| 83 | | In the model, the maximum allowed time step according to CFL and diffusion-criterion [[dt_max]] is reduced by dt = dt_max * '''cfl_factor''' in order to avoid stability problems which may arise in the vicinity of the maximum allowed timestep. The condition 0.0 < '''cfl_factor''' < 1.0 applies.\\\\ |
| | 83 | In the model, the maximum allowed time step according to CFL and diffusion-criterion dt_max is reduced by [[dt]] = dt_max * '''cfl_factor''' in order to avoid stability problems which may arise in the vicinity of the maximum allowed timestep. The condition 0.0 < '''cfl_factor''' < 1.0 applies.\\\\ |
| | 84 | The default value of cfl_factor depends on the [[timestep_scheme]] used:\\\\ |
| | 85 | For the third order Runge-Kutta scheme it is '''cfl_factor''' = 0.9.\\\\ |
| | 86 | In case of the leapfrog scheme a quite restrictive value of '''cfl_factor''' = 0.1 is used because for larger values the velocity divergence significantly effects the accuracy of the model results. Possibly larger values may be used with the leapfrog scheme but these are to be determined by appropriate test runs.\\\\ |
| | 87 | The default value for the Euler scheme is '''cfl_factor''' = 0.8 . |
