Questions on implicit integration and file coupling in AcousticSolver (v5.2.0)
******************* 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 Nektar++ developers, I am a researcher at the University of Birmingham using AcousticSolver v5.2.0 on ARCHER2 to solve the acoustic perturbation equations. My work involves sparse source data for a mixing layer, and with only explicit schemes (for example RK4), I must use very small "TimeStep" to maintain stability(The smallest element size of the grid cannot be modified, as it is already the largest option for identify source). I have two questions: 1. Implicit integrator support Currently AcousticSolver does not include any implicit time�\integration methods. Could you provide a test or development version that includes an implicit scheme such as backward Euler or Crank�\Nicolson? If no such version exists, could you advise how I might modify the solver code to add an implicit integrator? 2. Errors when inputting files As shown in my code(figure below), I input the source data using the "COUPLING" element with TYPE="File" and provide a series of .pts files named in floating point format (%14.8E). I also set TIMEDEPENDENT="1" so that they are read in time order. Since the time interval between these files is much larger than my solver TimeStep, when I tried to adjust ReceiveSteps to read a new file every n steps, the solver still tried to load the file at each dt(TimeStep) and failed when the file at the interpolation time did not exist. Is there a way to instruct AcousticSolver to read coupling files strictly according to the ReceiveSteps schedule��i.e. to load only when a new file index is due��without triggering ��file not found�� errors at intermediate time steps? Any guidance or pointers to relevant code sections or example configurations would be greatly appreciated. Thank you very much for your time and assistance. Best regards, Dao University of Birmingham [cid:511f73a2-b6b1-4275-bc1a-e1a0ac686633]
Hi Dao, We do not have an implicit version of the AcousticSolver. However if you look at Merge Request (!1784)<https://gitlab.nektar.info/nektar/nektar/-/merge_requests/1784> there was a first attempt at making the Shallow Water solver implicit. This does work but also does need a preconditioned to be implemented to work most effectively. Best, Spencer. On 26 Jun 2025, at 16:27, dxz324@student.bham.ac.uk wrote: This email from dxz324@student.bham.ac.uk<mailto:dxz324@student.bham.ac.uk> 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 Nektar++ developers, I am a researcher at the University of Birmingham using AcousticSolver v5.2.0 on ARCHER2 to solve the acoustic perturbation equations. My work involves sparse source data for a mixing layer, and with only explicit schemes (for example RK4), I must use very small "TimeStep" to maintain stability(The smallest element size of the grid cannot be modified, as it is already the largest option for identify source). I have two questions: 1. Implicit integrator support Currently AcousticSolver does not include any implicit timeŠ\integration methods. Could you provide a test or development version that includes an implicit scheme such as backward Euler or CrankŠ\Nicolson? If no such version exists, could you advise how I might modify the solver code to add an implicit integrator? 2. Errors when inputting files As shown in my code(figure below), I input the source data using the "COUPLING" element with TYPE="File" and provide a series of .pts files named in floating point format (%14.8E). I also set TIMEDEPENDENT="1" so that they are read in time order. Since the time interval between these files is much larger than my solver TimeStep, when I tried to adjust ReceiveSteps to read a new file every n steps, the solver still tried to load the file at each dt(TimeStep) and failed when the file at the interpolation time did not exist. Is there a way to instruct AcousticSolver to read coupling files strictly according to the ReceiveSteps scheduleĄĒi.e. to load only when a new file index is dueĄĒwithout triggering Ą°file not foundĄą errors at intermediate time steps? Any guidance or pointers to relevant code sections or example configurations would be greatly appreciated. Thank you very much for your time and assistance. Best regards, Dao University of Birmingham <image.png> _______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk<mailto:Nektar-users@imperial.ac.uk> https://mailman.ic.ac.uk/mailman/listinfo/nektar-users
participants (2)
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dxz324＠student.bham.ac.uk
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Sherwin, Spencer J