Validation issue in CFD

fruitkiwi · April 24, 2012, 03:03

Hi, Dear all,

I met a deadlock in CFD modelling and wish to listen your advice.
I try to simulate flow past through a cylinder.I manage to let it work.
However, today i am questioned when i present it.

1. How are you going to validate your simulation? different article has their own method to simulate the result, which is a cause and effect. You use different boundary condition from them,it should lead different result.

I am wondering, why i cannot only compare results part and i need to go through a CFD paper from beginning to the end?

I am newbie, critics is allowed in this thread. please.

cfdnewbie · April 24, 2012, 03:40

In case your code has been validated (the equations are discretized properly, it converges to the exact solution if you increase the resolution), then there's not much you can do. Check if the physics of the example are set up correctly (things like freestream conditions and such), do grid convergence to get some faith in your results.#

If you are doing the flow over a cylinder, that should be easy to compare with other published results. Check the Strouhal number, if that's close to whats published (Strouhal number is pretty easy to get right), work on to things like lift and drag curves....

hope this helps!

FMDenaro · April 24, 2012, 03:46

as previously said, if your code is already validated then you can do your computation ... try to check grid-independence ..

fruitkiwi · April 24, 2012, 04:20

Hi, cfdnewbie,

Thank you for your advices.
Then i can let it go and jump into the biofluid field.
Any advice you want to give me before i throw myself into bio fluid dynamics CFD modelling?I heard it sounds terrible.My supervisor said "read as much as you can and validate it, use your cylinder which is similar to blood vessel."

Hi, FMDenaro
thanks.

April 24, 2012, 03:03	Validation issue in CFD	#1
fruitkiwi Member kiwi Join Date: Mar 2012 Location: South East Asia Posts: 58 Rep Power: 14	Hi, Dear all, I met a deadlock in CFD modelling and wish to listen your advice. I try to simulate flow past through a cylinder.I manage to let it work. However, today i am questioned when i present it. 1. How are you going to validate your simulation? different article has their own method to simulate the result, which is a cause and effect. You use different boundary condition from them,it should lead different result. I am wondering, why i cannot only compare results part and i need to go through a CFD paper from beginning to the end? I am newbie, critics is allowed in this thread. please.

April 24, 2012, 03:40		#2
cfdnewbie Senior Member cfdnewbie Join Date: Mar 2010 Posts: 557 Rep Power: 20	In case your code has been validated (the equations are discretized properly, it converges to the exact solution if you increase the resolution), then there's not much you can do. Check if the physics of the example are set up correctly (things like freestream conditions and such), do grid convergence to get some faith in your results.# If you are doing the flow over a cylinder, that should be easy to compare with other published results. Check the Strouhal number, if that's close to whats published (Strouhal number is pretty easy to get right), work on to things like lift and drag curves.... hope this helps! fruitkiwi likes this.

April 24, 2012, 03:46		#3
FMDenaro Senior Member Filippo Maria Denaro Join Date: Jul 2010 Posts: 6,768 Rep Power: 71	as previously said, if your code is already validated then you can do your computation ... try to check grid-independence .. fruitkiwi likes this.

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April 24, 2012, 04:20		#4
fruitkiwi Member kiwi Join Date: Mar 2012 Location: South East Asia Posts: 58 Rep Power: 14	Hi, cfdnewbie, Thank you for your advices. Then i can let it go and jump into the biofluid field. Any advice you want to give me before i throw myself into bio fluid dynamics CFD modelling?I heard it sounds terrible.My supervisor said "read as much as you can and validate it, use your cylinder which is similar to blood vessel." Hi, FMDenaro thanks.