[Paraview] PV 3.10.1 computing vorticity from vector field

Thu Jun 2 15:57:13 EDT 2011

This is outside of what I usually do, so I may not be much help. But once you have the vorticity at all verticies, that should include the verticies on the cylinder surface. 

How do you extract the surface? Is it a body fitted grid or an embedded boundary/levelset to mark it? I would assume if you extract the surface in the pipeline downstream of the derivatives and interpolation filters, all of the variables would be available on the surface. 

Unless of course the surface is looking for cell data and not point data, in which case you would skip the second interpolation filter. 

Tim 

----- Original Message -----
From: "Stephen Wornom" <stephen.wornom at inria.fr> 
To: agagliardi at ara.co.uk 
Cc: "ParaView list" <paraview at paraview.org>, "Andy Bauer" <andy.bauer at kitware.com>, gtg085x at mail.gatech.edu 
Sent: Thursday, June 2, 2011 3:18:29 PM 
Subject: Re: [Paraview] PV 3.10.1 computing vorticity from vector field 

----- Original Message -----

From: "Adriano Gagliardi" <agagliardi at ara.co.uk> 
To: "Andy Bauer" <andy.bauer at kitware.com>, gtg085x at mail.gatech.edu, "stephen wornom" <stephen.wornom at inria.fr> 
Cc: "ParaView list" <paraview at paraview.org> 
Sent: Thursday, June 2, 2011 7:11:36 PM 
Subject: RE: [Paraview] PV 3.10.1 computing vorticity from vector field 

On this subject, it should also be possible to use the Python Calculator to perform this function. Create a vector, U and obtain the curl of it by using: curl(U). I think your version of Python must have numpy available, though. 

I tried both the suggestion of Time and Andy, both worked well. Now that I have the vorticity at all the vertices. What must I do to obtain the surface flow (vorticity) and surface vectors? The solution is for the Navier-Stokes equations for flow over a cylinder. I know how to extract the surface of the cylinder but how do I tell PV to use the vorticity and not the velocity field? 
Hope my quest is clear, 
Stephen 

<blockquote>

=================================== 

Adriano Gagliardi MEng PhD 
Business Sector Leader 
Computational Aerodynamics 
Aircraft Research Association Ltd. 
Manton Lane 
Bedford 

Tel: 01234 32 4644 
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From: paraview-bounces at paraview.org [mailto:paraview-bounces at paraview.org] On Behalf Of Andy Bauer 
Sent: 02 June 2011 17:42 
To: gtg085x at mail.gatech.edu; stephen.wornom at inria.fr 
Cc: ParaView list 
Subject: Re: [Paraview] PV 3.10.1 computing vorticity from vector field 

For computing vorticity, depending on the grid type you can also use the Gradient of Unstructured Datasets filter. There is an option to compute vorticity for 3 component arrays (i.e. velocity). It works on both point data and cell data and the output will be the same type of field data. I'm about to change this filter so that it will work with all types of VTK grids. 

Andy 

On Thu, Jun 2, 2011 at 12:29 PM, Tim Gallagher < tim.gallagher at gatech.edu > wrote: 

<blockquote>
The output from the ComputeDerivatives is Cell Data. To do those things, you want to make it Point Data with another CellDataToPointData filter. 

The calculator would see it if you changed it from point data to cell data. But since you want to do other stuff with it, add the interpolation filter again and then it will appear with the rest of your point data. 

Tim 

----- Original Message ----- 
From: "Stephen Wornom" < stephen.wornom at inria.fr > 

To: gtg085x at mail.gatech.edu 
Cc: "ParaView list" < paraview at paraview.org > 
Sent: Thursday, June 2, 2011 12:26:04 PM 
Subject: Re: [Paraview] PV 3.10.1 computing vorticity from vector field 

Tim Gallagher wrote: 
> 1. If it's cell centered data, apply the CellDataToPointData filter. If it's point data, skip this step 
> 2. Apply the ComputeDerivatives filter. Choose your velocity vector as the Vectors argument, set the Output Vector Type to Vorticity. I usually also set Output Tensor Type to nothing unless you need it. 
> 3. Hit apply. 
> 
Works correctly but what must I do to: 
1 make a vector or contour plot 
2 tracer plot or vorticity lines (like streamlines) plot? 
The choice for these is only the velocity field that I read. 
Calculator does not see the vorticity vector that was created. 
Thanks for you help, 
Stephen 
> Tim 
> 
> ----- Original Message ----- 
> From: "Stephen Wornom" < stephen.wornom at inria.fr > 
> To: paraview at paraview.org 
> Sent: Wednesday, June 1, 2011 10:55:12 AM 
> Subject: [Paraview] PV 3.10.1 computing vorticity from vector field 
> 
> What are the steps to compute the vorticity vector from the velocity vector? 
> Stephen 
> 
> 

-- 
stephen.wornom at inria.fr 
2004 route des lucioles - BP93 
Sophia Antipolis 
06902 CEDEX 

Tel: 04 92 38 50 54 
Fax: 04 97 15 53 51 

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