# Solution converged, and then diverge again.

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 September 11, 2007, 07:01 Solution converged, and then diverge again. #1 jrg Guest   Posts: n/a Hi. I am simulating a rectangular duct flow with 90 degrees inlet and outlet. Flow is laminar and I use the pressure solver, simpleC, standard pressure and 2nd order upwind momentum discretization. To assess convergence, I monitor the average velocity at the outlet. After a few hundred iterations (say 300), the value becomes very constant and one would think the solution has converged. But if I keep iterating, oscillations appear and I would need to iterate another few hundred before it becomes constant again. I did in total a few thousand iterations and I could see this cycle repeating. Does this imply that the solution at 300 iterations is not the converged solution? Is there any possibility that a converged solution would diverge with more iterations? Thanks. mohitmmb likes this.

 September 11, 2007, 15:37 Re: Solution converged, and then diverge again. #2 AAA Guest   Posts: n/a try adapting velocity gradient

 April 1, 2013, 23:10 #3 New Member   Mohit Join Date: Mar 2013 Posts: 7 Rep Power: 6 hi .... if u solve this problem then pls send me copy of solution of this.... i am also doing same and facing problem ... my e mail id is mohitmmb@gmail.com ;145276]Hi. I am simulating a rectangular duct flow with 90 degrees inlet and outlet. Flow is laminar and I use the pressure solver, simpleC, standard pressure and 2nd order upwind momentum discretization. To assess convergence, I monitor the average velocity at the outlet. After a few hundred iterations (say 300), the value becomes very constant and one would think the solution has converged. But if I keep iterating, oscillations appear and I would need to iterate another few hundred before it becomes constant again. I did in total a few thousand iterations and I could see this cycle repeating. Does this imply that the solution at 300 iterations is not the converged solution? Is there any possibility that a converged solution would diverge with more iterations? Thanks.[/QUOTE]

 November 15, 2017, 09:27 Solution Manual of numerical heat transfer and fluid flow from Patankar #4 New Member   yadollah Join Date: Nov 2017 Posts: 3 Rep Power: 2 If somebody do have the Solution Manual of numerical heat transfer and fluid flow from Patankar, send me a copy by email cheshkhavar@gmail.com. I really need it. I would be grateful for your favor.

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