatt vortices (secondary recirculation region) have been identified near the corner of the wall for low-Reynolds number modeling. A velocity similarity profile has been observed as expected due to the resemblance of an offset jet with that of the wall jet flow in the wall jet region. The linear law of the wall (u+=y+) has been found to be valid up to y+≈3.0 in the wall jet region which agrees with the experimental results. The integral constant of momentum flux is higher for lower offset ratio due to a smaller recirculation region. The distribution of pressure field, Reynolds shear stress, budget of turbulent kinetic energy in the recirculation region and the jet characteristic parameters such as variation of the jet half-width (Y0.5) along the streamwise direction and decay of the maximum streamwise velocity are discussed in detail.