DNS-LES pore scale simulation of thermal multi-component, multi-phase flow including radiative heating

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This subproject focuses on the investigation of several important issues in the context of modeling thermal multiphase, multicomponent flows including evaporation in porous media. One problem is the computation of mass, momentum and energy flux from a combined Direct Navier-Stokes and Large-Eddy-Simulation (DNS-LES) model at the interface of the pore-scale porous medium and the first decimeters of the atmospheric boundary layer to generate calibration data for larger scale Reynolds averaged Navier-Stokes (RANS) models developed in SP2. These simulations will be validated with wind tunnel data obtained in SP5. Another problem is related to the pore scale simulation of inertia effects (e.g. Hains jumps) to investigate pore scale transition lengths, front waiting times and front velocities for different processes (infiltration, imbibition, evaporation and drainage) to support the investigation of the applicability of the Richards equation conducted experimentally in SP5 for Hele-Shaw cells containing sintered glass beads or sand particles. In addition we will investigate solute concentration gradients for both stable and unstable interface motion scenarios. For these simulations we will develop a new kinetic free surface model avoiding the numerical discretization of the strong density gradients at the air-water interface which were difficult to resolve with previous Lattice-Boltzmann models. A large part of the simulations will be conducted on massively parallel General Purpose Graphics Processing Units (GPGPU) hardware to substantially reduce the computational efforts associated with three-dimensional transient computations with more than a billion degrees of freedom.