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Velocity, Pressure or Mass flow inlet condition

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Old   January 6, 2017, 05:36
Question Velocity, Pressure or Mass flow inlet condition
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Martijn
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Hi everyone,

I've been looking in to the theory behind CFD simulations and hit an obstacle trying to figure out inlet boundary conditions.

My Question: Do pressure and mass-flow inlet condition assume a velocity profile or is the real profile determined by the simulation

My hypothesis: Pressure inlet condition do not assume a velocity profile, mass-flow inlets do assume a uniform velocity profile to begin with, but only as a initial condition.

I don't really care if my hypothesis is right, I just really want to know what the theory behind it is. I've tried looking in the Ansys Theory Guide, Ansys User Guide and two handbooks I've had lying around, but couldn't find a satisfying answer.

If any of you could shine some light on this subject, and preferably direct me to some kind of background information on boundary conditions that would be great.

Note this is just for information, the question isn't related to any specific project or software. If any more information is required just ask.

Thanks!
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Old   January 6, 2017, 05:44
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Filippo Maria Denaro
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If you consider compressible flows, have a look to this article
https://www.researchgate.net/publica..._viscous_flows

it is quite old but still good for your task and you can find useful the references.

If you are interested in incompressible flows, you can start from this hystorical paper http://link.springer.com/article/10.1007/BF01061454

and then searching for more recent studies. Specifically, as the pressure is not a thermodinamic function, you should search for the Hodge decomposition in incompressible model.
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Old   January 6, 2017, 10:43
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Martijn
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Hi,

Thanks for the quick response. The question mainly focuses on incompressible flow. I've started reading the document you've suggested but i'm somewhat in over my head it seems. It looks like I have to brush up on my math skills before starting this path.

Nevertheless thanks for the starting point and if I run into any other trouble I'll be sure to post here again.

Have a great weekend,
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Old   January 6, 2017, 11:06
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Filippo Maria Denaro
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Quote:
Originally Posted by brwmkprules View Post
Hi,

Thanks for the quick response. The question mainly focuses on incompressible flow. I've started reading the document you've suggested but i'm somewhat in over my head it seems. It looks like I have to brush up on my math skills before starting this path.

Nevertheless thanks for the starting point and if I run into any other trouble I'll be sure to post here again.

Have a great weekend,
You could also find
https://www.researchgate.net/publica...conditionssome details and the literature about BC.s for incompressible flow in my paper
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