Fluids

Fluids

Mesh quality for Transition SST turbulence method

    • Luca_Patriarchi
      Subscriber

      Good evening,

      I am studing a 2D supercritical airfoil at low Reynolds number and turbulent intensity of 0.02%. For the analysis I am using a Transition SST as turbulence model, whitch requires a good quality mesh for. I generated a mesh with mesh metrics paramenters of orthogonality close to 1 and maximum value of skewness less than 0.33; also, the length of the first cell is near 1.81e-05 with a grouth rate of 1.2 in order to well capture the velocities gradients in the boundary layer. The problem is that I do not obtain convergence, but it diverges. I suppose that the main issue is that the mesh I generated presents many transitions in the cells' length that could produce to large gradients of the main quantities, leading to divergence of the method. I would like to know what do you think about the mesh and, in case, any suggestions to improve the overall quality of the mesh.

      In attachment, screenshots of used parameters, mesh and mesh metric parameters.

      Thanks in advance.

      Luca Patriarchi

    • Keyur Kanade
      Ansys Employee
      If you are concerned about mesh, here are my 2 cents. The min orthogonal qulity of 0.1 is good to proceed in Fluent. Please check the density of the mesh at various places in you case. Please make sure that there is not sudden jump from fine to coarse mesh. Regards, Keyur How to access Ansys Online Help Document Guidelines on the Student Community
    • Rob
      Ansys Employee

      As Keyur comments, the skew is good, but the streamwise cell growth rate may be less good. Also, if you're expecting flow separation you need a much lower aspect ratio: stretched cells are fine for aligned flow, not so much when it's not. 

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