The flow dynamics about a cylindrical cactus plant model in cross wind

Abstract

Researchers were in many occasions inspired from the biology field in order to improve engineering systems. Cactus trees are long cylindrical plants with longitudinal grooves. They have survived the harsh dessert environment resisting the strong sand storms despite their weak rooting system. Therefore, they are thought to have an aerodynamic superiority on their counterpart circular cylinders. Particle Imaging Velocimetry (PIV) was used to study the flow in the wake and the grooves of a cactus shaped cylinder model. Experiments were done in an open loop L-shaped wind tunnel at flows of high Reynolds numbers of 50x10³ to 200x10³ which mimics the strong wind storms. Detailed mean and instantaneous flow analysis were done. Moreover, vorticity analysis was done on the shear layer of the grooves and the immediate wake of the cactus in order to understand the vortex shedding and their interactions. Our results showed an improved aerodynamic behavior for the cactus as its wake showed lower stream wise turbulent intensity than its counterpart circular cylinder. Furthermore, the role of the grooves was identified in improving the vortex shedding. The spikes of the cactus act as a vortex generator that help in reducing the shear and friction forces and lubricate the flow around the cactus cylinder.