Large eddy simulation of flow past a square cylinder with rounded leading corners: A comparison of 2D and 3D approaches.

The unsteady flow past a square cylinder with rounded leading corners is predicted at Re = 2600 by large eddy simulations (LES). The corner radius r is fixed at 3 mm and the cylinder width D is 12.7 mm, resulting in r /D = 0.236. Detailed comparisons are made between the two-dimensional (2D) and the three-dimensional (3D) results with previous experimental measurements [32, 33]. The results show that the Strouhal number agrees well with previous measurement [33], indicating that both 2D and 3D LES are capable of capturing the shedding of large-scale vortical strutures. The statistical quantities (e.g., the drag and lift coefficients, the time-averaged streamwise velocity, the root-mean-square of streamwise velocity and the Reynolds stress) were calculated and validated against experimental results [32, 33]. The 3D LES results show reasonable agreement with the experimental measurement [32, 33], while the results predicted by 2D LES deviate far from the experimental measurement [32, 33]. It is further demonstrated that the recirculation length and the vortex formation length are consistent with experimental results [33], while it is greatly shortened in 2D LES. [ABSTRACT FROM AUTHOR]