Turbulent Flow Over a Plane Symmetric Sudden Expansion

Abstract

Turbulent flow with separation and recirculation over a double backward facing step has been investigated experimentally. Time mean stream wise, transverse and cross-stream components of the velocity fluctuations, together with turbulence kinetic energy and Reynolds shear stresses, were measured using a laser Doppler anemometer, operating in the differential Doppler mode with forward scattering. Ordinary tap water was used in a closed loop flow system with a Reynolds number of 30,210 and significant changes of flow patterns, increases in turbulence kinetic energy, velocity fluctuations and shear stresses were observed downstream of the step expansion.