Boundary forces in lattice Boltzmann: Analysis of Momentum Exchange algorithm

When lattice Boltzmann methods are used to simulate fluid–structure interaction problems, they need to be coupled with additional routines to evaluate the boundary forces without destroying the efficiency and accuracy of the original method. We use the asymptotic expansion technique to analyze one such approach, the Momentum Exchange algorithm, investigating its properties in detail, whether it can be improved and in which cases it can be successfully used. A statement regarding the accuracy is presented, together with results of numerical tests which illustrate the theoretical considerations.