Dear Baofeng, I think the session files looks OK. How long have you run for. I note you have a very symmetric mesh and so in 2D it can take quite a while (O(100)) for the flow to break symmetry and then shed. I am not sure if this will be the case in a Hex mesh such as yours. Also the properties of shedding near a wall can be quite different to a cylinder away from a wall. Although I would have expected Re=500 to be sufficient for it to shed. So you could think of adding an asymmetric blowing onto one of the lateral walls and if you run that for a 1000 time steps and then turn it off it might kick start the shedding. Cheers, Spencer. [cid:F38B9E49-2732-40FC-ADA9-B372CF995775@vlan147.poli.usp.br] On 15 Aug 2017, at 08:28, BF MA <bf-ma@buaa.edu.cn<mailto:bf-ma@buaa.edu.cn>> wrote: Hi everyone, I am simulating the vortex flow around a squared cylinder mounted a surface using Nektar++ incompressible solver. For this layout (see attached 1), the vortex wakes will become unstable and be shedding as Re >150. However, the current problem is that the computation cannot get the unsteady vortex shedding, it always converges to steady solutions even at Re=500. I even tried giving an incoming disturbance, but the flow fields still cannot converge to vortex shedding. The steady drag coefficients at various Re agree well with the time-averaged results in previous publications, but no vortex shedding occurs. I have simulated the vortex flow past a 2D cylinder, and vortex shedding can be obtained. But for the 3D case, the results are strange. I attached the layout and grid file, and anyone can give some suggestions. Many thanks, Baofeng Baofeng Ma, PH.D Associate Professor Institute of Fluid Mechanics School of Aeronautical Science and Engineering Beihang University Email: bf-ma@buaa.edu.cn<mailto:bf-ma@buaa.edu.cn> Tel: 0086 (0)10 82338344 <layout.jpg><cuboid_4w.xml> Spencer Sherwin McLaren Racing/Royal Academy of Engineering Research Chair, Professor of Computational Fluid Mechanics, Department of Aeronautics, Imperial College London South Kensington Campus London SW7 2AZ s.sherwin@imperial.ac.uk<mailto:s.sherwin@imperial.ac.uk> +44 (0) 20 759 45052
