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lingdeer September 27, 2011 15:41

Reference presssure for blood flow FSI

I want to seek some expertise on experience with ANSYS CFX.
I am doing blood vessel FSI and set reference pressure as 1atm in the fluid domain. I did't include pref in force calculation.

When I look at the CFD output file, it said pref is not included in pressure force calculation. That makes me think what is the importance of setting the reference pressure . And I found it's mostly important for gas problem.

If I use 1atm (=760mmHg) as reference pressure, will it affect my FSI simulation result for imcompressible fluid, as the pressure change is ~< 1mmHg?

Also, does it mean that the pressure outside my vessel wall is also 1atm?
I am thinking about running another test to check that, but it takes a week to turn another set. I wonder if someone can just tell me from their experience, because I am using this converged steady results as initial condition for transient FSI, so I want to know I am using correct results for my consecutive simulations.

And for the next time I should set it as 0Pa, is that right? Or is it not so important for liquid flow?

Thank you in advance! :)

stumpy September 27, 2011 16:33

For incompressible flows it really doesn't matter what you use as the reference pressure (unless you include it in the forces!), but I would still use 1 atm since that is the correct physical pressure. Just make sure your inlet/outlet pressures are then set as relative pressures and not absolute pressures.

lingdeer September 27, 2011 16:54

Great! I totally solved my doubts! Thank you so much!!! :)

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