Improved delayed detached-eddy simulation of massive separation around triple cylinders

摘要

The massively separated flow past triple cylinders(Tri C) in tandem arrangement is simulated using the improved delayed detached-eddy simulation(IDDES)method based on the shear stress transport(SST) model, coupled with the high order adaptive dissipation scheme. The spacing between adjacent cylinders is sub-critical(1.435D).IDDES prediction of two cylinders(TC) with the same spacing is compared to experimental data for validation, and the numerical results agree well with the available measurements, except for the asymmetry in the gap region. The flow past Tri C is investigated using the same method. Generally,the mean flow quantities past Tri C, such as the velocity,pressure, and vorticity, are similar to the corresponding components of TC. However, the pressure fluctuations on the Tri C surface are uniformly larger than those on TC. Meanwhile,the instantaneous flows past Tri C are much more complex.The periodical blockage in the first gap region is found in the Tri C case and leads to the up-and-down movement of shear layer in the second gap region.