Parametric investigation of spatio-temporal variability of submerged body hydrodynamics

Abstract

The spatio-temporal dynamics of the flow around a wall-mounted bluff body immersed in a turbulent boundary layer is investigated numerically, on a 2D vertical plane using ANSYS-Fluent, over a wide parameter ranges. The submergence ratios (SR) considered for the study are 1.5–10, that covers the entire regime of low, intermediate, and high SR. The Reynolds numbers (Reh) considered are 8,400−56,000, that falls within the turbulent regime. The steady and fluctuating flow fields are investigated as a response to varying SR and Reh. It is demonstrated that in the Reynolds numbers range considered, there exists an optimum SR up to which normalized mean reattachment length is proportionate to SR and beyond that optimum value, normalized mean reattachment length is inversely proportionate to SR. In general, the maximum reattachment length over the entire SR range considered, does not show any coherent variability with Reh. Maxima and minima of the normalized mean velocity fields are found to be inveresly proportionate to SR (with varying degree) and independent of Reh. The skin friction coefficient, Cf is proportional to Reh and inversely proportional to SR on all three edges of the obstacle. The maximum Reynolds shear stress seems to occur approximately at the reattachment point. The general observation is: the time-averaged kinematic fields are asymmetrically more influenced by SR over Reh, whereas time dependent fluctuating fields show much higher dependence on Reh compared to SR.