timestep for viscous compressible flows
Can anyone suggest a good timestep formula for explicit compressible viscous flow on unstructured grids. On quadrilateral (2D problem), if i stretch cells at wall boundaries solution is diverging after some number of iterations even if i use small cfl number. problem is converging for triangular grids as amount of stretching is less compared to quadrilateral grid.
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Re: timestep for viscous compressible flows
dt < rho*Pr*L^2/(4*gamma*visc)
where L is a charateristic dimension of the cell check Turkel et al.(1991), NASA TR. |
Re: timestep for viscous compressible flows
Thank you for your response.
Earlier for inviscid computation i am using fallowing timestep. dt = sqrt(area of cell)/(sqrt(u^2+v^2)+ c). u and v are two velocity components, c is wave speed. the time step which you have suggested is alone sufficient for viscous computation or i need to combine both inviscid, viscous time steps? how can i get the paper which you have suggested. Thank you. |
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