FLOW STRUCTURES IN THE WAKE REGION OF AN L-SHAPED CYLINDER AND A TRIANGULAR CYLINDER

Abstract

Researchers have been intrigued by the flow properties and wake structures behind bluff bodies for years, driven by the varied applications of these bodies in engineering and industry. In this study, flow structures and the downstream wake behind a triangular cylinder (TC) and an L-shaped cylinder (LSC) have been studied experimentally at Reynolds number of 18,100. Constant-temperature hot-wire anemometers were employed to quantitatively measure the near wake properties in terms of velocity components and turbulent kinetic energy (TKE), and similarities and dissimilarities in coherent structure have been addressed in detail quantitatively for the first time. It was found that the wake region behind the LSC exhibits a delay in wake recovery in comparison to the TC. In other words, the dominant status of the vortex shedding phenomena occurs at a higher x/D for LSC in comparison to the TC. The coherent TKE peak of an LSC is about 22% lower than the coherent TKE peak of the TC in the near wake region while on average it is about 20% higher in the far wake region. Finally, it was found that the maximum coherent TKE peak of LSCs occurs at a larger x/D ratio, which can be concluded as an indication of a location delay in the wake region in comparison with the TC case.