Learning Forum

[Valenjin]

Hello!nIm very new to ansys and i was wondering if in order to simulate bloodflow in a artery i can simplay say the inlet speed is 0,91 m/s (thats the average speed at the heart) and then for the pressure i create a function with high value of 0,159 bar and a low value of 0,106 bar.nnAnd that way have the flow through the artery depending on the heartbeat. Does that sound logical? I wasnt sure how else to approach it yetnnThanks in advance, have a great week!nnValenjinn

[Rob]

You'd either fix the flow rate (normally done) or the inlet pressure. You just need to work out the inlet velocity as a function of time. Expressions will do the job, as will a UDF, DEFINE_PROFILE.

[Valenjin]

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Hey Rob,

thanks for the reply! I have one more question maaaaybe you can help me out on this too.

In all the tutorials i see that i can select Carreau as the visocity model. However i cannot find it in my ansys and also i cant find anywhere if it is an addin that i need to download. Do you know anything about that?

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[Rob]

Turn the turbulence (viscous) model to laminar. NonNewtonian viscosity and turbulence does work together but is physically somewhat dubious. You can reactivate it, but I'll leave you to find the commands in the manual (which do come with some warnings). Blood flow is laminar, but expect to have some discussions with the medical community about that: they have a different definition for turbulence.

[Valenjin]

You are my hero Rob! Enjoy your evening.

[Rob]

Thanks, you too. Some bedtime reading for you:
Gijsen F.J.H., van de Vosse F.N., Janssen J.D.; 1999; The Influence of the non-Newtonian properties of blood on the flow in large arteries: steady flow in a carotid bifurcation model; Jou of Biomechanics, Vol 32, pp601

[jai_mann]

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Hi rob can you send me the link of the geometry of arteries

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[Rob]

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No. The terms we agreed to when we obtained the scan specifically covered where and how the geometry was to be used.

Materialise may have a geometry available as they were building a database of body parts for academic research. Otherwise you'll need a scan and software to extract the DICOM data: if the scanner doesn't do that Materialise and Simpleware produce software to do this.

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