Estudo experimental do escoamento ao redor de cilindros de base quadrada com diferentes razões de aspecto montados sobre uma superfície

Abstract

The present work has as objective the experimental study using the wind tunnel, flow around the square base cylinders with different aspect ratios (AR), varies from AR to 1 to 4, applying methods to understand the aerodynamic aspects of the problem. Initially, drag characteristics were shown and compared between four aspect ratios studied, obtaining a quadratic trend of increasing drag force with increased speed, and increased drag force with increased expected aspect ratio. The drag coefficient also increased from one body to another, but practically didn’t vary within the available Reynolds range, 5.91x10^4 a 13.01x10^4. Later, velocity profile was evaluated, by using hot wire anemometer, with Re = 9,46x10^4, in a region of interest in the back of the body and it was noted that the increased aspect ratio changed the speed profile characteristic, change observed in the transition from AR 2 to AR3 , suggesting that there is a critical aspect ratio, between 2 and 3, wich differs the flow behavior in the analyzed region. Pressure distribution was performed on the square base cylinder faces, maintaining Re = 9,46x10^4, where they showed interference from the base region, lateral corners and free-end surface. Finally, experimental visualization techniques were performed, evidencing presupposed characteristics and increasing the fidelity of previous analyzes and conclusions. Future studies focusing on the posterior region of the body, in addition to a computational numerical comparison, are recommended