Not getting Convergence using explicit solver.

- December 11, 2020 at 3:14 am
  
  Prem1996
  Subscriber
- December 11, 2020 at 4:05 am
  
  Prem1996
  Subscriber
  
  One more thing, max skewness for my mesh is 0.95455 and average (skewness) is 1.7671e-002. Min orthogonal quality is 0.12922 and average (orthogonal quality) is 0.99292.n Last Picture shows the cells with maximum skewness.n
- December 11, 2020 at 4:55 pm
  
  Rahul Kumar
  Ansys Employee
  
  Hello,nTo calculate the CFL, please refer to the Theory guide (Eqn. 28.86) : https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v202/en/flu_th/flu_th_sec_ss_flow.htmlnTry with standard initialization and you could also try with courant number of 1. nTo start off with, you could use first order upwind and then switch to second order. n
- December 14, 2020 at 12:10 pm
  
  Rob
  Forum Moderator
  
  Also check the mesh, that looks like the sort of cell quality plot I'd expect from an old style O-grid. n
- December 17, 2020 at 10:22 pm
  
  Prem1996
  Subscriber
  
  Thank You Sir!!n
- January 1, 2021 at 11:05 pm
  
  Prem1996
  Subscriber
  
  Sir, I had tried with different courant Number starting from 1 with the first order and second order upwind but in both the case the y and z velocity is not converging. I attaching the graph below. This is generated with second order upwind and courant 1 and if I use first order upwind then those oscillation are minimized and gives a smooth graph but still the y and z velocity not converging with explicit spatial and transient formulation and even residuals did not go below 10^ (-1). nCan anyone tell me where I had done a mistake or what I have to do for convergence??n