| 354 | 354 | ||[=#PA0311 PA0311] ||number of gridpoints along x or/and y contain illegal factors only factors 2, 3, 5 are allowed ||In case that [../initialization_parameters#fft_method fft_method]='temperton-algorithm', the number of horizontal grid points ([../initialization_parameters#nx nx]+1, [../initialization_parameters#ny ny]+1) must be composed of prime factors 2,3 and 5. Higher prime factors such as 7 are not allowed. Please ensure that these restrictions are fulfilled or use 'singleton-algorithm' as [../initialization_parameters#fft_method fft_method]. || |
| 355 | 355 | ||[=#PA0312 PA0312] ||Time step has reached minimum limit. \\dt = ... s Simulation is terminated.\\old_dt = ... s\\dt_u = ... s\\dt_v = ... s\\dt_w = ... s\\dt_diff = ... s\\u_max = ... m/s k=... j=... i=...\\v_max = ... m/s k=... j=... i=...\\w_max = ... m/s k=... j=... i=... ||The time step is determined according to the CFL criterion to assure a stable numerical solution. This error message means that the required minimum time step, determined from the three velocity components, is several orders of magnitude smaller than [../runtime_parameters#dt_max dt_max], or, in other words, that at least one of the velocity components got too large. Due to the large number of complex reasons it should be noted that this list is not complete, but it is intended to give general hints how to proceed in case of this error message. First, check for a unrealistic value of [../runtime_parameters#dt_max dt_max] in the NAMELIST file. Moreover, this error message may indicate for unrealistic settings of e.g. [../initialization_parameters#bc boundary conditions] or other NAMELIST parameters. For very small vertical grid spacing [../initialization_parameters#dz dz] this error might also occur if [../initialization_parameters#roughness_length roughness_length] >= [../initialization_parameters#dz dz]. Please also check if this error appears if you run without USERCODE. To compile and run the PALM and USERCODE with DEBUG-options might also give sometimes valuable hints. In case the [../land_surface_parameters land-surface model] or the [../urban_surface_parameters building-surface model] is employed, surface temperatures might had become unstable during the time-integration. One known issue is e.g. the presence of metal surfaces {{{pavement_type = 7}}}, where the integration of surface tempertures can become unstable, producing unrealistically high or low surface sensible heat fluxes. Please check for possibly mis-represented settings in your static input file. List to be continued.|| |
