Hi Tim,
thanks for your answer. Your method sound straight-forward. The only issue I
have now is that I'm simply not sure how to control the Calculator of paraview.
Following your steps, I want to set e.g.:
'Result Array Name': S_squared
and then compute using the calculator something like
(gradient(velocity) + transpose(gradient(velocity)))^2/2
but this gives me a calculator error ('Syntax Error: expecting a variable
name'). So I assume I'm simply using the calculator the wrong way (giving input
in an incorrect manor).
Could you specify how you give input to the calculator following your outlined
steps? Also, do you know the difference between the 'ComputeDerivative' and
'Gradient' is?
Thanks again for the help,
/David
<https://webmail.kth.se/owa/redir.aspx?C=IxWYxXymHES_fQvc4qU3B9BOtBARstEIlfcjHJ6nx0MeBY57EwkoSX2SdYQPib-GqeXHouLYnDA.&URL=mailto%3adavid.larsson%40sth.kth.se>
________________________________
Från: Tim Gallagher <[email protected]>
Skickat: den 7 december 2015 23:16
Till: tim gallagher
Kopia: [email protected]; David Larsson
Ämne: Re: [Paraview] Velocity field analysis - lambda2
For the sake of people years later who come across this thread, there is a typo
in my definition and it should be:
lambda_2 = S_ik S_kj + \Omega_ik \Omega_kj
Tim
________________________________
From: "Tim Gallagher" <[email protected]>
To: "David Larsson" <[email protected]>
Cc: [email protected]
Sent: Monday, December 7, 2015 5:11:30 PM
Subject: Re: [Paraview] Velocity field analysis - lambda2
David,
I haven't taken on lambda-2 yet, but I have been able to build a pipeline for
Q-Criterion. It looks something like:
Data -> CellDataToPointData (if it isn't already point data) ->
ComputeDerivatives (set the gradient option to vorticity and the tensor option
to strain) -> CellDataToPointData -> Calculator (compute |S|^2) -> Calculator
(compute |\Omega|^2) -> Calculator (compute Q-criterion)
Since lambda_2 = S_ik S_ij + \Omega_ik \Omega_kj, you can use the same
procedure and use just the standard calculators if you want to expand the
Einstein summation and plug them all.
Once I've done this, I save the set of 3 calculators as a custom filter. When I
use pvpython, I load my custom filter in the server manager and then use the
CD2PD and ComputeDerivatives filters as needed. The python calculator might be
a better way to do it, but I haven't tried that yet.
Tim
________________________________
From: "David Larsson" <[email protected]>
To: [email protected]
Sent: Monday, December 7, 2015 4:11:39 PM
Subject: [Paraview] Velocity field analysis - lambda2
Dear all,
I'm working with velocity vector fields over multiple time steps. I would like
to compute a number of entities for the velocity field - most importantly the
lambda2-scalar, but being relatively new to paraview I'm not really sure how to
do that.
I can do some simple modifications using the calculator but can't really find
my way to grad() or curl() etc. I guess the solution is going over to pvpython
(which would also be preferred with regards to doing automated analysis).
Does anyone have any experience with performing numerical analysis of vector
velocity fields in pvpython that could give some hints on how to get started?
Or does anyone even have performed lambda2-analysis on such?
I've seen some similar questions in the mail-list from before but can't seem to
find a conclusive answer, so I thought I'd give it a try myself.
Thanks for the help.
/David
<https://webmail.kth.se/owa/redir.aspx?C=IxWYxXymHES_fQvc4qU3B9BOtBARstEIlfcjHJ6nx0MeBY57EwkoSX2SdYQPib-GqeXHouLYnDA.&URL=mailto%3adavid.larsson%40sth.kth.se>
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Search the list archives at: http://markmail.org/search/?q=ParaView
Follow this link to subscribe/unsubscribe:
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