Numerical simulation of a jet in crossflow. Application to GRID computing

This work describes the LES and hybrid RANS/LES simulations for a rounded jet issuing normally into a cross-flow, also known as jet in cross-flow (JICF). This test case is particularly suitable to study the capability of LES and hybrid approaches because of the presence of both separated and non-separated boundary layer regions. Simulations are performed for a jet to cross-flow velocity ratio $R = 2$ and a $Re = 82000$, based on the cross-flow velocity and the jet diameter. The simulations are carried out using a numerical solver of 3D compressible flows, named AERO. Large scales coherent structures observed in experimental flow visualisations are reproduced in both the simulations and the obtained mean and turbulent statistics are compared to experimental data. LES simulations seem to follow in a better way the experimental results than LNS. In the second case, there is not sufficiant mixing between jet and cross-flow and thus the jet bends less and a too large recirculation bubble forms behind the jet. This test case has been chosen also because we can split the domain in two different regions, the pipe and the cross-flow, with a limited interface. This is a good characteristic in order to test GRID computing, which is another goal of this work. GRID computing is an alternative way to carry out parallel computations with respect to the classical clusters or parallel computers. It consists in using computers allocated in different sites exchanging data between the sites through the web (Internet). In the present work, GRID computing is tested for both JICF and for the flow in a pipe.