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-   -   must improve skewness ? (http://www.cfd-online.com/Forums/fluent/43548-must-improve-skewness.html)

mario January 30, 2007 20:51

must improve skewness ?
 
Hi, I have been doing a excercise on dynamic mesh, with Remesh option, I also switch on 'must improve skewness', but when I preview the mesh motion, nothing is acturally improved, the mesh is simply skewed seriously till negative mesh occured. pls help! thanks! mario

pinks January 31, 2007 00:08

Re: must improve skewness ?
 
Must improve skewness option says, that remesh only if skewness is improved. Anyways there are lot of parameters what decides the remeshing. If you could explain the geometrical setup and the motion, I would be in abetter condition to comment. 1.For the time being, try with lower time step.time step should be less than (gridsize/typical velocity of moving zone). 2.if you have 3D geometry, try with face remeshing, 3.Add smoothing as well. 4.try size remesh interval ->1 in dynamic mesh parameters, remeshing panel.


mario January 31, 2007 02:01

Re: must improve skewness ?
 
my geometry is just a 2D rectangular box. the left side is set as pressure inlet, the right side is set as pressure outlet. the upper and lower side is set as wall (stationary). and there is another small rectangular box move inside this big box. I set the small box and its neigbor area move as rigid body (controled by a profile), but the inlet/outlet/wall are all set to be stationary. when I do the mesh motion preview, the mesh cells beside the outlet are compressed and obviously became skew, but they never be remeshed or collapsed like with layering option. I check the UG, it says, cells with high skewness value will be marked and remeshed, but in my case, it seems nothing happen to those highly skewed cells. so, very confusing...

I add smoothing with default parameters, and change the interval to 5, 10, but the problem remains.


pinks January 31, 2007 07:46

Re: must improve skewness ?
 
Hi, If you have a box inside a box, you can have quad mesh in it. Then y dont u try with layering? Y r u looking for remeshing? If you could send me your case file at the following ID i will surely solve your problem. Please clarify when you can have quad mesh y r u looking for remshing? pinkscfd@gmail.com


mario January 31, 2007 09:10

Re: must improve skewness ?
 
thanks, pinks, i have tried quad mesh with layering, and succeed to do so. right now, i want to study remesh, so just try it with tet mesh. I will send my case to you, thanks again.


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