Experimental study of flow in a cavity with the variable shape at a low Reynolds number

Abstract

Abstract The flow structure of a cavity with a length-to-depth ratio of 2:1. In this experiment, the particle image velocimetry (PIV) technique was used to experimentally research the front and rear wall inclined cavity configurations with different inclinations. The experiments were carried out in a recirculating water tank. The configurations with front and rear wall inclination angles of 26°, 45°, and 56° were compared at the same incoming flow velocity. A total of seven different configurations are given for the comparison of several variables. In addition, the flow velocity, Reynolds stress and turbulence intensity values were measured and analyzed for all configurations. Correlation analysis is used to reveal the shear layer evolution process, and the outcomes indicate that the wall inclination changes the shape and size of the shear layer. The coherent structures of shear layers with different cavity shapes are identified in combination with appropriate proper orthogonal decomposition (POD). Different shapes of the cavity configuration may vary the size of the shear layer. The calculation of turbulence intensity also shows that the cavity configuration with the largest inclination angle has the largest cavity turbulence intensity at the centreline cross-section.