3.9 Setup for turbulent inflow

Starting from version 3.5 PALM includes a so-called turbulence recycling method which allows a turbulent inflow with non-cyclic horizontal boundary conditions. The method follows the one described by Lund et al. (1998, J. Comp. Phys., 140, 233-258), modified by Kataoka and Mizuno (2002, Wind and Structures, 5, 379-392). The method is switched on by setting the initial parameter turbulent_inflow = .TRUE..

The turbulent signal A'(y,z) to be imposed at the left inflow boundary is taken from the same simulation at a fixed distance xr from the inflow (given by parameter recycling_width): A'(y,z) = A(xr,y,z) - A(z), where A(z) is the horizontal average between the inflow boundary and the recycling plane. The turbulent quantity A'(y,z) is then added to a mean inflow profile a(z) which is the horizontal (and temporal) average as calculated from a precursor run. This is done after each timestep.

So far (09/16/08), a turbulent signal is imposed to all prognostic variables except humidity (passive scalar) and salinity!

In order to avoid a continous growth of the turbulent layer with time, the height up to which turbulence is recycled is limited by parameter inflow_damping_height. By default, this height is calculated and taken from the precursor run.

The following tries to give a short recipe about how to create a proper setup for using the turbulence recycling method:

RUN_CONTROL_O out:loc:tr d3o# ~/palm/current_version/JOBS/$fname/MONITORING _o_rc
HEADER_O out:loc:tr d3o# ~/palm/current_version/JOBS/$fname/MONITORING _o_header
PLOT1D_PAR_O out:loc:tr pro# ~/palm/current_version/JOBS/$fname/OUTPUT _o_pr_par
PLOT1D_DATA_O out:loc:tr pro# ~/palm/current_version/JOBS/$fname/OUTPUT _o_pr_in

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