velocity is going beyond its initial value

Ank · June 8, 2013, 06:56

Hey

This thread is related to the thread http://www.cfd-online.com/Forums/ope...r-channel.html

Initially I was using the buoyantBoussinesqSimpleFoam solver to simulate air flow inside a heated rectangular channel or pipe. The velocity was 1 m/s at the inlet but it increased to 1.1 m/s as it approached the outlet.

After that I have modified the simpleFoam solver and added T equation in it (Based on the guidelines given at http://openfoamwiki.net/index.php/Ho...ure_to_icoFoam)

I am not so sure whether I have done it rightly or not, but it is running good. The problem is that the results are similar to buyoant solvers and not good.

I m not able to understand the reason.

Any suggestion?

nimasam · June 8, 2013, 08:40

Dear ankur
whats wrong with velocity result? it may differ from initial condition and its not wrong at all

, you may give a uniform velocity at inlet, but when it reaches outlet, velocity profile will be changed, it reduces near wall for no slip condition and get sharper at the middle plane

and have a value more than 1 m/s, i think you should provide some plots here to show us what is wrong?

Ank · June 8, 2013, 09:07

Hey nima sam

Thanks alot for your reply..

I think I got your point. It was silly from my side. I did not check the results (without temperature case) properly. I did it again and waited for more time. It is giving the same result as with the temperature.

but the positive point is I understood how it happens now, and learned how to modify the solver

Thanks alot..I think to have a mass balance velocity peaks at a certain point.

June 8, 2013, 06:56	velocity is going beyond its initial value	#1
Ank Member ankur Join Date: May 2012 Location: India Posts: 50 Rep Power: 13	Hey This thread is related to the thread http://www.cfd-online.com/Forums/ope...r-channel.html Initially I was using the buoyantBoussinesqSimpleFoam solver to simulate air flow inside a heated rectangular channel or pipe. The velocity was 1 m/s at the inlet but it increased to 1.1 m/s as it approached the outlet. After that I have modified the simpleFoam solver and added T equation in it (Based on the guidelines given at http://openfoamwiki.net/index.php/Ho...ure_to_icoFoam) I am not so sure whether I have done it rightly or not, but it is running good. The problem is that the results are similar to buyoant solvers and not good. I m not able to understand the reason. Any suggestion?

June 8, 2013, 08:40		#2
nimasam Senior Member Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,266 Blog Entries: 1 Rep Power: 24	Dear ankur whats wrong with velocity result? it may differ from initial condition and its not wrong at all , you may give a uniform velocity at inlet, but when it reaches outlet, velocity profile will be changed, it reduces near wall for no slip condition and get sharper at the middle plane and have a value more than 1 m/s, i think you should provide some plots here to show us what is wrong? __________________ My Personal Website (http://nimasamkhaniani.ir/) Telegram channel (https://t.me/cfd_foam)

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June 8, 2013, 09:07		#3
Ank Member ankur Join Date: May 2012 Location: India Posts: 50 Rep Power: 13	Hey nima sam Thanks alot for your reply.. I think I got your point. It was silly from my side. I did not check the results (without temperature case) properly. I did it again and waited for more time. It is giving the same result as with the temperature. but the positive point is I understood how it happens now, and learned how to modify the solver Thanks alot..I think to have a mass balance velocity peaks at a certain point.