CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CFX (http://www.cfd-online.com/Forums/cfx/)
-   -   upwind vs high resolution (http://www.cfd-online.com/Forums/cfx/22075-upwind-vs-high-resolution.html)

Richard January 23, 2006 05:31

upwind vs high resolution
 
I am running a simulation on a pump. While using the upwind model, i get a pressure diffenences of 3000pa between inlet and outlet. When i switch to high resolution, i only get 1000pa of differences. What causes the big differences. In fact i was hoping for a pressure differences of more than 3000 pa, not less while switching to the high resolution setting. Pls help. Any advices is welcome.

TB January 24, 2006 22:42

Re: upwind vs high resolution
 
Many factors will affect your solution. However, upwind scheme is not accurate. Often it will end up with faulty solution. I normally use upwind to get some quick solution that can be used as an initial condition in high order scheme.

Alex February 16, 2006 13:05

Re: upwind vs high resolution
 
hi, how do you posttreat your job? do you use the massflowave? You have to use results of upwind scheme to obtain more quikly a solution with high resolution advection scheme. The upwind adv scheme consist in putting beta value at 0 (second order effect are neglect). Are you french? If yes, it could be easier to speak french when you are going to gie me an answer.

BADRINATH February 20, 2006 07:35

Re: upwind vs high resolution
 
Hi, The major difference between upwind scheme and the high resolution scheme is that: When we are not usre about the boundary conditions which we got from the test results and accuracy is not a criteria and need of fast convergence we normally use upwind scheme, where as the high resolution scheme we use that when we are confident about the boundary conditions and accuracy is a constraint which we need we ll use the high resolution scheme.

Comming to the post treat use the massflowave to prost process the variable so that you ll not find much variation when compared to areaave.

Regards Badrinath


All times are GMT -4. The time now is 20:31.