- Nektar-users - imperial.ac.uk

NekMesh error message with mcf type file
by Eli Frydman 20 Jan '21

20 Jan '21

******************* This email originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email stamping for this address. ******************* Hi all, I tried to get a mesh for the naca airfoil example in the directory nektar++-5.0.0/utilities/NekMesh/Tests/MeshGen/NACA using the command : NekMesh -v 2d_bl.mcf mesh.xml But i got the following error message: terminate called after throwing an instance of 'Nektar::ErrorUtil::NekError' what(): Level 0 assertion violation No such module: Input: mcf Can you please help me with this issue. Thank you Mr Frydman

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Power Kernel
by Vishal Saini 17 Jan '21

17 Jan '21

******************* This email originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email stamping for this address. ******************* Hi all, Hope you're keeping well. I was trying to understand the working of the Power Kernel in the context of SVV. The input coefficient related to this kernel is to be scaled by *a*h/P* (according to Moura's original paper) where *a* is some measure of local elemental velocity and *h/P* gives local mesh size. So, I ventured into VelocityCorrectionScheme.cpp. Now, 1. I could see where *h/P* is multiplied but not *a *(I imagined that *a* would vary in space but seems like a=1 for the whole domain). Could someone kindly point out where that would be? 2. I noticed that the said scaling takes place just once, in the beginning of the simulation. Is that correct? Thank you in advance. --- *Vishal SAINI*

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Filters Time writing problem
by Moto Light 07 Jan '21

07 Jan '21

******************* This email originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email stamping for this address. ******************* Hi all, happy new year for all of you, Just a small question. Whenever I am using filters like (AeroForces) or using probes and set the OutputFrequancy =1 sometimes the written files are repeating time in the output, please see the forces file written data. <FILTER TYPE="AeroForces"> <PARAM NAME="OutputFile">stats/stats4/CylinderForces3D</PARAM> <PARAM NAME="OutputFrequency">*1*</PARAM> <PARAM NAME="Boundary"> B[6] </PARAM> </FILTER> //////////////////////////////////// the written forces file looks like # Time F1-press F1-visc F1-total F2-press F2-visc F2-total 1821.08 4.1827904 0.4123355 4.5951259 0.45330259 -0.49524554 -0.041942954 1821.08 4.5897777 0.4169459 5.0067236 0.5086121 -0.49606064 0.012551456 1821.08 3.2548159 0.41033032 3.6651462 0.39509326 -0.4935032 -0.098409937 1821.08 4.6163333 0.41190927 5.0282425 0.37645971 -0.49545957 -0.11899986 1821.08 4.01314 0.41139674 4.4245367 0.52263137 -0.4956953 0.026936074 As you see the written time is fixed and after 15 steps changes to be 1821.09, can we control the written time to increase the number of floating digits written by filters. Regards, Reda

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FieldConvert -m gradient seg-fault
by G. D. McBain 04 Jan '21

04 Jan '21

******************* This email originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email stamping for this address. ******************* I'm just starting to learn Nektar++ from the tutorials and User Guide and mostly it's going very well, but I'm having trouble with FieldConvert -m gradient, hitting a segmentation fault. I'm wondering whether I'm misunderstanding its use. For example, after successfully running the basics-helmholtz example https://doc.nektar.info/tutorials/latest/basics/helmholtz/basics-helmholtz.… gmsh -2 Helm_mesh.geo Nekmesh Helm_mesh.msh Helm_mesh.xml ADRSolver -v Helm_mesh.xml Helm_conditions.xml FieldConvert Helm_mesh.xml Helm_conditions.xml Helm_mesh.fld Helm_mesh.vtu to produce Helm_mesh.fld and Helm_mesh.vtu, I tried FieldConvert -m gradient Helm_mesh.xml Helm_conditions.xml Helm_mesh.fld Helm-grad.fld following the documentation at https://doc.nektar.info/userguide/latest/user-guidese22.html#x35-1480005.5.… but this raised [levy:58744] *** Process received signal *** [levy:58744] Signal: Segmentation fault (11) [levy:58744] Signal code: Address not mapped (1) [levy:58744] Failing at address: 0xb0 [levy:58744] [ 0] /lib/x86_64-linux-gnu/libc.so.6(+0x3f040)[0x7f9d682b1040] [levy:58744] [ 1] /usr/lib/x86_64-linux-gnu/libFieldUtils.so.5.0.0(_ZN6Nektar10FieldUtils11ProcessGrad7ProcessERN5boost15program_options13variables_mapE+0x6cc)[0x7f9d6a1aa7ac] [levy:58744] [ 2] FieldConvert(_Z9RunModuleSt10shared_ptrIN6Nektar10FieldUtils6ModuleEERN5boost15program_options13variables_mapEb+0x3f)[0x55c3dbf99b8f] [levy:58744] [ 3] FieldConvert(main+0x176c)[0x55c3dbf95e5c] [levy:58744] [ 4] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe7)[0x7f9d68293bf7] [levy:58744] [ 5] FieldConvert(_start+0x2a)[0x55c3dbf9956a] [levy:58744] *** End of error message *** Segmentation fault (core dumped) That's on Ubuntu 18.04, where I had installed nektar++ from http://www.nektar.info/ubuntu-bionic bionic/contrib, but I also get the same error on CentOS 7.7.1908, using the docker image nektarpp/nektar:244f4842. What I was wanting to use the gradient module in my own project fpr was having solved for a steady incompressible potential flow with ADRSolver (EQTYPE "Laplace") to compute the velocity field as the gradient of the potential. Thank you, Geordie McBain Sent from [ProtonMail](https://protonmail.com), Swiss-based encrypted email.

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how to extract the heat flux along a wall
by ztdepyahoo 21 Dec '20

21 Dec '20

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Regarding boundary condition from file
by Abhishek Kumar 13 Dec '20

13 Dec '20

******************* This email originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email stamping for this address. ******************* Dear friends, I am trying to use boundary conditions from a file. I followed section "3.3.5.5" of the user guide, and attempted the example of "ChanFlow2D_bcsfromfiles.xml". Code runs perfectly with the given boundary of the .bc files. However, I am struggling to create a ".bc" file. How are the ".bc" files created for "ChanFlow2D_bcsfromfiles.xml" example? Is it possible to use ASCII data in the ".bc" files? With regards Abhishek -- --------------------------------------------------------------------------------------- Abhishek Kumar Assistant Professor (Research) Centre for Fluid and Complex Systems Coventry University, Coventry CV15FB The United Kingdom Phone: +44 24 7765 9150 Mobile: +44 7464026494 ---------------------------------------------------------------------------------------

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Outflow BC for buoyant flows
by Sartaj Tanweer 13 Dec '20

13 Dec '20

******************* This email originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email stamping for this address. ******************* Dear all, I am using Nektar++(4.4.1) for computations of the flow past a square cylinder placed near a moving wall under the influence of buoyancy. I have used *"HOutflow*" boundary condition at the outlet as suggested by the user guide, but I got the wrong result. Could someone please suggest a right BC at the outlet? I have attached the mesh and condition files and the resultant streamlines. with best regards, Sartaj Tanweer

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Help MESHGEN
by Octavio Morales 13 Dec '20

13 Dec '20

******************* This email originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email stamping for this address. ******************* Hi again, I am trying to use the Mesh Generation option by setting the NEKTAR_USE_MESHGEN option to ON but when I try to compile it this pops up

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Boundary layer splitting
by Vishal Saini 13 Dec '20

13 Dec '20

******************* This email originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email stamping for this address. ******************* Hi all, Quick question: The user guide (v5.0) states: " To split a prism boundary layer on surface 11 into 3 layers with a growth rate of 2 and 7 integration points per element use the following: NekMesh -m bl:surf=11:layers=3:r=2:nq=7 MeshOnePrismLayer.xml Mesh3PrismsLayers.xml " What would be the correct nq when using, say, <E COMPOSITE="C[1]" NUMMODES="5" FIELDS="u,v,w" TYPE="MODIFIED" /> <E COMPOSITE="C[1]" NUMMODES="4" FIELDS="p" TYPE="MODIFIEDQUADPLUS1" />? I am confused because (a) different poly order in *u* and p and (b) I am using dealiasing and not sure if the "integration points" above would include the extra integration points or not. Thank you for your time. --- *Vishal SAINI*

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Error in installation: version `GLIBCXX_3.4.26' not found (required by /lib/x86_64-linux-gnu/libapt-pkg.so.6.0)
by Hamed Faghanpourganji 01 Dec '20

01 Dec '20

******************* This email originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email stamping for this address. ******************* Dear friends, I have tried to install Nektar++ on Ubuntu, but I got the noted error in subject of this Emial. I already google it, but following links didn't help https://unix.stackexchange.com/questions/456918/how-do-i-install-glibcxx https://github.com/ufo-project/ufochain/issues/3 https://askubuntu.com/questions/1166292/version-glibcxx-3-4-26-not-found-ev… Anyone can help me with the installation? Thank you very much in advance. Kind regards, Hamed <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campai…> Virusvrij. www.avast.com <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campai…> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

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