General

General

Why does the solver stop with the message “Run duration reached – Maximum simulation time” before the specified Total Time is reached?

    • FAQFAQ
      Participant

      This can occur when the timestep size is varying strongly, i.e. from 5[s] to 1e-3[s] from one timestep to the next, close to the Total Time. The reason is that the solver uses a tolerance to check if the total time is reached. This tolerance is by default set to 0.01. That tolerance value is multiplied with the current timestep (i.e. 5[s]) to obtain a dimensional tolerance value (here 0.05[s]). If the Simulation Time is closer than this tolerance to the Total Time , then the solver is stopped. Generally it is not advised to apply such strong changes in the timestep. But if that is required, then the problem can be solved by setting an appropriate tolerance with the following expert parameter: FLOW: EXPERT PARAMETERS: transient maxtime tolerance = 0.01 END END A value of 0.0 is allowed, but it is recommended to use a value such that the dimensional tolerance is smaller than the smallest timestep even for the largest timestep value. In the above example the tolerance should be set to a value smaller than 2e-4, so for example to 1e-4. (1e-4 * 5[s] = 5e-4[s] < 1e-3[s])