VOLUME EXCLUSION FOR REDUCING COMPRESSIBILITY EFFECTS IN LATTICE BOLTZMANN MODELS

摘要

Lattice Boltzmann (LB) models for ideal gases retrieve the Navier-Stokes equation in the incompressible limit. Nevertheless, the high values of the isothermal compressibility introduce serious drawbacks. In the simulation of liquid flows through porous media, the high pressure gradients through throats and tortuous paths produce significant errors when conventional LB models are used, especially when the interest is the transient flow. In this work a significant reduction of the isothermal compressibility is reached by adjusting the equilibrium distribution moments to those obtained imposing a van der Waals pressure-density dependence and adopting a lattice with a high number of speeds. Simulation results for the shock tube problem, the velocity step problem and the transient pressure response in a tortuous channel are presented and compared with available analytical results.