Experimental investigation of flow around a 45° oriented cube for Reynolds numbers between 500 and 50 000

Flow around an oriented cube is experimentally studied using particle image velocimetry measurements. The cube is rigidly suspended and oriented at an angle of 45 degrees with respect to the freestream flow. Instantaneous and mean flow fields in the wake have been examined at 16 different values of Reynolds numbers between 500 and 50 000. Vorticity identified using swirling strength shows a chaotic wake at higher Re. A wider wake and a longer wake length are noted as compared to flow around a normal cube. The wake width collapses to nearly the same value for all Re beyond the wake length. Unlike a cube, an oriented cube has a recirculation region with multiple peaks for velocity deficit, which is a signature of many smaller eddies present in the wake. The range of investigated Reynolds numbers shows behavioral changes in the wake, hinting at the possibility of critical Reynolds numbers (or different regimes) based on a maximum velocity deficit, maximum vorticity magnitude, and energy content of the first mode extracted using proper orthogonal decomposition. Proper orthogonal decomposition has been used to understand the contribution of different modes in the formation of coherent structures in the wake. An oriented cube is an extreme case for nonspherical objects and has marked differences from the wake of a cube and other regular-shaped objects. The present work is an attempt to provide an understanding of and improve upon the scarce investigation performed for the wake of an oriented cube.

Automated summary

Experimental study on flow around an oriented cube reveals chaotic wake at higher Reynolds numbers, with wider and longer wake compared to a normal cube. Unlike a cube, an oriented cube shows multiple peaks for velocity deficit in the recirculation region, indicating presence of smaller eddies in the wake. Investigated Reynolds numbers suggest behavioral changes in the wake, hinting at the possibility of critical Reynolds numbers based on different parameters.