Effect of spacing ration on flow over repeated two-dimensional square ribs on ground plane

摘要

This paper describes a detailed study of the flow structure over repeated two dimensional square ribs on a ground plane for various values of S/D, and the optimum value of S/D to augment the turbulence intensity near the ground plane. The pitch between the centers of two adjoining square ribs was varied at S/D ＝ 2, 3, 5, 7, 9, 11, 13 and 17. The time mean velocity and turbulence intensity were measured by Laser Doppler Velocimeter. The static pressure was measured by Pitot static tubes. As a result, it is concluded that the pitch ratio S/D ＝ 9 is optimum to augment the turbulence intensity in the groove between two adjoining square ribs, when the two dimensional square ribs are aligned on the wall as a heat transfer promoter.