  The fluid flow and heat transfer problems encountered in industry
applications span into different scales and there are different numerical
methods for different scales problems. It is not possible to use single scale
method to solve problems involving multiple scales. Multiscale methods are
needed to solve problems involving multiple scales. In this chapter,
meso-macro-multiscale methods are developed by combining various single scale
numerical methods, including lattice Boltzmann method (LBM), finite volume
method (FVM) and Monte Carlo method (MCM). Macroscale methods include FVM,
while LBM and MCM belongs to mesoscale methods. Two strategies exist in combing
these numerical methods. For the first one, the whole domain is divided into
multiple subdomains and different domains use various numerical methods.
Message passing among subdomains decides the accuracy of this type of
multiscale numerical method. For the second one, various parameters are solved
with different numerical methods. These two types of multiscale methods are
both discussed in this chapter.
