# Calculate WSS from 2D velocity data

**URL:** https://discourse.paraview.org/t/calculate-wss-from-2d-velocity-data/10981
**Category:** ParaView Support
**Created:** [December 15, 2022, 1:18am UTC](https://discourse.paraview.org/t/calculate-wss-from-2d-velocity-data/10981 "2022-12-15T01:18:00Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![Ms1](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/m/2bfe46/32.png) [@Ms1](https://discourse.paraview.org/u/Ms1)
#### Post date: [December 15, 2022, 1:18am UTC](https://discourse.paraview.org/t/calculate-wss-from-2d-velocity-data/10981/1 "2022-12-15T01:18:00Z")

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Hi! I am trying to calculate Wall Shear Stress from 2D PIV data. I have the following scalar data for my mesh:(x coordinate, y coordinate, x component of velocity, y component of velocity). I have calculated a simple velocity magnitude using sqrt(Vx^2+Vy^2). I read that you should be able to calculate a velocity gradient and multiply by normals and viscosity to get WSS, however I get all 0 values when I do this. Could someone walk me through how to calculate WSS using this data?

Also, is there a way that I can convert the scalar Vx and Vy data into true vectors so I can use it to orient my 2D glyphs? I’m very new to paraview, so any help is appreciated. Thanks!