[Paraview] How does Paraview calculate the velocity gradient
Hi, How does Paraview calculate the velocity gradient if I use filter "gradient of unstructured data set"? And what is the difference between using cell data and point data as input? For my case I am simulating an oscillatory flow inside a narrow channel, I would like to obtain the velocity gradient in order to calculate the shear stress across the channel. I applied the filter "gradient of unstructured data set" and use cell data as input. The results are reasonable for most region in the channel except for the velocity gradient in the first near-wall cell. The value is about half the analytical solution. Why is that? Many thanks, Wilson ___ 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
Re: [Paraview] Interpolation error in paraview
Hi, Besides the question below, is the filter "point interpolation" is used for more advanced interpolation scheme? Can I use this filter to obtain more accurate interpolation result? Anyone who could explain this filter to me? I just couldn't find any tutorial on this filter. Many thanks, Wilson From: HongchaoWang [mailto:hongchao.wang2...@gmail.com] Sent: Friday, 18 August 2017 11:37 AM To: 'paraview@paraview.org' <paraview@paraview.org> Subject: Interpolation error in paraview I'm just wondering what interpolation scheme is used for data manipulation in Paraview? I'm using Paraview 5.2.0. I want to measure the velocity very close to a wall surface so that I can obtain the wall shear stress. However, I found the velocity measured using Paraview is different from the results I have obtained using the postprocessing tool in OpenFoam. Compared with the analytical solution which is already known in my case, Paraview result is worse and is 10% smaller than the analytical solution while the OpenFoam result agrees with the analytical solution very well. With finer mesh, the difference between the Paraview and OpenFoam results becomes smaller, so I believe the difference is due to the interpolation error. Anyone who has experience on this problem? Is there any advanced interpolation scheme that I can use in Paraview? Many thanks, Wilson ___ 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
[Paraview] Interpolation error in paraview
I'm just wondering what interpolation scheme is used for data manipulation in Paraview? I'm using Paraview 5.2.0. I want to measure the velocity very close to a wall surface so that I can obtain the wall shear stress. However, I found the velocity measured using Paraview is different from the results I have obtained using the postprocessing tool in OpenFoam. Compared with the analytical solution which is already known in my case, Paraview result is worse and is 10% smaller than the analytical solution while the OpenFoam result agrees with the analytical solution very well. With finer mesh, the difference between the Paraview and OpenFoam results becomes smaller, so I believe the difference is due to the interpolation error. Anyone who has experience on this problem? Is there any advanced interpolation scheme that I can use in Paraview? Many thanks, Wilson ___ 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
Re: [Paraview] How to output forces over time?
I have solved the problem myself. I have chosen the wrong field association when outputting the data. Regards, Wilson From: HongchaoWang [mailto:hongchao.wang2...@gmail.com] Sent: Monday, 29 May 2017 4:13 PM To: 'paraview@paraview.org' <paraview@paraview.org> Subject: How to output forces over time? Hi, I am using paraview to postprocess the results from OpenFoam. I am able to calculate the drag and lift forces on a fixed box by integrating pressure over the box surface. Now I would like to output the time history of the of the forces. How can I achieve that? What I have done is to select the row of forces generated in the spread sheet view and then use "File->save data-> Write All Time Steps" . However, the output file only give me the results of p, U, normals, etc. without the forces I want. Does anyone know the solution to this problem? Many thanks, Wilson ___ 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
[Paraview] How to output forces over time?
Hi, I am using paraview to postprocess the results from OpenFoam. I am able to calculate the drag and lift forces on a fixed box by integrating pressure over the box surface. Now I would like to output the time history of the of the forces. How can I achieve that? What I have done is to select the row of forces generated in the spread sheet view and then use "File->save data-> Write All Time Steps" . However, the output file only give me the results of p, U, normals, etc. without the forces I want. Does anyone know the solution to this problem? Many thanks, Wilson ___ 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
[Paraview] How to save data for selected time range in paraview
Hi, I am using paraview to postprocess the results from openfoam. I am doing a 3D case and thus the cell number is huge. What I want to do is to save data from ''plot over line'' for a time frame from 23s to 28s. However, the "save data" option seems to only either save the current time step or all time steps. Does anyone know how to save data for selected time range or if someone could tell me how to load data for a selected time directories? Thanks in advance. Best regards, Wilson ___ 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
