FLoWorks help

[element94]

I need some help with COSMOS FLoWorks. I'm doing external flow analysis with questionable results. FLoWorks is showing a drag force of 2 lbs on an object I know has around 70 lbs. When I show flow trajectories they flow thru the body and not around. It's like the body does not exist. It's not the component control because all bodies are enabled. Help please. Thanks.

 

[SolidMatt]

Try to use the Floworks "check geometry" tool. (FloWorks > Tools > Check Geometry, Check) It will tell you the volume of what it recognizes as fluid and solid. If it reports that you have 0 solid volume then you may have a problem. This tool should really be used on every model, especially in assemblies the "check for invalid contact" option can be a lifesavor when troubleshooting.

Hope this helps.. -Matt

 

[NickE]

also if the body is sheet metal or similar and the thickness is thinner than the gridding then the body may not exist.

 

[element94]

What will say if there is an invalid contact? It's showing me a fluid volume of 913 ft^3 and a solid volume of .084 ft^3.

 

[element94]

How can I get the body to exist of it's thin?

 

[SolidMatt]

If there is invalid contact it will tell you in that window which features on which components are interfering.

If you have a thin model, you may need to refine your mesh. Go to your local initial mesh settings. There are 4 tabs, click the help button on each to learn what each option will do for you. If you still can't get it to work with these settings you may need to look into "control planes" in the help menu.

-Matt

 

[hiyer]

when you plot the mesh on a 2D plane do you see this component resolved properly?? if the component is not resolved then the flow would go right through it. if the component is thin as compared to other components then you might have to specify the min. wall thickness or use control planes for meshing.

 

[element94]

Ok, I will try your recommendations. Thanks, I'll be back tomorrow!

 

[element94]

Ok, when I plotted on a 2D plane the flow went through it. I changed the minimum wall thickness to .6 in (it was set at 1.147 ft!!)and that made the difference. I get awesome results, One problem, the time to compute the results is horrible. I set the gap resolution to the minumum and I stopped it after 13 iterations and it still took over an hour. Any idea how to speed it up? Thanks!