Detached eddy simulation for turbulent flows in a pipe with a snowflake fractal orifice

Abstract

Turbulent flows in a pipe with a snowflake fractal shape (SF2) orifice are investigated using the parallelized, density-based, dynamic mesh and detached eddy simulation code (DG-DES) (Xia, PhD thesis, 2005; Xia and Qin, AIAA 2005- 106, 2005). For comparison with the laboratory experiment, the flow is essentially a low Mach number flow. In order to tackle the low speed problem of the density based method, the SLAU (Simple Low dissipation AUSM) (Shima and Kitamura in 47th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, AIAA 2009-136, 2009) is adopted in this paper. The schemeexhibits low numerical dissipations for low speeds and needs no problem-dependent “cut-off Mach number”. The results for the flows after the orifice are compared with those of the corresponding experiment (Chong, PhD thesis, 2008). Comparisons show good agreements in the mean velocity profiles at the different holes.