Reynolds number and end-wall effects on a lid-driven cavity flow

Abstract

A series of experiments has been conducted in a lid‐driven cavity of square cross section (depth=width=150 mm) for Reynolds numbers (Re, based on lid speed and cavity width) between 3200 and 10 000, and spanwise aspect ratios (SAR) between 0.25:1 and 1:1. Flow visualization using polystyrene beads and two‐dimensional laser‐Doppler anemometer (LDA) measurements have shed new light on the momentum transfer processes within the cavity. This paper focuses on the variation, with Re and SAR, of the mean and the rms velocities profiles, as well as the ∼(U ’ V ’) profile, along the horizontal and vertical centerlines in the symmetry plane. In addition, the contribution of the large‐scale ‘‘organized structures,’’ and the high‐frequency ‘‘turbulent’’ velocity fluctuations to the total rms is examined. At low Re, the organized structures account for most of the energy contained in the flow irrespective of SAR. As the Re increases, however, so does the energy content of the higher frequency fluctuations. This trend is not independent of SAR; a reduction in the SAR causes the ‘‘organized structures’’ to again become more evident.