February 2020 - Nektar-users

Element with max CFL
by Vishal Saini 02 Apr '20

02 Apr '20

Hi all, Quick question: Has anyone tried to check the location of a particular element in the mesh? A log file reports the maximum (?) CFL and the corresponding element as: "CFL: 0.0337915 (in elmt 94488)"? Is there a quick way to locate "elmt 94488"? Cheers, Vishal

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Manipulate 3DH1 chk/fld file in Fourier space
by F Mellibovsky 16 Mar '20

16 Mar '20

Dear all, I have run a 3DH1 simulation and I need to set all Fourier coefficients to zero except those corresponding to a fundamental wavelength and its harmonics (e.g. keep only modes 0, +-5, +-10, etc and set all the rest to zero). I have the intuition that some combination of FieldConvert options can accomplish exactly this, but I am unsure of what is the best (or some) way to proceed. My guess is that the "homplane:wavespace:planeid=?" can be used to extract the individual Fourier modes, but I am unsure as to how the Fourier modes are sorted and which ones must be extracted to recover a chosen fundamental wavelength and its harmonics (both real and imaginary parts, or modulus and argument, or however the Fourier modes are stored). The only one I'm pretty sure of is mode 0 or mean mode. Once I get the individual fld files for each one of the modes, I was intending to use the "addfld:fromfld=mode1.fld:scale=1 mode1.xml mode2.fld newfile.fld" sequentially to build a solution from the chosen modes. The issue here is that the fields extracted with "homplane" seem to be 2D and would therefore need to be recast in 3DH1 form before proceeding to "addfld". How can this be done? Thanks in advance for your help Fer Mellibovksy

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Re: [Nektar-users] VIV flow past a cylinder
by Wang, Zhicheng 27 Feb '20

27 Feb '20

Vijay, thanks a lot. I have figured it out. I solve the oscillator equation in physical space and replace the newmark-beta scheme with the one we have in the old Nektar. now the displacement looks correct, please see the attached. On Thu, Feb 27, 2020 at 12:04 AM VIJAY KUSHWAHA <bijay8833(a)sjtu.edu.cn> wrote: > Hi Zhicheng, > 1. The structural stiffness parameter(StructStiff) is not defined in your > .xml file. Instead you have defined that term in cable tension. > 2. StructRho(m/rho*D^2) is the non-dimensional mass. For mass ratio to be > defined as 2.0, you need to define it accordingly. > Try with these parameters. > Cheers, > Vijay Kushwaha > > ----- Original Message ----- > From: "Wang, Zhicheng" <zhicheng_wang(a)brown.edu> > To: "ybao" <ybao(a)sjtu.edu.cn> > Cc: "Sherwin, Spencer J" <s.sherwin(a)imperial.ac.uk>, "nektar-users" < > nektar-users(a)imperial.ac.uk>, "Lahooti, Mohsen" <m.lahooti(a)imperial.ac.uk>, > "VIJAY KUSHWAHA" <bijay8833(a)sjtu.edu.cn> > Sent: Wednesday, February 26, 2020 11:16:52 PM > Subject: Re: [Nektar-users] VIV flow past a cylinder > > Hi Mohsen and Yan, thanks for your reply. Please find the amplitude and > lift coefficient are attached below. The lift coef looks reasonable. > Personally, I have done tons of similar simulations using the predecessor > SEM code Nektar, usually, VIV simulation is not sensitive to quadrature > points, aliasing error.... I will look at the code. Please let me know if > you get a chance to find out the mistakes in my parameter file. > > > On Wed, Feb 26, 2020 at 7:31 AM ybao <ybao(a)sjtu.edu.cn> wrote: > > > Hi Zhicheng, > > > > May you show me the time history of the cylinder vibration and lift > > coefficient for us? in NEKTAR++, the Euler beam model was employed to > > describe the vibration of the structure, so you need to check whether or > > not the values of tension, structure stiffness and bending stiffness are > > correct. recently Vijay, a graduate student in my group, have run 2D > > simulations and got correct results. > > > > Hi Vijay, can you have a look on the xml from Zhicheng? many thanks! > > > > Cheers, > > Yan > > > > On 26 Feb 2020, at 05:09, Wang, Zhicheng <zhicheng_wang(a)brown.edu> > wrote: > > > > Thank you Spencer. I will wait for Yan Bao or Mohsen's response. There > is > > no numerical instability issue for now, but thank you for the suggestion. > > > > On Tue, Feb 25, 2020 at 3:47 PM Sherwin, Spencer J < > > s.sherwin(a)imperial.ac.uk> wrote: > > > >> HI Zhicheng, > >> > >> I am forwarding your request to Yan Bao who is probably the most > >> experienced in this setup. Not sure if Yan is using the Nektar++ users > list > >> however. > >> > >> I would be inclined to use the SpectralVanishingViscosity with DGKernel > >> and Dealisasing if you get any flow instability issues. > >> > >> Cheers, > >> Spencer > >> > >> PS Mohsen might be able to help too. > >> > >> On 25 Feb 2020, at 15:05, Wang, Zhicheng <zhicheng_wang(a)brown.edu> > wrote: > >> > >> This email from zhicheng_wang(a)brown.edu 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 nektar++ users, > >> I wonder if there is anyone could check my simulation parameters for the > >> simulation of 2D vortex induced vibration (VIV) of flow past a cylinder > >> that is allowed to move in crossflow direction ? Here the cylinder is > >> rigidly mounted with a natural frequency f=0.17, mass per unit length > =2.0, > >> Re=100. For this particular case, the vibration amplitude is expected > to > >> be around 0.5D, but the simulation gave me 0.05D. So I think I must have > >> made some mistakes somewhere in the parameter file. The parameter file I > >> used is posted below. > >> > >> ****************************************************************** > >> <EXPANSIONS> > >> <E COMPOSITE="C[0]" BASISTYPE="Modified_A, Modified_A" > >> NUMMODES="3,3" POINTSTYPE="GaussLobattoLegendre, > >> GaussLobattoLegendre" > >> NUMPOINTS="5,5" FIELDS="u,v,w,p" /> > >> </EXPANSIONS> > >> > >> <CONDITIONS> > >> <SOLVERINFO> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> </SOLVERINFO> > >> > >> <PARAMETERS> > >> TimeStep = 0.005 > >> FinalTime = 1000 > >> NumSteps = FinalTime/TimeStep > >> IO_CheckSteps = 2000 > >> IO_InfoSteps = 25 > >> IO_CFLSteps = 25 > >> Re = 100 > >> > >> Kinvis = 1/Re > >> > >> HomModesZ = 2 > >> LZ = 0.01 > >> > >> FreqY = 0.17 > >> > >> OmegaY = 2.0*PI*FreqY > >> > >> StructStiff = 0.0 > >> > >> StructRho = 2.0 > > >> CableTension = OmegaY*OmegaY*StructRho > >> BendingStiff = 0.0 > > >> FictDamp = 1.0 > > >> FictMass = 1.5 > >> > >> </PARAMETERS> > >> > >> <VARIABLES> > >> <V ID="0"> u </V> > >> <V ID="1"> v </V> > >> <V ID="2"> w </V> > >> <V ID="3"> p </V> > >> </VARIABLES> > >> > >> <BOUNDARYREGIONS> > >> C[5]  > >> C[3]  > >> C[4]  > >> C[2]  > >> C[1]  > >> </BOUNDARYREGIONS> > >> > >> <BOUNDARYCONDITIONS> > >> <REGION REF="0"> > >> <D VAR="u" USERDEFINEDTYPE="MovingBody" VALUE="0" /> > >> <D VAR="v" USERDEFINEDTYPE="MovingBody" VALUE="0" /> > >> <D VAR="w" VALUE="0" /> > >> <N VAR="p" USERDEFINEDTYPE="H" VALUE="0" /> > >> </REGION> > >> <REGION REF="1"> > >> > >> > >> > >> > >> </REGION> > >> <REGION REF="2"> > >> > >> > >> > >> > >> </REGION> > >> <REGION REF="3"> > >> <N VAR="u" VALUE="0" /> > >> <N VAR="v" VALUE="0" /> > >> <N VAR="w" VALUE="0" /> > >> <D VAR="p" VALUE="0" /> > >> </REGION> > >> <REGION REF="4"> > >> <D VAR="u" VALUE="1" /> > >> <D VAR="v" VALUE="0" /> > >> <D VAR="w" VALUE="0" /> > >> <N VAR="p" USERDEFINEDTYPE="H" VALUE="0" /> > >> </REGION> > >> </BOUNDARYCONDITIONS> > >> > >> <FUNCTION NAME="InitialConditions"> > >> <E VAR="u" VALUE="0" /> > >> <E VAR="v" VALUE="0" /> > >> <E VAR="w" VALUE="0" /> > >> <E VAR="p" VALUE="0" /> > >> </FUNCTION> > >> > >> > >> <FUNCTION NAME="displacements"> > >> <E VAR="x" VALUE="0.0" /> > >> <E VAR="y" VALUE="A*cos(omega*t)*cos(2*PI*z/LZ)" /> > >> </FUNCTION> > >> <FUNCTION NAME="velocities"> > >> <E VAR="x" VALUE="0.0" /> > >> <E VAR="y" VALUE="-1.0*omega*A*sin(omega*t)*cos(2*PI*z/LZ)" > /> > >> </FUNCTION> > >> <FUNCTION NAME="Mapping"> > >> <E VAR="x" VALUE="x" /> > >> <E VAR="y" VALUE="y+A*cos(omega*t)*cos(2*PI*z/LZ)" /> > >> </FUNCTION> > >> <FUNCTION NAME="MappingVel"> > >> <E VAR="vx" VALUE="0.0" /> > >> <E VAR="vy" VALUE="-1.0*omega*A*sin(omega*t)*cos(2*PI*z/LZ)" > >> /> > >> </FUNCTION> > >> <FUNCTION NAME="accelerations"> > >> <E VAR="x" VALUE="0.0" /> > >> <E VAR="y" > >> VALUE="-1.0*omega*omega*A*cos(omega*t)*cos(2*PI*z/LZ)" /> > >> </FUNCTION> > >> > >> </CONDITIONS> > >> > >> <MAPPING TYPE="XYofZ"> > >> <COORDS>Mapping</COORDS> > >> <VEL>MappingVel</VEL> > >> <TIMEDEPENDENT>True</TIMEDEPENDENT> > >> </MAPPING> > >> > >> <FORCING> > >> <FORCE TYPE="MovingBody"> > >> <DISPLACEMENTS> displacements </DISPLACEMENTS> > >> <VELOCITIES> velocities </VELOCITIES> > >> <ACCELERATIONS> accelerations </ACCELERATIONS> > >> <PARAM NAME="OutputFile">TensionedCable</PARAM> > >> <PARAM NAME="OutputFrequency">25</PARAM> > >> <PARAM NAME="Boundary"> B[0] </PARAM> > >> </FORCE> > >> </FORCING> > >> > >> > **************************************************************************************** > >> Best Wishes, > >> Zhicheng Wang > >> _______________________________________________ > >> Nektar-users mailing list > >> Nektar-users(a)imperial.ac.uk > >> https://mailman.ic.ac.uk/mailman/listinfo/nektar-users > >> > >> > >> Spencer Sherwin FREng, FRAeS > >> Head of Aerodynamics Section, > >> Director of Research Computing Service, > >> Professor of Computational Fluid Mechanics, > >> Department of Aeronautics, > >> s.sherwin(a)imperial.ac.uk South > >> Kensington Campus, > >> Phone: +44 (0)20 7594 5052 Imperial College > >> London, > >> Fax: +44 (0)20 7594 1974 London, SW7 > 2AZ, > >> UK > >> http://www.imperial.ac.uk/people/s.sherwin/ > >> > >> > >

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Re: [Nektar-users] VIV flow past a cylinder
by Wang, Zhicheng 26 Feb '20

26 Feb '20

Hi Mohsen and Yan, thanks for your reply. Please find the amplitude and lift coefficient are attached below. The lift coef looks reasonable. Personally, I have done tons of similar simulations using the predecessor SEM code Nektar, usually, VIV simulation is not sensitive to quadrature points, aliasing error.... I will look at the code. Please let me know if you get a chance to find out the mistakes in my parameter file. On Wed, Feb 26, 2020 at 7:31 AM ybao <ybao(a)sjtu.edu.cn> wrote: > Hi Zhicheng, > > May you show me the time history of the cylinder vibration and lift > coefficient for us? in NEKTAR++, the Euler beam model was employed to > describe the vibration of the structure, so you need to check whether or > not the values of tension, structure stiffness and bending stiffness are > correct. recently Vijay, a graduate student in my group, have run 2D > simulations and got correct results. > > Hi Vijay, can you have a look on the xml from Zhicheng? many thanks! > > Cheers, > Yan > > On 26 Feb 2020, at 05:09, Wang, Zhicheng <zhicheng_wang(a)brown.edu> wrote: > > Thank you Spencer. I will wait for Yan Bao or Mohsen's response. There is > no numerical instability issue for now, but thank you for the suggestion. > > On Tue, Feb 25, 2020 at 3:47 PM Sherwin, Spencer J < > s.sherwin(a)imperial.ac.uk> wrote: > >> HI Zhicheng, >> >> I am forwarding your request to Yan Bao who is probably the most >> experienced in this setup. Not sure if Yan is using the Nektar++ users list >> however. >> >> I would be inclined to use the SpectralVanishingViscosity with DGKernel >> and Dealisasing if you get any flow instability issues. >> >> Cheers, >> Spencer >> >> PS Mohsen might be able to help too. >> >> On 25 Feb 2020, at 15:05, Wang, Zhicheng <zhicheng_wang(a)brown.edu> wrote: >> >> This email from zhicheng_wang(a)brown.edu 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 nektar++ users, >> I wonder if there is anyone could check my simulation parameters for the >> simulation of 2D vortex induced vibration (VIV) of flow past a cylinder >> that is allowed to move in crossflow direction ? Here the cylinder is >> rigidly mounted with a natural frequency f=0.17, mass per unit length =2.0, >> Re=100. For this particular case, the vibration amplitude is expected to >> be around 0.5D, but the simulation gave me 0.05D. So I think I must have >> made some mistakes somewhere in the parameter file. The parameter file I >> used is posted below. >> >> ****************************************************************** >> <EXPANSIONS> >> <E COMPOSITE="C[0]" BASISTYPE="Modified_A, Modified_A" >> NUMMODES="3,3" POINTSTYPE="GaussLobattoLegendre, >> GaussLobattoLegendre" >> NUMPOINTS="5,5" FIELDS="u,v,w,p" /> >> </EXPANSIONS> >> >> <CONDITIONS> >> <SOLVERINFO> >> >> >> >> >> >> >> >> >> >> >> >> >> </SOLVERINFO> >> >> <PARAMETERS> >> TimeStep = 0.005 >> FinalTime = 1000 >> NumSteps = FinalTime/TimeStep >> IO_CheckSteps = 2000 >> IO_InfoSteps = 25 >> IO_CFLSteps = 25 >> Re = 100 >> >> Kinvis = 1/Re >> >> HomModesZ = 2 >> LZ = 0.01 >> >> FreqY = 0.17 >> >> OmegaY = 2.0*PI*FreqY >> >> StructStiff = 0.0 >> >> StructRho = 2.0 >> CableTension = OmegaY*OmegaY*StructRho >> BendingStiff = 0.0 >> FictDamp = 1.0 >> FictMass = 1.5 >> >> </PARAMETERS> >> >> <VARIABLES> >> <V ID="0"> u </V> >> <V ID="1"> v </V> >> <V ID="2"> w </V> >> <V ID="3"> p </V> >> </VARIABLES> >> >> <BOUNDARYREGIONS> >> C[5]  >> C[3]  >> C[4]  >> C[2]  >> C[1]  >> </BOUNDARYREGIONS> >> >> <BOUNDARYCONDITIONS> >> <REGION REF="0"> >> <D VAR="u" USERDEFINEDTYPE="MovingBody" VALUE="0" /> >> <D VAR="v" USERDEFINEDTYPE="MovingBody" VALUE="0" /> >> <D VAR="w" VALUE="0" /> >> <N VAR="p" USERDEFINEDTYPE="H" VALUE="0" /> >> </REGION> >> <REGION REF="1"> >> >> >> >> >> </REGION> >> <REGION REF="2"> >> >> >> >> >> </REGION> >> <REGION REF="3"> >> <N VAR="u" VALUE="0" /> >> <N VAR="v" VALUE="0" /> >> <N VAR="w" VALUE="0" /> >> <D VAR="p" VALUE="0" /> >> </REGION> >> <REGION REF="4"> >> <D VAR="u" VALUE="1" /> >> <D VAR="v" VALUE="0" /> >> <D VAR="w" VALUE="0" /> >> <N VAR="p" USERDEFINEDTYPE="H" VALUE="0" /> >> </REGION> >> </BOUNDARYCONDITIONS> >> >> <FUNCTION NAME="InitialConditions"> >> <E VAR="u" VALUE="0" /> >> <E VAR="v" VALUE="0" /> >> <E VAR="w" VALUE="0" /> >> <E VAR="p" VALUE="0" /> >> </FUNCTION> >> >> >> <FUNCTION NAME="displacements"> >> <E VAR="x" VALUE="0.0" /> >> <E VAR="y" VALUE="A*cos(omega*t)*cos(2*PI*z/LZ)" /> >> </FUNCTION> >> <FUNCTION NAME="velocities"> >> <E VAR="x" VALUE="0.0" /> >> <E VAR="y" VALUE="-1.0*omega*A*sin(omega*t)*cos(2*PI*z/LZ)" /> >> </FUNCTION> >> <FUNCTION NAME="Mapping"> >> <E VAR="x" VALUE="x" /> >> <E VAR="y" VALUE="y+A*cos(omega*t)*cos(2*PI*z/LZ)" /> >> </FUNCTION> >> <FUNCTION NAME="MappingVel"> >> <E VAR="vx" VALUE="0.0" /> >> <E VAR="vy" VALUE="-1.0*omega*A*sin(omega*t)*cos(2*PI*z/LZ)" >> /> >> </FUNCTION> >> <FUNCTION NAME="accelerations"> >> <E VAR="x" VALUE="0.0" /> >> <E VAR="y" >> VALUE="-1.0*omega*omega*A*cos(omega*t)*cos(2*PI*z/LZ)" /> >> </FUNCTION> >> >> </CONDITIONS> >> >> <MAPPING TYPE="XYofZ"> >> <COORDS>Mapping</COORDS> >> <VEL>MappingVel</VEL> >> <TIMEDEPENDENT>True</TIMEDEPENDENT> >> </MAPPING> >> >> <FORCING> >> <FORCE TYPE="MovingBody"> >> <DISPLACEMENTS> displacements </DISPLACEMENTS> >> <VELOCITIES> velocities </VELOCITIES> >> <ACCELERATIONS> accelerations </ACCELERATIONS> >> <PARAM NAME="OutputFile">TensionedCable</PARAM> >> <PARAM NAME="OutputFrequency">25</PARAM> >> <PARAM NAME="Boundary"> B[0] </PARAM> >> </FORCE> >> </FORCING> >> >> **************************************************************************************** >> Best Wishes, >> Zhicheng Wang >> _______________________________________________ >> Nektar-users mailing list >> Nektar-users(a)imperial.ac.uk >> https://mailman.ic.ac.uk/mailman/listinfo/nektar-users >> >> >> Spencer Sherwin FREng, FRAeS >> Head of Aerodynamics Section, >> Director of Research Computing Service, >> Professor of Computational Fluid Mechanics, >> Department of Aeronautics, >> s.sherwin(a)imperial.ac.uk South >> Kensington Campus, >> Phone: +44 (0)20 7594 5052 Imperial College >> London, >> Fax: +44 (0)20 7594 1974 London, SW7 2AZ, >> UK >> http://www.imperial.ac.uk/people/s.sherwin/ >> >> >

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Re: [Nektar-users] NekMesh Error in Converting the MSH in Nektar++ format
by Silvia Ceccacci (HDR) 26 Feb '20

26 Feb '20

Hi Dave, Thank you for your reply. I’m using the latest one (v5.0.0). Many thanks, Silvia Get Outlook for iOS<https://aka.ms/o0ukef> ________________________________ From: Moxey, David <D.Moxey(a)exeter.ac.uk> Sent: Wednesday, February 26, 2020 8:55:46 PM To: Silvia Ceccacci (HDR) <silvia.ceccacci(a)hdr.mq.edu.au> Cc: nektar-users(a)imperial.ac.uk <nektar-users(a)imperial.ac.uk> Subject: Re: [Nektar-users] NekMesh Error in Converting the MSH in Nektar++ format Hi Silvia, Could I ask what version of Nektar++ you're using? The MSH format changed somewhat recently, so the reader for this is in our latest release (v5.0.0). Many thanks, Dave > On 26 Feb 2020, at 04:34, Silvia Ceccacci (HDR) <silvia.ceccacci(a)hdr.mq.edu.au> wrote: > > This email from silvia.ceccacci(a)hdr.mq.edu.au 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 to disable email stamping for this address. > > Dear all, > > This is Silvia Ceccacci from Macquarie University, Sydney. I am a new PhD student in Mathematics and I have just started to use Nektar++ to perform 3D incompressible N-S simulations. > > I am exporting a mesh from gmsh and I am trying to simulate a flow around a sphere. So I would like to generate the 3D mesh within the main domain with the sphere taken out (see sphere_2.geo). I managed to generate the .msh file (see sphere_2.msh), using the command line > > gmsh -3 -order 3 sphere_2.geo > > but now I get an error (see error.png) when I issue > > NekMesh sphere_2.msh sphere_2.xml > > I am not sure what the error means and/or what am I doing wrong? Could you help me with this, please? > > Any little help or suggestion would be greatly appreciated. > > Thank you in advance. > > Kind regards, > Silvia > > > <sphere.zip>_______________________________________________ > Nektar-users mailing list > Nektar-users(a)imperial.ac.uk > https://mailman.ic.ac.uk/mailman/listinfo/nektar-users<https://mailman.ic.ac.uk/mailman/listinfo/nektar-users> -- Dr David Moxey, PhD MMath MIMA FHEA Senior Lecturer in Engineering d.moxey(a)exeter.ac.uk | tel: 01392 724764 | web: davidmoxey.uk Room 1.24, Hope Hall, University of Exeter, Exeter, EX4 4PL, UK.

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NekMesh Error in Converting the MSH in Nektar++ format
by Silvia Ceccacci (HDR) 26 Feb '20

26 Feb '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, This is Silvia Ceccacci from Macquarie University, Sydney. I am a new PhD student in Mathematics and I have just started to use Nektar++ to perform 3D incompressible N-S simulations. I am exporting a mesh from gmsh and I am trying to simulate a flow around a sphere. So I would like to generate the 3D mesh within the main domain with the sphere taken out (see sphere_2.geo). I managed to generate the .msh file (see sphere_2.msh), using the command line gmsh -3 -order 3 sphere_2.geo but now I get an error (see error.png) when I issue NekMesh sphere_2.msh sphere_2.xml I am not sure what the error means and/or what am I doing wrong? Could you help me with this, please? Any little help or suggestion would be greatly appreciated. Thank you in advance. Kind regards, Silvia

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VIV flow past a cylinder
by Wang, Zhicheng 25 Feb '20

25 Feb '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 nektar++ users, I wonder if there is anyone could check my simulation parameters for the simulation of 2D vortex induced vibration (VIV) of flow past a cylinder that is allowed to move in crossflow direction ? Here the cylinder is rigidly mounted with a natural frequency f=0.17, mass per unit length =2.0, Re=100. For this particular case, the vibration amplitude is expected to be around 0.5D, but the simulation gave me 0.05D. So I think I must have made some mistakes somewhere in the parameter file. The parameter file I used is posted below. ****************************************************************** <EXPANSIONS> <E COMPOSITE="C[0]" BASISTYPE="Modified_A, Modified_A" NUMMODES="3,3" POINTSTYPE="GaussLobattoLegendre, GaussLobattoLegendre" NUMPOINTS="5,5" FIELDS="u,v,w,p" /> </EXPANSIONS> <CONDITIONS> <SOLVERINFO> </SOLVERINFO> <PARAMETERS> TimeStep = 0.005 FinalTime = 1000 NumSteps = FinalTime/TimeStep IO_CheckSteps = 2000 IO_InfoSteps = 25 IO_CFLSteps = 25 Re = 100 Kinvis = 1/Re HomModesZ = 2 LZ = 0.01 FreqY = 0.17 OmegaY = 2.0*PI*FreqY StructStiff = 0.0 StructRho = 2.0 CableTension = OmegaY*OmegaY*StructRho BendingStiff = 0.0 FictDamp = 1.0 FictMass = 1.5 </PARAMETERS> <VARIABLES> <V ID="0"> u </V> <V ID="1"> v </V> <V ID="2"> w </V> <V ID="3"> p </V> </VARIABLES> <BOUNDARYREGIONS> C[5]  C[3]  C[4]  C[2]  C[1]  </BOUNDARYREGIONS> <BOUNDARYCONDITIONS> <REGION REF="0"> <D VAR="u" USERDEFINEDTYPE="MovingBody" VALUE="0" /> <D VAR="v" USERDEFINEDTYPE="MovingBody" VALUE="0" /> <D VAR="w" VALUE="0" /> <N VAR="p" USERDEFINEDTYPE="H" VALUE="0" /> </REGION> <REGION REF="1"> </REGION> <REGION REF="2"> </REGION> <REGION REF="3"> <N VAR="u" VALUE="0" /> <N VAR="v" VALUE="0" /> <N VAR="w" VALUE="0" /> <D VAR="p" VALUE="0" /> </REGION> <REGION REF="4"> <D VAR="u" VALUE="1" /> <D VAR="v" VALUE="0" /> <D VAR="w" VALUE="0" /> <N VAR="p" USERDEFINEDTYPE="H" VALUE="0" /> </REGION> </BOUNDARYCONDITIONS> <FUNCTION NAME="InitialConditions"> <E VAR="u" VALUE="0" /> <E VAR="v" VALUE="0" /> <E VAR="w" VALUE="0" /> <E VAR="p" VALUE="0" /> </FUNCTION> <FUNCTION NAME="displacements"> <E VAR="x" VALUE="0.0" /> <E VAR="y" VALUE="A*cos(omega*t)*cos(2*PI*z/LZ)" /> </FUNCTION> <FUNCTION NAME="velocities"> <E VAR="x" VALUE="0.0" /> <E VAR="y" VALUE="-1.0*omega*A*sin(omega*t)*cos(2*PI*z/LZ)" /> </FUNCTION> <FUNCTION NAME="Mapping"> <E VAR="x" VALUE="x" /> <E VAR="y" VALUE="y+A*cos(omega*t)*cos(2*PI*z/LZ)" /> </FUNCTION> <FUNCTION NAME="MappingVel"> <E VAR="vx" VALUE="0.0" /> <E VAR="vy" VALUE="-1.0*omega*A*sin(omega*t)*cos(2*PI*z/LZ)" /> </FUNCTION> <FUNCTION NAME="accelerations"> <E VAR="x" VALUE="0.0" /> <E VAR="y" VALUE="-1.0*omega*omega*A*cos(omega*t)*cos(2*PI*z/LZ)" /> </FUNCTION> </CONDITIONS> <MAPPING TYPE="XYofZ"> <COORDS>Mapping</COORDS> <VEL>MappingVel</VEL> <TIMEDEPENDENT>True</TIMEDEPENDENT> </MAPPING> <FORCING> <FORCE TYPE="MovingBody"> <DISPLACEMENTS> displacements </DISPLACEMENTS> <VELOCITIES> velocities </VELOCITIES> <ACCELERATIONS> accelerations </ACCELERATIONS> <PARAM NAME="OutputFile">TensionedCable</PARAM> <PARAM NAME="OutputFrequency">25</PARAM> <PARAM NAME="Boundary"> B[0] </PARAM> </FORCE> </FORCING> **************************************************************************************** Best Wishes, Zhicheng Wang

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Question about Stream function module for 2D, Incompressible Flow
by Seyedi, Hadi 24 Feb '20

24 Feb '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. ******************* Hello all, This is Hadi Seyedi from Michigan State University. I am a PhD student at ME department and I am using NEKTAR++ to perform my 2D incompressible N-S simulations. When I want to use the Stream function module in FiledConvert, I am getting the below error. I could use the other modules easily, but this one (streamfunction module) doesn't work for my cases. Would you please help me in this regard? Thank You in advance, Hadi Error: Fatal : Level 0 assertion violation Variable index out of range. terminate called after throwing an instance of 'Nektar::ErrorUtil::NekError' what(): Level 0 assertion violation Variable index out of range. [Hadi-PC:05963] *** Process received signal *** [Hadi-PC:05963] Signal: Aborted (6) [Hadi-PC:05963] Signal code: (-6) [Hadi-PC:05963] [ 0] /lib/x86_64-linux-gnu/libpthread.so.0(+0x12890)[0x7f86a3e80890] [Hadi-PC:05963] [ 1] /lib/x86_64-linux-gnu/libc.so.6(gsignal+0xc7)[0x7f86a3abbe97] [Hadi-PC:05963] [ 2] /lib/x86_64-linux-gnu/libc.so.6(abort+0x141)[0x7f86a3abd801] [Hadi-PC:05963] [ 3] /usr/lib/x86_64-linux-gnu/libstdc++.so.6(+0x8c957)[0x7f86a46cf957] [Hadi-PC:05963] [ 4] /usr/lib/x86_64-linux-gnu/libstdc++.so.6(+0x92ab6)[0x7f86a46d5ab6] [Hadi-PC:05963] [ 5] /usr/lib/x86_64-linux-gnu/libstdc++.so.6(+0x92af1)[0x7f86a46d5af1] [Hadi-PC:05963] [ 6] /usr/lib/x86_64-linux-gnu/libstdc++.so.6(+0x92d24)[0x7f86a46d5d24] [Hadi-PC:05963] [ 7] /home/hadi/NEKTAR/nektar++-5.0.0/build/dist/lib64/libLibUtilities.so.5.0.0(+0x1b8c32)[0x7f86a5516c32] [Hadi-PC:05963] [ 8] /home/hadi/NEKTAR/nektar++-5.0.0/build/dist/lib64/libLibUtilities.so.5.0.0(+0x1b9058)[0x7f86a5517058] [Hadi-PC:05963] [ 9] /home/hadi/NEKTAR/nektar++-5.0.0/build/dist/lib64/libFieldUtils.so.5.0.0(_ZN6Nektar10FieldUtils5Field17SetUpFirstExpListEib+0xec5)[0x7f86a5f8f305] [Hadi-PC:05963] [10] /home/hadi/NEKTAR/nektar++-5.0.0/build/dist/lib64/libFieldUtils.so.5.0.0(_ZN6Nektar10FieldUtils16ProcessCreateExp7ProcessERN5boost15program_options13variables_mapE+0x43d)[0x7f86a5fb61cd] [Hadi-PC:05963] [11] FieldConvert(_Z9RunModuleSt10shared_ptrIN6Nektar10FieldUtils6ModuleEERN5boost15program_options13variables_mapEb+0x3f)[0x55f8f55093af] [Hadi-PC:05963] [12] FieldConvert(main+0x172c)[0x55f8f550587c] [Hadi-PC:05963] [13] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe7)[0x7f86a3a9eb97] [Hadi-PC:05963] [14] FieldConvert(_start+0x2a)[0x55f8f5508d3a] [Hadi-PC:05963] *** End of error message *** Aborted (core dumped)

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Regarding installing the Nektar++
by pavan yadav 12 Feb '20

12 Feb '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 Sir, I am struggling with installation of Nektar++ on ubuntu 16.04. Can you please suggest a way to install it? Regards, Pavan

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Installing Nektar++ in Windows 10
by m_moayeri＠sbu.ac.ir 11 Feb '20

11 Feb '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 a PhD candidate of scientific computing at Shahid Beheshti university, Iran. I am trying to install Nektar++ in Windows. I follow up the instructions in user guide, but I encounter with the following errors when I try to do 11th steps of installing Nektar++: "C:\University\PhD\Nektar++\nektar++-5.0.0\builds\INSTALL.vcxproj" (default target) (1) -> "C:\University\PhD\Nektar++\nektar++-5.0.0\builds\ALL_BUILD.vcxproj" (default target) (3) -> "C:\University\PhD\Nektar++\nektar++-5.0.0\builds\boost.vcxproj" (default target) (8) -> (CustomBuild target) -> collect2.exe : error : ld returned 1 exit status [C:\University\PhD\Nektar++\nektar++-5.0.0\builds\boost.vcxpr oj] collect2.exe : error : ld returned 1 exit status [C:\University\PhD\Nektar++\nektar++-5.0.0\builds\boost.vcxpr oj] collect2.exe : error : ld returned 1 exit status [C:\University\PhD\Nektar++\nektar++-5.0.0\builds\boost.vcxpr oj] collect2.exe : error : ld returned 1 exit status [C:\University\PhD\Nektar++\nektar++-5.0.0\builds\boost.vcxpr oj] Does any one know what are the error related to and help me? Best regards, Mahdi

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