Experimental study on turbulent mixing process in cross-flow type T-junction

This study was conducted to clarify how two fluids with different temperature are mixed turbulently in a cross-flow type T-junction. The characteristics of the velocity and temperature fields in the channel were investigated experimentally, and the flow visualization was conducted to make clear the detailed behavior of the interface between two flows in the flow-merging region. We extracted the dominant structures of the velocity and concentration fields by proper orthogonal decomposition (POD). It is clarified that the interface of two flows is oscillating vertically and several discrete longitudinal eddies are superposed on it. We have concluded that the vertical oscillation of the interface is caused by the fluctuation of the streamwise velocity component, and the mushroom-like eddies are caused by the vertical fluctuating velocity; the former produces the turbulent heat flux in the streamwise direction, and the latter produces that in the vertical direction.