

Hello,
I have been trying to validate flow over a heated square cylinder using buoyantBoussinesqPimpleFoam. However, the lift coefficient is seen to be positive instead of negative values. Also, the wake is not captured properly. I am using OpenFOAM 5 as the newer versions consider Boussinesq approximation as an equation of state which am afraid is not a proper way.
Please see below the link to my case file and share your suggestions if you have had any similar experiences.
Thank you
Damu
OpenFOAM


Hi,
Can you attach the paper you are trying to validate?
Regards,
Divyesh Variya


Hi Divyesh,
Thanks for the response. Please see below the url for literature.
Hi,
Can you cross-check values of velocity, viscosity & Temperature difference?
To use the Boussinesq approximation method, there is a constraint of Temperature difference. In your case, it is 31.5 Which is very large. It seems due to these reasons you are not getting the correct results.
Thanks,
Divyesh Variya
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the case file has velocity value 1 m/s
Temperature difference is 31.5. I think you need to correct and run again.
Hi Divyesh,
This output belongs to the new case with parameters as mentioned in my previous comment.
Gr=10^4, Re=200(as per the literature previously attached)
Temperature diff.(assumed)=1. Square cylinder side is of 1 unit. beta=3.33e-03. V=0.36. nu=1.8e-03. All dimensions as per SI
Looks like velocity-viscosity values are not working. Could you try some other combinations by changing temp. diff. or you could get more specific values if you dig some more literature. There are a couple of people who did the same simulations for validation. You could look at their papers.
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The characteristic length will be the height of the cylinder and based on the above values grashoff number will give you a temperature difference.
I hope you are using the same domain inlet length. And calculating velocity based on that length with given Reynolds no.
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Please include the attachments so we can better assist. roofing companies lorain Thanks a lot.
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