Characterization of the Turbulent Flow Around Complex Geometries Using Wall-Modeled Large Eddy Simulation and Immersed Boundary Method

Abstract

This study investigates the applicability of the Large Eddy Simulation method with a simple near-wall model to simulate flow separation due to complex immersed geometries. A numerical model was, therefore, developed to solve the governing equations on a staggered Cartesian grid system, in which the flow obstacles are modeled using the immersed boundary method. The near-wall region is approximated using simplified boundary layer equations, aiming at achieving reliable results with a low computational cost. In this study, the accuracy of the numerical model was first evaluated by considering a three-dimensional turbulent flow past an infinite-length circular pile. The corresponding numerical results, particularly the main flow features in the wake region, were found to be in good agreement with experimental and numerical results obtained from reference studies. The numerical model was then applied to simulate the flow around a pile-supported pier, a vital structure in the river and coastal environment, presenting results beyond the former background knowledge available for this case. The available experimental results for the pier case show the good accuracy of the present numerical results. Moreover, the numerical model enabled to characterize the most relevant flow features due to the pier demonstrated the efficiency of the numerical methods employed to study the flow structure formed around complex geometries.