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 Tadiwos October 9, 2001 07:34

create over flow

I have simulated a bicycle helmet and want to create an over flow . The experimental set up uses a ventillater on a man riding a stationary bike. I want to simulate the heat transfer. My problem is how can I create inlet for the flow. Do you think it is advisable to model a big room and inlet somewhere in the room? Currentely I have only the helmet model.

Thanks for your help

TZ

 Herve October 9, 2001 11:18

Re: create over flow

If you want to look at the flow around the helmet and the heat transfer from the outside-in, then you need to model a domain around the helmet. So having a large box around it is a way to do it. What you want to ensure is that the flow can develop prior to reaching the helmet, and that any recirculation and turbulence effect has dissipated. So I think that one length scale btw the helmet and the inlet and 3 maybe behind it is advisable. This is how one would do for a car or a plane simulation.

 Tadiwos October 10, 2001 03:55

Re: create over flow

Thanks Herve for your advice, but do you think it is avisable if I make the face of the box infront of the helmet back side of the helmet as open space i.e. by labelling the two opposite faces inlet and outlet?

thanks

 Herve October 10, 2001 04:35

Re: create over flow

I think you could (you could also use inlet and opening in CFX-5), but you want to make sure that the situation you model is as close as possible from your wind tunnel set up (e.g. is your helmet mounted on a kind of "human head"?). So watch out for the other boundary conditions and the other solids in the domain. If your helmet is symmetrical use a symmetry plane.

 Tadiwos October 10, 2001 04:51

Re: create over flow

Thanks Herve, I will try to implement it.

TZ

 Electrico May 3, 2010 12:30

hello, I'm simulating the airflow over a bicycle helmet and i'm using different geometries for the simulations. Can you send me your helmet model? I'ill be waiting for your answer.
thank you

Quote:
 Originally Posted by Tadiwos ;62788 I have simulated a bicycle helmet and want to create an over flow . The experimental set up uses a ventillater on a man riding a stationary bike. I want to simulate the heat transfer. My problem is how can I create inlet for the flow. Do you think it is advisable to model a big room and inlet somewhere in the room? Currentely I have only the helmet model. Thanks for your help TZ

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