Siegfried Raasch, Leibniz University of Hannover
Large-eddy simulation, atmospheric turbulence
PALM is a large-eddy simulation (LES) model for atmospheric and oceanic flows which is especially designed for performing on massively parallel computer architectures. PALM is free software. It can be redistributed and/or modified under the terms of the GNU General Public License (v3).
PALM solves prognostic equations for velocity (Navier-Stokes equation), temperature (first law of thermodynamics) and humidity (transport equation for scalar). A Boussinesq approximation for incompressible fluids is used. Equations are discretized on a cartesian staggered grid using finite differences.
Some of PALM's highlights are:
The input parameter file describes a model setup for idealized atmospheric convection. The atmosphere is initially at rest and heated from the surface with a constant rate of about 100 Watt per square meter.
The output file serves as a standard check for the reliabilty of the simulation results. One line is output per model timestep. Beside the simulated time, it mainly displays the temporal evolution of the absolute maximum of the three velocity components (umax, vmax, wmax) in meter per second.
Raasch, S. and M. Schröter, 2001: PALM - A large-eddy simulation model performing on massively parallel computers. Meteorol. Z., 10, 363-372. DOI: 10.1127/0941-2948/2001/0010-0363. pdf