diff --git a/docs/turbulence.md b/docs/turbulence.md index 73d7ac47..b51b4b70 100644 --- a/docs/turbulence.md +++ b/docs/turbulence.md @@ -47,7 +47,7 @@ k_2_0 = +1 ... ``` -Following parameters can be changed to control both the initial state +The following parameters can be changed to control both the initial state: - `rho0` initial mean density - `p0` initial mean thermal pressure @@ -63,7 +63,7 @@ Following parameters can be changed to control both the initial state - `z0=0.5` (default) - and radius `loop_rad=0.25` -as well as the driving field +as well as the driving field: - `kpeak` peak wavenumber of the forcing spectrum. Make sure to update the wavemodes to match `kpeak`, see below. - `corr_time` autocorrelation time of the acceleration field (in code units). @@ -74,10 +74,17 @@ Using delta-in-time forcing, i.e., a very low value, is discouraged, see [Grete https://doi.org/10.1051/0004-6361/200912437). - `accel_rms` root mean square value of the acceleration (controls the "strength" of the forcing field) - `num_modes` number of wavemodes that are specified in the `` section of the parameter file. -In order to generate a full set of modes run the `inputs/generate_fmturb_modes.py` script and replace +The modes are specified manually as an explicit inverse FT is performed and only modes set are included (all others are assumed to be 0). +This is done to make the global inverse FT possible without any +expensive communication between blocks but this becomes excessively +expensiv for large number of modes. +Typically using a few tens of modes is a good choice in practice. +In order to generate a set of modes run the `inputs/generate_fmturb_modes.py` script and replace the corresponding parts of the parameter file with the output of the script. Within the script, the top three variables (`k_peak`, `k_high`, and `k_low`) need to be adjusted in order to generate a complete set (i.e., all) of wavemodes. +Important, the `k_peak` in the script should match the `k_peak` set +in the input file. Alternatively, wavemodes can be chosen/defined manually, e.g., if not all wavemodes are desired or only individual modes should be forced.