Re: [Nektar-users] Source terms and mesh generation
Dear users, Hi Kilian, sorry I have to ask another question and I hope you or somebody else can give me an answer. Actually I tried to use an analytical source term like this: <FUNCTION NAME="Source"> <E VAR="S" VALUE="0.5*exp((-0.34657*(((x-2)^2)+((y-0)^2))))*sin(2*3.14/30*t)" /> </FUNCTION> in the acoustic perturbation equation. I tried other kind of source terms too. Besides I am using a base flow as a result from an incompressible flow simulation. The APE reads them right, but it seems the solver does not read the source term. The results of field of p,u,v,rho are constant in time and do not change. Can somebody explain that? Best regards Fabian Von: Fabian Selbach [fabian.selbach@student.uni-siegen.de] Gesendet: Donnerstag, 9. Februar 2017 09:36 An: Kilian Lackhove Betreff: Re: [Nektar-users] Source terms and mesh generation Thanks Kilian, I thought so, but want to ask about it. Best regards Fabian Selbach
Am 09.02.2017 um 08:45 schrieb Kilian Lackhove <lackhove@ekt.tu-darmstadt.de>:
Hi Fabian,
there are a number of different source term formultations people use for the APE, so our implementation is "source-term agnostic" in the way that you can specify whatever RHS you want.
I dont think we have a tool to compute derived fields (e.g. acoustic source terms) from other fields (e.g. velocity, pressure, density ...) right now. So you could either convert the fld files from the CompressibleFlowSolver to pts, read those with python, matlab, etc., compute the source term, store it as pts again and feed this into the APESolver. This is what other people do. The alternative would be writing a FieldConvert module to take care of this.
Cheers,
Kilian
Am Dienstag, 7. Februar 2017, 12:13:30 CET schrieb Selbach, Fabian:
Dear users,
can somebody send me an example of an APE-Simulation by a source from file of another simulation? Is it actually possible to do something like that in Nektar++?
To take the base flow from a simulation is easy, but to get the acoustical source term is quit difficult and actually not possible, I think. Am I right?
Best regards
Fabian ________________________________ Von: Selbach, Fabian Gesendet: Freitag, 27. Januar 2017 16:14 An: nektar-users@imperial.ac.uk Betreff: Source terms and mesh generation
Dear Users,
which kind of mesh generator do you recommend to get a good mesh for an airfoil simulation? Actually I am using Gmsh.
My next question deals with the CompressibleFlowSolver in Nektar++. Is there a possibility to get acoustical source terms during a simulation with its?
Best regards
Fabian
-- Kilian Lackhove, M.Sc. Fachgebiet für Energie- und Kraftwerkstechnik L1|08 114 Technische Universität Darmstadt Jovanka-Bontschits-Straße 2 D-64287 Darmstadt Germany
Tel.: +49 6151 16 - 28915 Fax: +49 6151 16 - 6555 e-mail: lackhove@ekt.tu-darmstadt.de
Hi Fabian, which Nektar++ version are you using? The way source terms are handled by the APSolver changed recently. Now, the generic forcings can be used and source terms can be specified for each equation separately. The "APE_2DPulseAdv_WeakDG_MODIFIED.xml" case inside the APESolver/Tests directory makes use of this functionality. Regarding the baseflow fields, i suspect you missed the TIMEDEPENDENT="1" parameter or the formatting string of the filename in the Baseflow function, e.g.: <FUNCTION NAME="Baseflow"> <F VAR="u0,v0" TIMEDEPENDENT="1" FILE="APE_2DPulseInterp_baseflow_ %14.8E.pts"/> <E VAR="p0" VALUE="Pinfinity"/> <E VAR="rho0" VALUE="Rho0"/> </FUNCTION> an example can again be found in the APESolver/Tests/ APE_2DPulseInterp_WeakDG_MODIFIED.xml Cheers, Kilian Am Montag, 13. Februar 2017, 12:26:33 CET schrieb Selbach, Fabian:
Dear users, Hi Kilian,
sorry I have to ask another question and I hope you or somebody else can give me an answer.
Actually I tried to use an analytical source term like this:
<FUNCTION NAME="Source"> <E VAR="S" VALUE="0.5*exp((-0.34657*(((x-2)^2)+((y-0)^2))))*sin(2*3.14/30*t)" /> </FUNCTION>
in the acoustic perturbation equation. I tried other kind of source terms too. Besides I am using a base flow as a result from an incompressible flow simulation. The APE reads them right, but it seems the solver does not read the source term. The results of field of p,u,v,rho are constant in time and do not change.
Can somebody explain that?
Best regards
Fabian
Von: Fabian Selbach [fabian.selbach@student.uni-siegen.de] Gesendet: Donnerstag, 9. Februar 2017 09:36 An: Kilian Lackhove Betreff: Re: [Nektar-users] Source terms and mesh generation
Thanks Kilian,
I thought so, but want to ask about it.
Best regards
Fabian Selbach
Am 09.02.2017 um 08:45 schrieb Kilian Lackhove <lackhove@ekt.tu-darmstadt.de>:
Hi Fabian,
there are a number of different source term formultations people use for the APE, so our implementation is "source-term agnostic" in the way that you can specify whatever RHS you want.
I dont think we have a tool to compute derived fields (e.g. acoustic source terms) from other fields (e.g. velocity, pressure, density ...) right now. So you could either convert the fld files from the CompressibleFlowSolver to pts, read those with python, matlab, etc., compute the source term, store it as pts again and feed this into the APESolver. This is what other people do. The alternative would be writing a FieldConvert module to take care of this.
Cheers,
Kilian
Am Dienstag, 7. Februar 2017, 12:13:30 CET schrieb Selbach, Fabian:
Dear users,
can somebody send me an example of an APE-Simulation by a source from file of another simulation? Is it actually possible to do something like that in Nektar++?
To take the base flow from a simulation is easy, but to get the acoustical source term is quit difficult and actually not possible, I think. Am I right?
Best regards
Fabian ________________________________ Von: Selbach, Fabian Gesendet: Freitag, 27. Januar 2017 16:14 An: nektar-users@imperial.ac.uk Betreff: Source terms and mesh generation
Dear Users,
which kind of mesh generator do you recommend to get a good mesh for an airfoil simulation? Actually I am using Gmsh.
My next question deals with the CompressibleFlowSolver in Nektar++. Is there a possibility to get acoustical source terms during a simulation with its?
Best regards
Fabian
-- Kilian Lackhove, M.Sc. Fachgebiet für Energie- und Kraftwerkstechnik L1|08 114 Technische Universität Darmstadt Jovanka-Bontschits-Straße 2 D-64287 Darmstadt Germany
Tel.: +49 6151 16 - 28915 Fax: +49 6151 16 - 6555 e-mail: lackhove@ekt.tu-darmstadt.de
-- Kilian Lackhove, M.Sc. Fachgebiet für Energie- und Kraftwerkstechnik L1|08 114 Technische Universität Darmstadt Jovanka-Bontschits-Straße 2 D-64287 Darmstadt Germany Tel.: +49 6151 16 - 28915 Fax: +49 6151 16 - 6555 e-mail: lackhove@ekt.tu-darmstadt.de
Hi Kilian, I am using the repository version (4.4.0). I thought that the APE just defines the source term qc on the RHS of the equations as described in the user guide and proposed by Ewert and Schröder. So is there a possibility to define the variable qc directly in Nektar++? When I define p,u,v in the way you described, I am just doing some kind of forcing of the variables, but I am not defining the acoustical source term in the direct way. Or do I define the variables and it calculate qc internal? I do not think so. How is the connection between this? Thanks in advance. Best regards Fabian ________________________________________ Von: Kilian Lackhove [lackhove@ekt.tu-darmstadt.de] Gesendet: Mittwoch, 15. Februar 2017 10:08 An: Selbach, Fabian Cc: nektar-users@imperial.ac.uk Betreff: Re: AW: [Nektar-users] Source terms and mesh generation Hi Fabian, which Nektar++ version are you using? The way source terms are handled by the APSolver changed recently. Now, the generic forcings can be used and source terms can be specified for each equation separately. The "APE_2DPulseAdv_WeakDG_MODIFIED.xml" case inside the APESolver/Tests directory makes use of this functionality. Regarding the baseflow fields, i suspect you missed the TIMEDEPENDENT="1" parameter or the formatting string of the filename in the Baseflow function, e.g.: <FUNCTION NAME="Baseflow"> <F VAR="u0,v0" TIMEDEPENDENT="1" FILE="APE_2DPulseInterp_baseflow_ %14.8E.pts"/> <E VAR="p0" VALUE="Pinfinity"/> <E VAR="rho0" VALUE="Rho0"/> </FUNCTION> an example can again be found in the APESolver/Tests/ APE_2DPulseInterp_WeakDG_MODIFIED.xml Cheers, Kilian Am Montag, 13. Februar 2017, 12:26:33 CET schrieb Selbach, Fabian:
Dear users, Hi Kilian,
sorry I have to ask another question and I hope you or somebody else can give me an answer.
Actually I tried to use an analytical source term like this:
<FUNCTION NAME="Source"> <E VAR="S" VALUE="0.5*exp((-0.34657*(((x-2)^2)+((y-0)^2))))*sin(2*3.14/30*t)" /> </FUNCTION>
in the acoustic perturbation equation. I tried other kind of source terms too. Besides I am using a base flow as a result from an incompressible flow simulation. The APE reads them right, but it seems the solver does not read the source term. The results of field of p,u,v,rho are constant in time and do not change.
Can somebody explain that?
Best regards
Fabian
Von: Fabian Selbach [fabian.selbach@student.uni-siegen.de] Gesendet: Donnerstag, 9. Februar 2017 09:36 An: Kilian Lackhove Betreff: Re: [Nektar-users] Source terms and mesh generation
Thanks Kilian,
I thought so, but want to ask about it.
Best regards
Fabian Selbach
Am 09.02.2017 um 08:45 schrieb Kilian Lackhove <lackhove@ekt.tu-darmstadt.de>:
Hi Fabian,
there are a number of different source term formultations people use for the APE, so our implementation is "source-term agnostic" in the way that you can specify whatever RHS you want.
I dont think we have a tool to compute derived fields (e.g. acoustic source terms) from other fields (e.g. velocity, pressure, density ...) right now. So you could either convert the fld files from the CompressibleFlowSolver to pts, read those with python, matlab, etc., compute the source term, store it as pts again and feed this into the APESolver. This is what other people do. The alternative would be writing a FieldConvert module to take care of this.
Cheers,
Kilian
Am Dienstag, 7. Februar 2017, 12:13:30 CET schrieb Selbach, Fabian:
Dear users,
can somebody send me an example of an APE-Simulation by a source from file of another simulation? Is it actually possible to do something like that in Nektar++?
To take the base flow from a simulation is easy, but to get the acoustical source term is quit difficult and actually not possible, I think. Am I right?
Best regards
Fabian ________________________________ Von: Selbach, Fabian Gesendet: Freitag, 27. Januar 2017 16:14 An: nektar-users@imperial.ac.uk Betreff: Source terms and mesh generation
Dear Users,
which kind of mesh generator do you recommend to get a good mesh for an airfoil simulation? Actually I am using Gmsh.
My next question deals with the CompressibleFlowSolver in Nektar++. Is there a possibility to get acoustical source terms during a simulation with its?
Best regards
Fabian
-- Kilian Lackhove, M.Sc. Fachgebiet für Energie- und Kraftwerkstechnik L1|08 114 Technische Universität Darmstadt Jovanka-Bontschits-Straße 2 D-64287 Darmstadt Germany
Tel.: +49 6151 16 - 28915 Fax: +49 6151 16 - 6555 e-mail: lackhove@ekt.tu-darmstadt.de
-- Kilian Lackhove, M.Sc. Fachgebiet für Energie- und Kraftwerkstechnik L1|08 114 Technische Universität Darmstadt Jovanka-Bontschits-Straße 2 D-64287 Darmstadt Germany Tel.: +49 6151 16 - 28915 Fax: +49 6151 16 - 6555 e-mail: lackhove@ekt.tu-darmstadt.de
Hi Fabian, the forcings specify the entire RHS, so when using e.g. <CONDITIONS> ... <FUNCTION NAME="Source"> <E VAR="p" VALUE="100 * 2*PI*5E2 * cos(2*PI*5E2 * t) * exp(-32*(x^2+y^2))"/> <E VAR="u" VALUE="0"/> <E VAR="v" VALUE="0"/> </FUNCTION> </CONDITIONS> <FORCING> <FORCE TYPE="Field"> <FIELDFORCE> Source <FIELDFORCE/> </FORCE> </FORCING> the RHS in eq 47 of the original paper [1] is set to: c^2 * q_c = 100 * 2*PI*5E2 * cos(2*PI*5E2 * t) * exp(-32*(x^2+y^2)) and the RHS of eq 48 is zero. So in order use the APE-1 source term formulation, you would have to manually compute c^2 * q_c and q_m, store them in a pts file (e.g. with variable names cqc, qm_0 and qm_1) and then use these files in the APESolver, e.g. with: <CONDITIONS> ... <FUNCTION NAME="Source"> <F VAR="p" TIMEDEPENDENT="1" FILE=RHS_%14.8E.pts:cqc"/> <F VAR="u" TIMEDEPENDENT="1" FILE=RHS_%14.8E.pts:qm_0"/> <F VAR="v" TIMEDEPENDENT="1" FILE=RHS_%14.8E.pts:qm_1"/> </FUNCTION> </CONDITIONS> <FORCING> <FORCE TYPE="Field"> <FIELDFORCE> Source <FIELDFORCE/> </FORCE> </FORCING> The userguide is indeed outdated, sorry. I will update it as soon as i get to it. Cheers, Kilian [1] Ewert, R., & Schröder, W. (2003). Acoustic perturbation equations based on flow decomposition via source filtering. Journal of Computational Physics, 188(2), 365–398. http://doi.org/10.1016/S0021-9991(03)00168-2 Am Mittwoch, 15. Februar 2017, 09:50:03 CET schrieb Selbach, Fabian:
Hi Kilian,
I am using the repository version (4.4.0). I thought that the APE just defines the source term qc on the RHS of the equations as described in the user guide and proposed by Ewert and Schröder. So is there a possibility to define the variable qc directly in Nektar++? When I define p,u,v in the way you described, I am just doing some kind of forcing of the variables, but I am not defining the acoustical source term in the direct way. Or do I define the variables and it calculate qc internal? I do not think so. How is the connection between this?
Thanks in advance.
Best regards
Fabian ________________________________________ Von: Kilian Lackhove [lackhove@ekt.tu-darmstadt.de] Gesendet: Mittwoch, 15. Februar 2017 10:08 An: Selbach, Fabian Cc: nektar-users@imperial.ac.uk Betreff: Re: AW: [Nektar-users] Source terms and mesh generation
Hi Fabian,
which Nektar++ version are you using? The way source terms are handled by the APSolver changed recently. Now, the generic forcings can be used and source terms can be specified for each equation separately. The "APE_2DPulseAdv_WeakDG_MODIFIED.xml" case inside the APESolver/Tests directory makes use of this functionality.
Regarding the baseflow fields, i suspect you missed the TIMEDEPENDENT="1" parameter or the formatting string of the filename in the Baseflow function, e.g.:
<FUNCTION NAME="Baseflow"> <F VAR="u0,v0" TIMEDEPENDENT="1" FILE="APE_2DPulseInterp_baseflow_ %14.8E.pts"/> <E VAR="p0" VALUE="Pinfinity"/> <E VAR="rho0" VALUE="Rho0"/> </FUNCTION>
an example can again be found in the APESolver/Tests/ APE_2DPulseInterp_WeakDG_MODIFIED.xml
Cheers,
Kilian
Am Montag, 13. Februar 2017, 12:26:33 CET schrieb Selbach, Fabian:
Dear users, Hi Kilian,
sorry I have to ask another question and I hope you or somebody else can give me an answer.
Actually I tried to use an analytical source term like this: <FUNCTION NAME="Source">
<E VAR="S"
VALUE="0.5*exp((-0.34657*(((x-2)^2)+((y-0)^2))))*sin(2*3.14/30*t)" /> </FUNCTION>
in the acoustic perturbation equation. I tried other kind of source terms too. Besides I am using a base flow as a result from an incompressible flow simulation. The APE reads them right, but it seems the solver does not read the source term. The results of field of p,u,v,rho are constant in time and do not change.
Can somebody explain that?
Best regards
Fabian
Von: Fabian Selbach [fabian.selbach@student.uni-siegen.de] Gesendet: Donnerstag, 9. Februar 2017 09:36 An: Kilian Lackhove Betreff: Re: [Nektar-users] Source terms and mesh generation
Thanks Kilian,
I thought so, but want to ask about it.
Best regards
Fabian Selbach
Am 09.02.2017 um 08:45 schrieb Kilian Lackhove <lackhove@ekt.tu-darmstadt.de>:
Hi Fabian,
there are a number of different source term formultations people use for the APE, so our implementation is "source-term agnostic" in the way that you can specify whatever RHS you want.
I dont think we have a tool to compute derived fields (e.g. acoustic source terms) from other fields (e.g. velocity, pressure, density ...) right now. So you could either convert the fld files from the CompressibleFlowSolver to pts, read those with python, matlab, etc., compute the source term, store it as pts again and feed this into the APESolver. This is what other people do. The alternative would be writing a FieldConvert module to take care of this.
Cheers,
Kilian
Am Dienstag, 7. Februar 2017, 12:13:30 CET schrieb Selbach, Fabian:
Dear users,
can somebody send me an example of an APE-Simulation by a source from file of another simulation? Is it actually possible to do something like that in Nektar++?
To take the base flow from a simulation is easy, but to get the acoustical source term is quit difficult and actually not possible, I think. Am I right?
Best regards
Fabian ________________________________ Von: Selbach, Fabian Gesendet: Freitag, 27. Januar 2017 16:14 An: nektar-users@imperial.ac.uk Betreff: Source terms and mesh generation
Dear Users,
which kind of mesh generator do you recommend to get a good mesh for an airfoil simulation? Actually I am using Gmsh.
My next question deals with the CompressibleFlowSolver in Nektar++. Is there a possibility to get acoustical source terms during a simulation with its?
Best regards
Fabian
-- Kilian Lackhove, M.Sc. Fachgebiet für Energie- und Kraftwerkstechnik L1|08 114 Technische Universität Darmstadt Jovanka-Bontschits-Straße 2 D-64287 Darmstadt Germany
Tel.: +49 6151 16 - 28915 Fax: +49 6151 16 - 6555 e-mail: lackhove@ekt.tu-darmstadt.de
-- Kilian Lackhove, M.Sc. Fachgebiet für Energie- und Kraftwerkstechnik L1|08 114 Technische Universität Darmstadt Jovanka-Bontschits-Straße 2 D-64287 Darmstadt Germany
Tel.: +49 6151 16 - 28915 Fax: +49 6151 16 - 6555 e-mail: lackhove@ekt.tu-darmstadt.de
participants (2)
-
Kilian Lackhove
-
Selbach, Fabian