Detached Eddy Simulation of an Aircraft Jet Flow Using an OpenSource CFD Code

This thesis work is part of a preliminary study for the project "High-performance computing and data-driven modeling of aircraft contrails", granted by the US NFS (National Science Foundation) and with PI Prof. Roberto Paoli of the Illinois University of Chicago (UIC). The aim of the project is the prediction of contrail formation in fully-three dimensional turbulent jets exhausting from the aircraft nozzle. The target of the work is to analyze the first phase of the contrail formation, the so called Jet Phase, "where the aircraft jet is expanded into the atmosphere, mixed with the ambient air and cooled down to the atmospheric temperature". This phase occurs in the first 30 m behind the aircraft engine and the effect of the aircraft vortex is neglected. As a preliminary work, the simulations reported in the thesis take into account only the engine exhaust gases without adding the effect of soot particles that can act as nucleation sites for the sublimation of atmospheric water vapour. Since no experimental data for jet fows exiting from aircraft engines have been found in literature, the first part of the thesis is devoted to set-up the simulation parameters on the NASA near sonic jet validation case of a jet fow at Ma = 1 exiting from the ARN-2 nozzle. Then the geometry of the ARN-2 nozzle is rescaled in order to have the same exit diameter of the drain nozzle of the CFM-56 engine and the simulations considering the flight conditions are performed on axisymmetric and full 3D grids. Since the ARN-2 nozzle has an inner and an outer wall, the simulations consider the effect of the latter one on the flow physics. At the beginning a standard RANS model is used, while the final part of the work is completely devoted to set up the DES model and to compare the obtained results with the RANS cases.