No frequency computed:

Error

Not a single frequency can be computed with in the requested frequency limit. Please increase the range of requested frequencies under Simulation Control.

What happened?

The solver failed to compute the frequency(ies) with in the requested frequency limit for the specific problem case.

What could be the possible reason?

This error occurred due to assignment of the frequency limit which is out of range for this specific problem case. This means that not a single frequency can be found with in the requested lower and upper frequency limit given under Simulation Control for this problem.

What can I do now?

In general, first try to give an open range e.g. starting from 0 to 10000 in order to capture the possible frequency limit for your case. Once you get the lower and upper limit from the Eigenfrequency table in Post-Processor, you can than provide the new lower and upper frequency limit with in this range in order to capture the frequencies you are interested in. An example below elaborates this issue in more detail:

  • Let’s suppose we want to do an acoustic analysis without knowing the range under which the frequencies can be found. Than as a starting point, we can calculate the frequencies by using the following formula:
CA acoustic frequency formula
\(c\) is the speed of sound, \(l_x\), \(l_y\) and \(l_z\) are bounding box dimensions of the geometry under consideration in x, y and z direction respectively and \(l\), \(m\), \(n\) = \(0,1,2,...\)
  • If still unsure about the range, we can also do the analysis with an open range from 0 to 10000. This gives the following eigenfrequency table which is shown in the figure below:
CA eigenfrequency table
  • Now as a next step, if we redo the same analysis with the range which is either in between the two frequencies from the above table e.g. between 226 and 238 Hz or which is higher than the upper limit for the same number of frequencies e.g. between 500 and 1000 will lead to this error.

  • On the other hand, giving a range e.g. between 205 and 270 will give the solution for total of 7 frequencies.

Note

If none of the above suggestions did solve your problem, then please post the issue on our forum or contact us.