Sensitivity of drag coefficient on ground vehicles to different mesh strategies and turbulence models

Edoardo Beatrice

Sensitivity of drag coefficient on ground vehicles to different mesh strategies and turbulence models.

Rel. Renzo Arina, Matteo Gautero. Politecnico di Torino, Master of science program in Aerospace Engineering, 2023

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Abstract

The research conducted concerns the field of the computational fluid dynamics and considers various turbulence models of the Reynolds-averaged Navier-Stokes equations. The study has been carried out in collaboration with Politecnico di Torino and Stellantis, which uses this kind of model in order to predict how vehicles react to changes of geometry. The aim of this project is to analyze how changes in domain meshing processes and turbulence models, can affect the results of the drag coefficient Cx either on different geometry of the same vehicle and on different vehicles. In particular, deltas between different configuration studied will be shown. In order to conduct the study, two different aerodynamic simulation software has been used: ANSA and StarCCM+ (in collaboration with Siemens in order to develop a better algorithm of mesh and turbulence model).

The thesis is built in 4 different chapters: the first one is a brief introduction of the topic, which will be developed in following chapters; the second one contains the introduction to the laws which govern aerodynamic flows, the description of the turbulence models used (κ−ϵ, κ−ω, Elliptic Blending Models) and why they have been introduced in fluid-dynamic computation; the third chapter describes the process followed in order to achieve the results, explaining how many car models were used, which different processes of meshing were followed and which turbulence models were implemented; the fourth chapter is a conclusive one, in which all the results are analyzed and some additional analysis of the study are presented.