I have been using EFDC for current simulation due to density difference. For the simulation to be stable, I have to run the model with very small time step. When I used efdc-explorer to check the model metrics-courant number, they are pretty small in the range of 1*10e-3. Does this small values of Courant no. affect the simulation results (unwanted numerical diffusion etc.) other than taking longer time to finish the simulation?
There are some numerical issues associated with such a small Courant number, or conversely a number that is too high. 1 is the theoretical maximum. Is 1*10e-3 the peak or the smallest number? However, the main problem with such a small number is the longer time for the model run.