Re: [deal.II] Facilities for computing the "goodness" of a mesh (i.e. something like a mesh-quality indicator)

On 1/15/20 10:42 AM, Krishnakumar Gopalakrishnan wrote: > > Thank you. This is certainly looking useful.  Do we have any example usage of > this function? For example, how do we re-compute the mesh based on the return > value from this aspect_ratio function or something? Other than the

Re: [deal.II] Using solution on from one FE problem as a boundary condition for another

Hey Ernesto, I’ve used the approach outlined by Wolfgang and Daniel in my own work (multi physics problems, single DoFHandler with BC’s being transferred between a primary and secondary problem solved on subsets of the domain). Overall, it works really well so I’d back up their suggestion and

Re: [deal.II] Facilities for computing the "goodness" of a mesh (i.e. something like a mesh-quality indicator)

Dear Krishna, There is also this long-standing pull request https://github.com/dealii/dealii/pull/8196 that hooks into the Verdict library to do mesh quality assessment. One day, hopefully in the not too distant future, I’ll get back to integrating

Re: [deal.II] discontinous contour over elements

Bruno, Thanks for your explanation. Indeed, the gradient of velocity, vorticity, will be discontinuous over C0 elements. I will give a try and do a L2 projection. Surprisingly I did not experience it in my code before. I used standard Lagrangian shape functions and continuous Galerkin method.

Re: [deal.II] discontinous contour over elements

Professor Bangerth, Thanks for the hints. I almost got what you mean. I will try to perform a L2 projection. Regards David From: dealii@googlegroups.com on behalf of Wolfgang Bangerth Sent: Thursday, January 16, 2020, 1:03 AM To: dealii@googlegroups.com

Re: [deal.II] Facilities for computing the "goodness" of a mesh (i.e. something like a mesh-quality indicator)

Hi Martin, Thank you. This is certainly looking useful. Do we have any example usage of this function? For example, how do we re-compute the mesh based on the return value from this aspect_ratio function or something? Krishna On Wednesday, January 15, 2020 at 5:31:34 PM UTC, Martin

Re: [deal.II] Facilities for computing the "goodness" of a mesh (i.e. something like a mesh-quality indicator)

Dear Krishna, We have recently added one such function, namely GridTools::compute_aspect_ratio_of_cells(), https://dealii.org/developer/doxygen/deal.II/namespaceGridTools.html#a2a9d8801d952ea8afa9ec1573229a329 Best, Martin On 15.01.20 18:26, Krishnakumar Gopalakrishnan wrote: In the

[deal.II] Facilities for computing the "goodness" of a mesh (i.e. something like a mesh-quality indicator)

In the results/extension section of Step-6 as well in Step-49, there is a great deal of discussion about obtaining good meshes are for a problem, with the caveat that this is a highly specialized topic. Step-49 is full of warnings about things that can go wrong when applying certain

Re: [deal.II] discontinous contour over elements

An easy way to carry the projection that Wolfgang suggested is to use an L2 projection. The L2 projection matrix is only a mass matrix and your right hand side is constructed by the integral of multiplication of the variable you want to project with the test function. Generally, this matrix is

Re: [deal.II] discontinous contour over elements

On 1/15/20 9:22 AM, David Eaton wrote: > I understand the C0 element is piecewise linear across elements. However, I > did not experience the same issue in my own C++ code while I use C0 element > with the Petrov Galerkin stabilization terms. Actually, I am very confused at > this point. How

Re: [deal.II] discontinous contour over elements

I understand the C0 element is piecewise linear across elements. However, I did not experience the same issue in my own C++ code while I use C0 element with the Petrov Galerkin stabilization terms. Actually, I am very confused at this point. How could I get rid of it while using C0 element?

Re: [deal.II] discontinous contour over elements

On 1/14/20 10:04 PM, David Eaton wrote: > > Thank you for your suggestions. I am going to take a look at Lethe and > compare > with my implementation. In stabilized formulation, I used quadrilateral > element, instead of P2 P1 Taylor-Hood element. The used element is only C0 > element. I also

[deal.II] Different shape representations with manifolds on the same triangulation

Dear all, I would like your guidance on how to perform the assembly of different shape representations on the same triangulation and on the same loop through cells. Let me try to explain a bit more. I have designed a grid containing two concentric squares (or circles). Additionally, I have a