| 20 | | Averaging interval for all output of temporally averaged data (in s).\\\\ |
| 21 | | This parameter defines the time interval length for temporally averaged data (vertical profiles, spectra, 2d cross-sections, 3d volume data). By default, data are not subject to temporal averaging. The interval length is limited by the parameter |
| 22 | | [[#dt_data_output_av dt_data_output_av]]. In any case, '''averaging_interval <= dt_data_output_av''' must hold.\\\\ |
| 23 | | If an interval is defined, then by default the average is calculated from the data values of all timesteps lying within this interval. The number of time levels entering into the average can be reduced with the parameter [#dt_averaging_input dt_averaging_input].\\\\ |
| 24 | | If an averaging interval can not be completed at the end of a run, it will be finished at the beginning of the next restart run. Thus for restart runs, averaging intervals do not necessarily begin at the beginning of the run.\\\\ |
| 25 | | Parameters [#averaging_interval_pr averaging_interval_pr] and [#averaging_interval_sp averaging_interval_sp] can be used to define different averaging intervals for vertical profile data and spectra, respectively. |
| | 20 | Near-surface adjustment of the mixing length to the Prandtl-layer law. |
| | 21 | |
| | 22 | Usually the mixing length in LES models lLES depends (as in PALM) on the grid size and is possibly restricted further in case of stable stratification and near the lower wall (see parameter wall_adjustment). With adjust_mixing_length = .T. the Prandtl' mixing length lPR = kappa * z/phi is calculated and the mixing length actually used in the model is set l = MIN (lLES, lPR). This usually gives a decrease of the mixing length at the bottom boundary and considers the fact that eddy sizes decrease in the vicinity of the wall. |
| | 23 | |
| | 24 | Warning: So far, there is no good experience with adjust_mixing_length = .T. ! |
| | 25 | |
| | 26 | With adjust_mixing_length = .T. and the Prandtl-layer being switched on (see prandtl_layer) '(u*)** 2+neumann' should always be set as the lower boundary condition for the TKE (see bc_e_b), otherwise the near-surface value of the TKE is not in agreement with the Prandtl-layer law (Prandtl-layer law and Prandtl-Kolmogorov-Ansatz should provide the same value for Km). A warning is given, if this is not the case. |
