Turbulent Shear Flow and Heat Transfer Over the Repeated Two-Dimensional Square Ribs on Ground Plane

Abstract

This paper describes the flow structure over the repeated two-dimensional square ribs of side length D , placed at a pitch S on a ground plane. The value of S/D which most augments the turbulence of the free stream and, hence the heat transfer is calculated. The region of interest in this investigation is far downstream where the velocity and temperature distributions follow similarity rules. The time-mean velocity, static pressure, and the velocity vectors were measured by Pivot-and static pressure tubes and a three hole cylindrical yawmeter. The turbulence intensities and integral scale were obtained using a hot wire anemometer. The mean temperature distribution was measured by thermocouples and the local heat transfer coefficient was then calculated. It is found that at S/D=9 the turbulence intensity is maximized. As a result of this effect and the fact that for S/D=9 the flow reattaches within a groove, the heat transfer is also maximized. The measurements show how the location of reattachment depends on S/D and that high local heat transfer coefficient coincides with the reattachment point. The average heat transfer coefficient and the pressure drop correlation is quantified.