Numerical study of turbulent round jet in a uniform counterflow using a second order Reynolds Stress Model

A turbulent round jet issuing into a uniform counterflow stream is computationally investigated together with comparison with earlier experiments data, including velocity component along the jet axis and the radial direction. The simulation is carried out using the Reynolds Stress Model (RSM). Numerical results agree well with experimental results and the penetration and spreading of the jet are studied. The turbulence feature of the counterflowing jet indicates that the root-mean-square (rms) of axial velocity fluctuation (root u'(2)) has two distinct peaks whose the second is a specificity of the jet into a counterflow, located within the region near the stagnation point. As the centerline velocity, the centerline temperature is found to decay more rapid when the jet-to-current velocity ratio is smaller. The spreading of the jet is also interpreted by the growth of both momentum width and temperature width of the counterflowing jet leading to that the presence of a counterflow enhances the mixing of the jet. (C) 2015 International Association for Hydro-environment Engineering and Research, Asia Pacific Division. Published by Elsevier B.V. All rights reserved.