Experimental Investigation on Shape Dependence for Flow past Shallow Cavities

Abstract

Abstract Relative motion between a bluff body having a cavity and the fluid surrounding it causes the fluid flow gets modified due to the presence of the cavity. The properties of flows past cavities are analysed, and various control techniques are devised and employed over the years. The present study aimed at experimentally analysing the flows and their features past three different shapes of cavities i.e., rectangular, hemispherical as well as triangular cavities under similar boundary conditions. The study consists of experimental investigation carried on cavities for similar length-to-depth ratios and the visualization of flow characteristics using a two-dimensional water channel apparatus. In this technique, the free surface of the water stream in the test-section is used in visualizing and analysing the flow characteristics including the formation of vortices, through dye injection, around cavities. The comparative study performed at varying Reynolds number for different cavities indicated the suitability of hemispherical cavities towards creating maximum amount of boundary layer suction.