i am simulating a pulsatil blood flow inside abdominal aortic aneurysm AAA witch is unsteady (cardiaque cycle ) , Fluent gives differents parametres ( velocity , pressure , wall shear stress WSS... ) at each time steps ,but i want to calculate OSI oscilating shear index witch depends on the mean and the magnitude of WSS wall shear stress in the cardiaque cycle ... is there a way i can do to calculate OSI in Fluent ?
Hi Belkacemi. As far as I know, most of the researchers calculate the OSI in the post processing stage by developing Matlab or other programming codes. But, recently I saw a PhD thesis (NTU, Singapore) that they calculate the OSI by using UDF macros. However, I didn’t check it but it must work properly. You can download the full thesis by the following link (see the page 168).
https://repository.ntu.edu.sg/handle/10356/48910
Please let me know the result if you run it in your case.
Hi Siamak . Thanks you i downloaded it, i think that i have to check it ... ok when i run it i contact you .
hi Belkacemi Djelloul , I would be happy to know if you solve the problem with the simulation. Because I'm trying to get the OSI and the variables mentioned in fluent or in cfx in ansys 18.1
Hi Carlos Alberto Torres Martinez,
I solved the problem by writing a Matlab script to calculate the OSI. I don't know if it was added in the recent versions of Ansys or not...
Thank you very much for your answer, I'm trying to solve it, it seems that if it could be done, I'm just having problems with how to enter a variable in cfx-pre. I will keep you informed of any progress if I can solve it.
Hi Carlos Alberto,
Thank you so much. So it was intregrated in the cfx?
Yes i this function by placing a configuration in cfx-pre,
AA=((Wall Shear X)^2+(Wall Shear Y)^2+(Wall Shear Z)^2)^0.5
OSI=0.5 * (1 - ((((Wall Shear X.Trnavg)^2 + (Wall Shear Y.Trnavg)^2 + (Wall Shear Z.Trnavg)^2)^0.5) / (AA.Trnavg))).
provided by Foad Kabinejadian
I am currently having difficulties when trying to add this part to the equation (AA.Trnavg), everything else allows me to enter it, I will try it for different options.
Hi Carlos Alberto Torres Martinez , did you find a solution to the difficulties you were having when trying to add AA.Trnavg to the equation? I am also having trouble doing that. Cheers, Bruno
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