An immersed boundary finite difference method for LES of flow around bluff shapes

Abstract

SUMMARYA three-dimensional numerical model using large eddy simulation (LES) technique and incorporating the immersed boundary (IMB) concept has been developed to compute ow around blu shapes. A fractional step ÿnite di erences method with rectilinear non-uniform collocated grid is employed to solve the governing equations. Blu shapes are treated in the IMB method by introducing artiÿcial force terms into the momentum equations. Second-order accurate interpolation schemes for all sorts of grid points adjacent to the immersed boundary have been developed to determine the velocities and pressure at these points. To enforce continuity, the methods of imposition of pressure boundary condition and addition of mass source=sink terms are tested. It has been found that imposing suitable pressure boundary condition (zero normal gradient) can e ectively reproduce the correct pressure distribution and enforce mass conservation around a blu shape. The present model has been veriÿed and applied to simulate ow around blu shapes: (1) a square cylinder and (2) the Tsing Ma suspension bridge deck section model. Complex ow phenomena such as ow separation and vortex shedding are reproduced and the drag coe cient, lift coe cient, and pressure coe cient are calculated and analyzed. Good agreement between the numerical results and the experimental data are obtained. The model is proven to be an e cient tool for ow simulation around blu bodies in time varying ows.

A differentially interpolated direct forcing immersed boundary method for predicting incompressible Navier–Stokes equations in time-varying complex geometries

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An immersed boundary method for the incompressible Navier–Stokes equations in complex geometry

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Enhancement of Heat Transfer of Mixing Convection in a Vertical Channel by a Moving Block

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