Massively Parallel Computations of 3-D Reacting Transient Jets

In Direct Numerical Simulation, the great demand for both memory and CPU time is even increased dealing with chemical reactive phenomena. Hence, parallel computing techniques are needed. Only recently, DNS of reacting phe nomena has been approached in 3-D configuration [1, 2]. In this work, massively parallel computations of a three-dimensional reacting transient jet are presented. The simulations have been performed on a Linux Beowulf Cluster HP-IA32, with 36 biprocessor nodes ProLiant DL360. An MPI DNS code has been developed and its performance has been assessed by computing the characteristic parameters of the parallel implementation. The values of speed up show good scalability of the code. An initial computation has been carried out by simulating the n-heptane ignition in a transient jet with a detailed kinetic mechanism [3]. As a consequence of the choice of initial conditions, the ignition takes place in the early stages of the development of the mixing and the phenomenon is mainly dominated by the large two-dimensional vortex structures [4]. Hence, the results, in terms of ignition delay time and localization of ignition spots, are comparable with those obtained in two-dimensional configurations [5]. Next, the influence of 3-D vortex stretching on the ignition phenomenon will be anal ysed.