# Difference between input flow rate and result flow rate

**URL:** https://discourse.paraview.org/t/difference-between-input-flow-rate-and-result-flow-rate/13046
**Category:** ParaView Support
**Tags:** vtk
**Created:** [October 16, 2023, 7:55am UTC](https://discourse.paraview.org/t/difference-between-input-flow-rate-and-result-flow-rate/13046 "2023-10-16T07:55:59Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![hyeonwoo](https://discourse.paraview.org/user_avatar/discourse.paraview.org/hyeonwoo/32/12480_2.png) [@hyeonwoo](https://discourse.paraview.org/u/hyeonwoo)
#### Post date: [October 16, 2023, 7:55am UTC](https://discourse.paraview.org/t/difference-between-input-flow-rate-and-result-flow-rate/13046/1 "2023-10-16T07:55:59Z")

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![image](https://discourse.paraview.org/uploads/default/original/2X/c/c66bc55c723cf92b952762537f71b7ab17e53752.png)  
 ![image](https://discourse.paraview.org/uploads/default/original/2X/4/43867c24b1172ca092af59cab3d037515b67fd66.png)  
 ![image](https://discourse.paraview.org/uploads/default/original/2X/a/aaa78f767cd8af0f6332abe776e11e8caedaad9d.png)  
The peak value of the input flow rate and the resulting flow rate.  
 ![image](https://discourse.paraview.org/uploads/default/original/2X/b/b7828f7b97652e6f5e34d46dd0bd349c36c14b52.png)  
 ![image](https://discourse.paraview.org/uploads/default/original/2X/5/5e652752cbc5bba1bf541e34458b5bfe8820848c.png)

Through Paraview, we checked whether the input flow rate matches the result flow rate. However, we saw a 2% decrease in the flow rate. Is there a way to solve this problem?

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### Author: ![mwestphal](https://discourse.paraview.org/user_avatar/discourse.paraview.org/mwestphal/32/17_2.png) [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [October 23, 2023, 11:28am UTC](https://discourse.paraview.org/t/difference-between-input-flow-rate-and-result-flow-rate/13046/2 "2023-10-23T11:28:30Z")

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How do you compute the flow rate externally of ParaView ?