DNS-LES pore scale simulation of thermal multi-component, multi-phase flow including radiative heating
Zusammenfassung der Projektergebnisse
Concerning flow regimes at high Reynolds numbers for soil-atmosphere interface, one has to couple a flow model for the turbulent boundary layer to the typical laminar behavior inside the porous media. In the subproject SP1 we conducted the DNS-LES simulations in the region of turbulent boundary layer above two geometries with the clearly contrasted roughness to study how the ratio of the characteristic roughness length-scale and thickness of viscous layer affects velocity profile in terms of roughness Reynolds numbers ks+. An intermediate success of our DNS-LES approach has been achieved to predict accurately viscous layer for small roughness Reynolds number and penetration depth for turbulent rough flow in terms of the relatively highpermeable soil surface. The ansatz decoupling the long term evaporation and transient update of turbulent motion has been applied to compute the dynamic equilibrium of mass and momentum flux in the turbulent boundary layer for the discrete saturation levels. The equilibrium diffusive fluxes of water vapor in terms of the three decreasing liquid saturation states have been derived as the corresponding drying rates, by which the transition of the drying stage I to stage II is identified successfully. The penetration depth of the turbulent eddies in the soil is supposed to play a role to control the regime of drying rate in stage I. A new efficient multiphase model based on lattice Boltzmann kernels by Banari et al. (2014) has been designed to the applications with the real density ratio of water and air to simulate the motion of interface at high Reynolds number. The numerical schema of the LB multiphase modeling differs from the conventional models which we have developed, however it demonstrates numerically the appropriate motion of the diffuse interface successfully in the benchmark tests and the applications with ocean surface wave and air-sea interaction. For the study of solute transport at the pore scale we applied the cumulant LB kernel and advection diffusion extension comparing with other pore scale models to simulate three dimensional images of fluid flow through a centimeter-scale column packed randomly with 6864 uniform beads, in which the fluid images are generated by high resolution magnetic resonance velocimetry (MRV). The simulated velocity fields are used to evaluated the macroscopic pressure drop, permeability, point-wise comparison of fluid velocity values at selected locations, and velocity distributions. All obtained simulation results were in good agreement when differences in model configuration were properly accounted for, although some minor discrepancies were observed.
Projektbezogene Publikationen (Auswahl)
- Extended lattice Boltzmann method for numerical simulation of thermal phase change in two-phase fluid flow. Phys. Rev. E, 88(1), 013304, 2013
H. Safari, M. H. Rahimian and M. Krafczyk
(Siehe online unter https://doi.org/10.1103/PhysRevE.88.013304) - Turbulent jet computations based on MRT and Cascaded Lattice Boltzmann models. Computers & Mathematics with Applications, 65(12), 1956-1966, 2013
S. Geller, S. Uphoff and M. Krafczyk
(Siehe online unter https://doi.org/10.1016/j.camwa.2013.04.013) - Consistent simulation of droplet evaporation based on the phase-field multiphase lattice Boltzmann method. Phys. Rev. E, 90(3), 033305, 2014
H. Safari, M. H. Rahimian and M. Krafczyk
(Siehe online unter https://doi.org/10.1103/PhysRevE.90.033305) - Efficient GPGPU implementation of a lattice Boltzmann model for multiphase flows with high density ratios. Computers & Fluids, 93, 1-17, 2014
A. Banari, C. Janßen, S. T. Grilli and M. Krafczyk
(Siehe online unter https://doi.org/10.1016/j.compfluid.2014.01.004) - DNS/LES studies of turbulent flows based on the cumulant lattice boltzmann approach. High Performance Computing in Science and Engineering’14, 519-531, 2015
M. Krafczyk, K. Kucher, Y. Wang and M. Geier
(Siehe online unter https://doi.org/10.1007/978-3-319-10810-0_34) - Intercomparison of 3D pore-scale flow and solute transport simulation methods. Advances in Water Resources, 2015
X. Yang, Y. Mehmani, A. P. William, A. Pasquali, M. Schönherr, K. Kim, M. Perego, M. L. Parks, N. Trask, M. T. Balhoff, M. C. Richmond, M. Geier, M. Krafczyk, L. S. Luo, A. M. Tartakovsky, T. D. Scheibe
(Siehe online unter https://doi.org/10.1016/j.advwatres.2015.09.015) - The cumulant lattice Boltzmann equation in three dimensions: Theory and validation. Computers & Mathematics with Applications, 70(4), 507 - 547, 2015
M. Geier, M. Schoeonherr, A. Pasquali and M. Krafczyk
(Siehe online unter https://doi.org/10.1016/j.camwa.2015.05.001)
