A ghost-cell immersed boundary method for large eddy simulation of flows in complex geometries

Abstract

An efficient ghost-cell immersed boundary (IB) method is proposed for large eddy simulations of three-dimensional incompressible flow in complex geometries. In the framework of finite volume method, the Navier–Stokes equations are integrated using an explicit time advancement scheme on a collocated mesh. Since the IB method is known to generate an unphysical velocity field inside the IB that violates the mass conservation of the cells near the IB, a new IB treatment is devised to eliminate the unphysical velocity generated near the IB and to improve the pressure distribution on the body surface. To validate the proposed method, both laminar and turbulent flow cases are presented. In particular, large eddy simulations were performed to simulate the turbulent flows over a circular cylinder and a sphere at subcritical Reynolds numbers. The computed results show good agreements with the published numerical and experimental data.

Keywords:

• immersed boundary method
• large eddy simulation
• finite volume method
• ghost cell
• mass conservation

Acknowledgements

The authors are grateful to the Tsinghua National Laboratory for Information Science and Technology for the support of parallel computation.

Additional information

Funding

The work was supported by National Natural Science Foundation of China under Grants [number 11322221], [number 11132005], [number 11490551]; Tsinghua University Initiative Scientific Research Program under Grant [number 20131089267].