# Oscillatory Shear Index (OSI)
**URL:** https://discourse.paraview.org/t/oscillatory-shear-index-osi/6106
**Category:** ParaView Support
**Created:** [December 21, 2020, 6:19pm UTC](https://discourse.paraview.org/t/oscillatory-shear-index-osi/6106 "2020-12-21T18:19:01Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@Andrea\_Impiombato](https://discourse.paraview.org/u/Andrea_Impiombato)
#### Post date: [December 21, 2020, 6:19pm UTC](https://discourse.paraview.org/t/oscillatory-shear-index-osi/6106/1 "2020-12-21T18:19:01Z")
very kind readers,
I have a 3D geometry (aorta) where I must to calculate the OSI index. The time integrals of Wall Shear Stress must be evaluated for the calculation.
How can I calculate with Paraview these integrals? Is it possible?
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### Author:  [@Benny\_Loretoni](https://discourse.paraview.org/u/Benny_Loretoni)
#### Post date: [September 21, 2022, 10:13am UTC](https://discourse.paraview.org/t/oscillatory-shear-index-osi/6106/2 "2022-09-21T10:13:12Z")
Hi, have you found any solution for this matter? We got the same problem with the same kind of geometry.
Thank you, let us know
Best regards,
Benedetta
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### Author:  [@Kenneth\_Moreland](https://discourse.paraview.org/u/Kenneth_Moreland)
#### Post date: [September 21, 2022, 1:42pm UTC](https://discourse.paraview.org/t/oscillatory-shear-index-osi/6106/3 "2022-09-21T13:42:46Z")
I believe no one has responded to this question because no one watching this ParaView list knows what OSI is or how to calculate it (that is certainly the case for me), and there is not enough detail in the question to answer it.
It would help to ask a more targeted question. I note that the original question asked about time integrals of wall shear stress. It would help to understand what exactly is meant about a time integral (a summation of field values over time?) and examples of the data being operated on.
Because I don’t know what OSI is, I Googled it a bit. I ran across a paper (DOI [10.33160/yam.2020.11.013](https://doi.org/10.33160/yam.2020.11.013)) that reports computing OSI with ParaView. So, this certainly seems possible. I don’t see enough detail in the paper to completely replicate the process. It might be possible to reach out to the authors to get more detail if necessary.
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### Author:  [@Gening\_Dong](https://discourse.paraview.org/u/Gening_Dong)
#### Post date: [May 6, 2023, 1:47am UTC](https://discourse.paraview.org/t/oscillatory-shear-index-osi/6106/4 "2023-05-06T01:47:06Z")
Hi @Kenneth_Moreland ,
I’m facing the same problem here. The OSI is defined as follow:
I was able to calculate the absolute value of WSS and use `IntegrateVariables` to get the time integration. However, I don’t know how to do further calculations using the integrated variables. Can I use `Calculator`? But I don’t see any scalar nor vectors there.
Thanks,
Gening
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### Author:  [@Kenneth\_Moreland](https://discourse.paraview.org/u/Kenneth_Moreland)
#### Post date: [May 8, 2023, 3:29pm UTC](https://discourse.paraview.org/t/oscillatory-shear-index-osi/6106/5 "2023-05-08T15:29:20Z")
I’m not sure what issue you are having. You should be able to apply `Calculator` to the output of `Integrate Variables`. I just tried it in ParaView 5.11.1, and I was able to access the fields just fine. Are you sure you have the `Attribute Type` (`Point Data` or `Cell Data`) correct?
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### Author:  [@Gening\_Dong](https://discourse.paraview.org/u/Gening_Dong)
#### Post date: [June 10, 2023, 12:02am UTC](https://discourse.paraview.org/t/oscillatory-shear-index-osi/6106/6 "2023-06-10T00:02:54Z")
Thanks for the reply! I just figured out I completely got this wrong. The `Integrate Variables` is used to integrate over the elements/blocks, but not a temporal integral. So the problem becomes, is there a way to calculate a temporal integral? I tried `Plot Data Over Time` but I’m not sure what does q1, q2, and q3 mean. Is anyone of those a temporal integral?
Thanks,
Gening