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 ----- Original Message ----- From: "David Larsson" <david.lars...@sth.kth.se> To: paraview@paraview.org 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 _______________________________________________ Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the ParaView Wiki at: http://paraview.org/Wiki/ParaView Search the list archives at: http://markmail.org/search/?q=ParaView Follow this link to subscribe/unsubscribe: http://public.kitware.com/mailman/listinfo/paraview
_______________________________________________ Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the ParaView Wiki at: http://paraview.org/Wiki/ParaView Search the list archives at: http://markmail.org/search/?q=ParaView Follow this link to subscribe/unsubscribe: http://public.kitware.com/mailman/listinfo/paraview