Comparative study of a turbulent wall-attaching offset jet and a plane wall jet

Abstract

The flow field characteristics of a two-dimensional wall-attaching offset jet (WAOJ) are experimentally investigated by comparing with those of a turbulent plane wall jet(PWJ). The mean velocity, the turbulent stresses and triple velocity correlations are measured with a split film probe and anX wire probe. Even with the strong influence of the suction pressure field in the recirculation bubble at the lower corner, it is found that the WAOJ in the wall jet region has a close similarity with the PWJ. Especially, the decay of maximum velocity and the upper jet spread along the maximum velocity line of the WAOJ are virtually the same as those of the PWJ. The mean velocity profile of the WAOJ attains similarity after the jet impingement onto the lower plate. However the profiles of second and third-order moments of fluctuating velocities vary rapidly before the impingement and then relax very slowly to the similarity profiles of the PWJ.