Coupling of a Combustion Code with an Incompressible Navier-Stokes Code on MIMD Architecture

This chapter highlights 3D combustion flames in liquid as a reaction process of frontal polymerization, which is investigated to design new materials that cannot be produced by classical processes. Two separate parallel codes were developed for each physical model. The first code solves the incompressible unsteady Navier-stokes equations with the Boussinesq approximation using semi-implicit finite differences methods. The second code solves 3D combustion problems using an implicit pseudo-spectral method in the direction perpendicular to the front and a high order explicit finite differences schemes. The chapter describes the physical models for the propagation of a combustion flame in a liquid and introduces the time discretization, the space discretization, the solvers and the boundary conditions for numerical scheme. The inter-program communication library is presented. It is possible to use all the computing power of parallel computer in a user friendly manner provided by the code coupling library. Experiments have shown that the inter-program communication cost can be as small as 0.2% of the total cost; thus, the overhead generated by library is acceptable. For application, the data to be moved are large 3D arrays. As a result, a good overlapping of communication and computations is crucial to achieve good performances. The three components; the CB code, the NS code, and the code coupling library have already presented some interesting simulation of 3D Frontal Polymerization phenomena. Theses simulations tend to confirm that the convective effects lead to slow down the propagation Front.