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-   -   Laminar flow (http://www.cfd-online.com/Forums/fluent/43567-laminar-flow.html)

mech January 31, 2007 21:41

Laminar flow
 
Dear all

Have you had any problems with laminar flow?

My numerical modeling deal with lamiar flow. I just though that numerical modeling for laminar flow would be simple.

But, numerical data does not match with experimental data. I do not say the data value.

The trend is different.

For example, imagine that temperature of number 1 sample is higer than number 2 sample. But, numerical results are opposite

I have tried to match numerical data with experimental data. ( increase mesh number, change mesh , 3d dp, SIMPLE/SIMPLEC/PISO, second order momentum/pressure/energy, etc )

I couldn't.

Actually, for laminiar flow, there are very few setting to change comparing to turbulent flow.

Do you have any ideas?

Thanks


wabik February 1, 2007 04:10

Re: Laminar flow
 
Hi,

I have a similar problem with laminar flow. In my case oscilations of temperature are much higher then experimantal data and similar to your case there is not much to change in the model :(

Brgds, wabik

kk February 1, 2007 13:45

Re: Laminar flow
 
I think near wall treatment is the critical part in laminar flow modeling. I am going to do the experiment and the laminar flow too. Hope my intensive grid near the walls can help. Crossing fingers. :)

mech February 1, 2007 15:10

Re: Laminar flow
 
Hi. Wabik

I have also a same problem.( oscilations of temperature )

In my case, as I increase mesh number, I check the temperature. When I used small number of mesh, there was no oscilations of temperature. But, at the large number of mesh, there was oscilations of temperature.

I think that oscilations of temperature maybe depends on mesh number or mesh quality.( Of cousre, not always )

To match numerical data and experimental data, I try to change discretization scheme. As you can see, there are very few things to change for laminar flow.

Do you have any experience to change discretization scheme as you are doing a numerical modeling?


mech February 1, 2007 15:18

Re: Laminar flow
 
Hi. kk

I hope your research go well.

In my case, I also increased mesh numbers near wall. But, there was not a significant difference. I checked up to 2,600,000 mesh.. -_-

So, I try to change discretization scheme so that I match numerical data with experimental data, . As you can see, there are very few things to change for laminar flow.

Do you have any experience to change discretization scheme as you are doing a numerical modeling?

Good luck!!



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