Experimental Study on a Three-Dimensional Wall Jet (Flow Field in a Cross-Section of Developed Region)

Abstract

This study is to clarify the flow structure of a three-dimensional wall jet discharged tangentially on a flat surface from a circular nozzle. Distributions of the mean velocities and fluctuating velocities in a cross section of a fully-developed flow region were measured by using a single hot-wire probe and cross-wire probes. It is confirmed in any position of the lateral direction that the distributions of the mean velocities U and W in the direction normal to the wall are made similar to each other when they are made dimensionless by the maximum local velocity while the jet height remains almost invariable in the spanwise direction. The direction of the mean flow vector in the inner layer is remained constant while the direction of the mean flow vector outside the half-value height is coincided with the direction of the jet axis. The distributions of the turbulent statistics in the direction normal to the wall are almost similar to each other outside the half-value height due to the scaling by the maximum local velocity, and on the other hand, the magnitude of the turbulent energy and Reynolds stress in the wall-side region becomes larger at the position farther from the jet axis.