PORE-SCALE COMPUTATION OF PERMEABILITY AND DIFFUSION TENSOR OF ANISOTROPIC POROUS MEDIA WITH LATTICE BOLTZMANN METHOD

Abstract

This thesis reflects the work done in iRMB as a part of a sub-project A5 focusing on determination of two modelling parameters. Reduction of noise during the take-off and landing of an air-craft is the need of the hour in order to make use of the excess vacant land near the airports. This calls for the design of community-friendly aircrafts with short take-off and landing lengths. This matter is being handled by Collaborative Research Centre (CRC) 880 in Braunschweig, Germany. Out of all the sub-projects under CRC 880, this dissertation is a part of the sub-project A5 which is focussed on Pore resolving LES simulation of porous materials which deals with turbulence related source of sound. A major goal of subproject A5 is to investigate the aeroacoustic effect of permeable materials in laminar and turbulent flow by pore-scale simulations using DNS and LES methods within and in the boundary layer of porous materials. Further to study the aerodynamics and aeroacoustic effect of porous inlays, one requires two main modelling parameters, permeability and diffusion tensor. This dissertation runs the simulations first on isotropic cube to check for the validity of the LBM code and then runs the simulations on various anisotropic setups in order to calculate the permeability tensor and Forchheimer coefficient. The results produced in this thesis are for the Anisotropic PA80-110 Gradiert. The results from this report are going to be inserted in volume averaged Linearized Euler Equations(LEE) which is obtained from volume averaged Navier Stokes Equation where in all additional terms representing viscosity, heat conduction, subfilter stresses and entropy-modes were omitted in the context of sound propagation. The remaining terms are modeled by the Darcy and Forchheimer terms of the momentum equation.