SimScale CAE Forum

How can time step and write options be made more intuitive?


#1

Fellow engineers,

to run a transient or quasi-static analysis, one of the last steps in the simulation setup on SimScale is always the definition of how/which time steps shall be computed as well for which ones the result field shall be written. For flow simulations this is currently done via two options:

  • Which time steps are computed is defined by Start and End time as well as the step length
  • For writing, one has a bunch of options, but the most common one is to specify an interval in which results shall be written for later post-processing

So the image below says basically that 1000 time steps of 1 sec shall be computed and only the last one (1000th) shall be written (classical setting for a steady-state analysis).

Here the question: I think this could be done more intuitive to make sure that users do not run into problems. Especially if one specifies too many time steps to be written, the results are very hard to handle. Do you have any suggestions on how this part of the interface could be done more intuitive?

Looking forward to your suggestions!

Best,

David


#2

I am working on quasi-static analysis and would like to define time steps manually. Start with large time steps, ramp to very fine time steps, then back to large time steps. I have looked into doing this using a table to define the initial time step length. Could you please elaborate on the information required in this table? From the dialog, it looks like it is expecting [time, value]. However, my intuitive expectation is to supply only [time] ex. (0, .1, .45, .50, .55, .9, 1)


#3

Hi @gbreslich, the specification for the time stepping table is the following:

  • you need two columns
  • the first defines the time step, the second the time increment from the last time step until the current one.

As an example take this table:

1, 0.2
5, 1.0
6, 0.01

This means:

  • Until time 1, use increments of 0.2s

  • from 1s to 5s use increment of 1s

  • until 6s use an increment of 0.01s

I agree, for a small amount of time steps your intuitive solution might be easier to understand, and we might also enable such a time stepping definition in the future. on the other hand, imagine how long your list would be if you would only have the easy time stepping from the example above (over 100 values), opposed to the short definition above.

Best regards,
Richard