Hi Will, 5. I am quite not sure what "[solver-dual-time-integrator-multip]" is in dual-time-stepping solvers, since it is deletable and simulation becomes much faster when it is deleted.
In the artificial compressibility formulation, you need dual time stepping to recover time-accuracy. To put it shortly, the physical time is discretised with a BDF scheme whose solution is iterated with explicit pseudo-time stepping in fictitious time. The analogy to OpenFOAM is that the pseudo-time stepping is like solving the Poisson equation for pressure in more local way. [solver-dual-time-integrator-multip] enables polynomial multigrid acceleration in the pseudo-time. If it is enabled you perform pseudo-niters-max number of multigrid cycles within each time step. If you remove the multip field you perform pseudo-niters-max number of iterations, not cycles. So if you keep pseudo-niters-max constant, removing the field makes the simulation quicker, but it also means that your convergence is much worse. Cheers, Niki On 1 Nov 2017, at 21:58, Vincent, Peter E <[email protected]<mailto:[email protected]>> wrote: Hi Will, Thanks for your interest in PyFR. Does it mean that for fully incompressible fluid, artificial compressibility should be "ac-zeta = 0.0” ? No. You need some artificial compressibility for the approach to work. 1. How can I continue my simulation from the latest time step? You can restart from a .pyfrm/.pyfrs file (pyfr restart mesh.pyfrm solution.pyfrs) - see the User Guide online. 2. Is it able to map the flow field from one case to another case, even regardless the difference of mesh? (Something like "mapFileds" in OpenFOAM) No. 3. Is there any command in PyFR that we can export all .pyfrs files to .vtu files at once rather than export one time step by one time step? There have been other threads on this. For various reasons, it is best just to write a quick BASH script. 4. The output file is ".vtu", which is unreadable by text readers. Is there any command to export readable text file such as vtk, csv or text for the entire fluid field for post-processing? (Pretty similar to the output "U" and "p" file in OpenFOAM) 5. I am quite not sure what "[solver-dual-time-integrator-multip]" is in dual-time-stepping solvers, since it is deletable and simulation becomes much faster when it is deleted. Which simulation? Thanks Peter Dr Peter Vincent MSci ARCS DIC PhD FRAeS Reader in Aeronautics and EPSRC Fellow Department of Aeronautics Imperial College London South Kensington London SW7 2AZ UK web: www.imperial.ac.uk/aeronautics/research/vincentlab<http://www.imperial.ac.uk/aeronautics/research/vincentlab> twitter: @Vincent_Lab<https://twitter.com/Vincent_Lab> On 31 Oct 2017, at 03:45, Will <[email protected]<mailto:[email protected]>> wrote: Warning from Imperial College ICT: This message contains a link to a website sometimes used by "phishers" to steal credentials. Caution is advised when clicking on these links. To avoid credential theft, you should not enter your Imperial College username and password into any form linked from this message. The original messages continues below. ________________________________ Thanks Freddie, Does it mean that for fully incompressible fluid, artificial compressibility should be "ac-zeta = 0.0" ? Some other questions. 1. How can I continue my simulation from the latest time step? 2. Is it able to map the flow field from one case to another case, even regardless the difference of mesh? (Something like "mapFileds" in OpenFOAM) 3. Is there any command in PyFR that we can export all .pyfrs files to .vtu files at once rather than export one time step by one time step? 4. The output file is ".vtu", which is unreadable by text readers. Is there any command to export readable text file such as vtk, csv or text for the entire fluid field for post-processing? (Pretty similar to the output "U" and "p" file in OpenFOAM) 5. I am quite not sure what "[solver-dual-time-integrator-multip]" is in dual-time-stepping solvers, since it is deletable and simulation becomes much faster when it is deleted. Best regards, Will -- You received this message because you are subscribed to the Google Groups "PyFR Mailing List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]<mailto:[email protected]>. To post to this group, send email to [email protected]<mailto:[email protected]>. Visit this group at https://groups.google.com/group/pyfrmailinglist. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "PyFR Mailing List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]<mailto:[email protected]>. To post to this group, send email to [email protected]<mailto:[email protected]>. Visit this group at https://groups.google.com/group/pyfrmailinglist. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "PyFR Mailing List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. Visit this group at https://groups.google.com/group/pyfrmailinglist. For more options, visit https://groups.google.com/d/optout.
