Numerical Study of Two Dimensional Laminar Jet Flow Past a Sudden Expansion

Abstract

A computational study of laminar plane jet flow past a plane symmetric sudden expansion configuration is presented. The dependence of asymmetric flow instability on the velocity profile at the expansion region has been studied. This variation in velocity profile at the expansion region is brought about by varying the length of the inlet duct. The attachment lengths of the jet for a range of Reynolds number (Re) values and aspect ratios (ratio of duct width to jet width) have been presented. An in-house two dimensional incompressible flow code has been developed for solving the problem. The Critical Reynolds Number (Recr) at which jet develops asymmetry with respect to mid-plane of the channel for a certain aspect ratio, increases as the inlet duct length is decreased. Hence, this indicates that the stability of the jet increases with the decrease in the inlet duct length. The shorter attachment length (SAL) remains nearly constant with increase in Re but longer attachment length (LAL) increases with increase in Re for various aspect ratios.