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Numerical simulations on passenger vehicles equipped with a cover under transportation

Jaime Mateo Barroso
Göteborg : Chalmers tekniska högskola, 2017. Diploma work - Department of Applied Mechanics, Chalmers University of Technology, Göteborg, Sweden, ISSN 1652-8557; 2017:43, 2017.
[Examensarbete på avancerad nivå]

The concern of the car companies to offer an image of quality to their clients has led to take care of every single detail. An example of this, is that newly produced cars are now being covered during their transportation on trucks. The design of the covers involve several wind tunnel tests for each new car model. This has high cost in time and resources. The aim of this work is trying to develop the first step on a procedure to conduct numerical simulations to extract the information needed to optimise the design process and reduce the number of tests in the wind tunnel. The cover is a deformable material and its behaviour can be compared to sails. The behaviour of sails under up-wind conditions has been studied over the last years and some parts of its method can be applied to the current work. The study is performed on the generic model DrivAer, which is an open source model especifically created for aerodynamic studies. The process consists in simulating three different cases on which a variation on the cover geometry is applied, starting from the car model itself and applying successive modifications to generate a more realistic model. The first simulation is thus the model itself and the results obtained are used for the next case, in which a wrapping is applied to the car, to resemble the uneven surface of the cover. The third case consists on generating a geometry that resembles the cover alone, by means of morphing the original model. The last case allows to simulate two geometries at the same time (cover and vehicle) and the flow in between. On the first two cases only the pressure on the outer surface is obtained, whereas on the third case the pressure is obtained on the outer and inner surfaces of the cover. The results obtained from the wall shear stress made clear that the next step should be a structural analysis to find the actual stress on the cover. Finding the pressure difference on the surfaces of the cover (in the third case) is essential to perform the structural analysis and with that, predict the deformation and stress.

Nyckelord: DrivAer, CFD, ANSA, Star-CCM+, aeroelastic analysis, car covers

Publikationen registrerades 2017-07-05. Den ändrades senast 2017-07-05

CPL ID: 250507

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