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Old   February 24, 2015, 11:17
Default Colour by turbulence intensity?
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Hello all,

Does anybody know how I can colour a slice by turbulence intensity? For example in the U0 direction: I have UPrime2Mean:0 and I have UMean:0, although I want to somehow get the paraView to compute the TI = (SQRT(UPrime2Mean)/UMean) and then colour the slice based on these values?

I'm relatively new to paraview so have tried but can't seem to crack this one.

Best wishes,
D
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Old   February 25, 2015, 09:44
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Hi D,

This sounds like you would need the calculator filter.

Filters>alphabetical>Calculator

Or click on the calculator filter icon.

Than use the scalar UPrime2Mean_X (or Y or Z) and the corresponding scalar UMean_X (or Y or Z) as the function. The result should read TI.

Or do you want to have the magnitude of the mean and variance? In that case use mag(UPrime2Mean) and mag(UMean).

Hope this helps.

Regards,
Tom
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Old   February 25, 2015, 10:39
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Quote:
Originally Posted by tomf View Post
Hi D,

This sounds like you would need the calculator filter.

Filters>alphabetical>Calculator

Or click on the calculator filter icon.

Than use the scalar UPrime2Mean_X (or Y or Z) and the corresponding scalar UMean_X (or Y or Z) as the function. The result should read TI.

Or do you want to have the magnitude of the mean and variance? In that case use mag(UPrime2Mean) and mag(UMean).

Hope this helps.

Regards,
Tom

Hi tom, Thank you for the reply. I'm having some issues with the solution. I've attached a screen shot of my error message and the formula you can see I'm trying to us in the calculator.

I'm basically trying to calculate the Turbulence Intensity at points on a slice. I'm trying to compute the TI using the UPrime2Mean:0 and UMean:0.

What i'm after is for the post processor to calculate the TI for all the points on the slice, and then I'm hoping to colour that slice using the TI results.

Any ideas?
Attached Images
File Type: jpg ParaView Calculator Help.jpg (54.5 KB, 17 views)
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Old   February 25, 2015, 11:15
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Tom Fahner
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From your screenshot I cannot read the function. Can you just literally copy it here? Maybe use the Code tags like I did below.

Based on what I can see I think it should be:

Code:
sqrt(UPrime2Mean_XX)/UMean_X
Also in the Result Array Name box you should specify TI instead of Result.

Last edited by tomf; February 25, 2015 at 11:16. Reason: Remark about TI vs Result
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Old   February 25, 2015, 11:19
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Quote:
Originally Posted by tomf View Post
From your screenshot I cannot read the function. Can you just literally copy it here? Maybe use the Code tags like I did below.

Based on what I can see I think it should be:

Code:
sqrt(UPrime2Mean_XX)/UMean_X
Also in the Result Array Name box you should specify TI instead of Result.
I've used the same code as above: sqrt(UPrime2Mean_XX)/UMean_X

although my error message reads as follows:

ERROR: In /gpfs/apps/OpenFOAM/ThirdParty-2.1.1/ParaView-3.12.0/VTK/Common/vtkFunctionParser.cxx, line 1480
vtkFunctionParser (0x145790fb0): Syntax error: operator expected; see position 18

ERROR: In /gpfs/apps/OpenFOAM/ThirdParty-2.1.1/ParaView-3.12.0/VTK/Common/vtkFunctionParser.cxx, line 1480
vtkFunctionParser (0x145790fb0): Syntax error: operator expected; see position 18

Warning: In /gpfs/apps/OpenFOAM/ThirdParty-2.1.1/ParaView-3.12.0/VTK/Graphics/vtkArrayCalculator.cxx, line 401
vtkPVArrayCalculator (0x145c199f0): An error occured when parsing the calculator's function. See previous errors.
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Old   February 26, 2015, 04:50
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Tom Fahner
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I see you are using version 3.12.0 of ParaView, maybe this was a bug in that version, could you try using the latest ParaView (4.3.1)? The error message seems to indicate it needs an operator at the _XX position, but that does not really make sense to me.
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