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Aerodynamics plays a key role in nowadays vehicle development, aiming efficiency on fuel consumption, which leads to a green technology. Several initiatives around the world are regulating emissions and efficiency of vehicles such as EURO for European Marketing and the INOVAR Auto Project to be implemented in Brazil on 2017. In order to meet requirements in terms of performance, especially on aerodynamics, automakers are focusing on aero-efficient exterior designs and also adding deflectors, covers, active spoilers and several other features to meet the drag coefficient. Usually, the aerodynamics properties of a vehicle are measured in both CFD simulations and wind tunnels, which provide controlled conditions for the test that could be easily reproduced. During the real operations conditions, external factors can affect the flow over the vehicle such as cross wind in open highways.

The automakers pursue for fuel economy is increasing year after year, both by the demands of society and by political pressures, leading companies to develop new solutions and technologies in order to increase the energy efficiency of vehicles. With the advent of CFD software, it is possible to study drag reduction proposals, which contributes to increase fuel economy. In this context, based on a small sedan vehicle virtual drag model, correlated with the wind tunnel test, a conceptual wheel was assembled proposing 3 blade angles in order to verify the influence on the drag coefficient. Considering the drag contribution of wheel in total vehicle drag is around 25%, this work aims to show the sensitivity in the drag coefficient by changing the wheel rim of a small sedan vehicle.

Cargo trucks are one of the most important and flexible ways of moving cargo within inlands. In some countries, such as Brazil, the economy relies on them to transport all kinds of products, from field and factory to consumer. In order to reduce freight prices, beside route optimization, truck manufactures started to focus on the aerodynamics development of those vehicles, in order to improve the efficiency, reducing fuel consumption and emissions. Although the truck aerodynamics development is important, most vehicles are not manufactured or don’t consider the truck trailer, which plays a key role in the full aerodynamics performance of the truck, once it might increase the front area and also change the overall aero performance.

The Ahmed Body is one of the most widely studied bluff bodies used for automotive conceptual studies and Computational Fluid Dynamics - CFD software validation. With the advances of the computational processing capacity and improvement in cluster costs, high-fidelity turbulence models, such as Detached Eddies Simulation – DES and Large Eddies Simulation – LES, are becoming a reality for industrial cases, as studied by BUSCARIOLO et al. (2016) [4], evaluating DES models to automotive applications. This work presents a correlation study between a computational and physical model of an Ahmed Body with slant angle of 0 degree, also known as a squared back. Physical results are from a wind tunnel test, performed by STRACHAN et al. (2007) [11] considering moving ground and Reynolds number of 1.7M, based on the length of the body.

Moving ground simulation plays an important role on aerodynamic studies of road vehicles, in order to reproduce the real movement condition. Due to cost of implementing a moving ground, many wind tunnels employ static ground simulation with boundary layer control. The work here presented aims to study using Computational Fluid Dynamics - CFD simulations the effect of using moving ground simulations with rotating wheels against a baseline configuration using both static ground and wheels over a small pick-up truck. The study aims to determine the influence of using different flow velocities on the drag coefficient measured over this vehicle using both ground configuration. For the cases here presented we performed steady state Reynolds-Averaged Navier-Stokes - RANS numerical simulations, following similar setup as the industry best practices and using the same mesh.

This study refers to the Computational Fluid Dynamics, demonstrating a comparative between the drag coefficient and the frontal area of a current production car with the same values obtained from a conceptual proposal of removing the outside rearview mirrors of this same vehicle. Both cases were simulated in a virtual wind tunnel with moving ground and rotating wheels condition at speed of 100 kph, aiming to represent the best way a car moving on a highway. The main objective of this paper is improving the efficiency of automotive vehicles by replacing the current outside rearview mirror for cameras placed in smaller structures. The first simulation showed that by removing the outside rearview mirrors both the frontal area of the car and the drag coefficient, which has direct influence on fuel economy calculation, are smaller compared to current solution.

Aerodynamics plays a critical hole in open wheels race cars. The work here presented shows a comparative study of different undertrays design and their influence over the drag coefficient measured on an open wheel prototype race car, using CFD simulations in a virtual wind tunnel. For all cases, velocity was 60 km/h and it was considered both moving ground and rotating wheels to look for a more realist representation of the real interaction between car and racetrack. One model without any aero-part was taken as baseline and three different undertrays proposals were evaluated looking for an aerodynamic improvement. As final results, the drag coefficient of the proposals were ranked and compared with baseline results. Also pressure, velocity and wake images help to illustrate the improvements on the drag coefficient by using an undertray in this vehicle.

Thanks to advances in Computational Fluid Dynamics - CFD codes, i.e. algorithms and turbulence models, complex CFD vehicles simulations are increasing not only in academia, but also in the industry itself. The aim of the simulations is to verify the aerodynamic behavior of a car at early stages of the project, when no prototype is available, and to reduce the total aerodynamic development time of a new vehicle. The turbulence model considered in the CFD simulation should be able to capture the main flow effects around the vehicle. Most importantly, the predicted total drag value of the vehicle has to be comparable to the values obtained in wind tunnel tests. The main focus of the presented work is a comparison of wind tunnel and CFD results of the same small production hatchback vehicle.

The work here presented aims to study different types of ground configurations, located at the test section of a wind tunnel and to check their influence on the drag coefficient of one car, using only computer simulations. The drag coefficient of a vehicle is one of the most important aerodynamic proprieties, and as low as this drag value can be, the car performance will increase and the fuel consumption will decrease, item which has been pursued in new vehicles. Starting from one real wind tunnel test of a small pickup, with static test section ground, a virtual model was built and tested using CFD, following the same configuration of the real test. The difference between test and simulation results was 0.25%, showing that the methodology here used is reliable. After that, two other types of ground were simulated: elevated plate and moving belt and the results show that drag value decreased 0.002 and 0.012 respectively, compared to the value obtained with static ground simulation.

Nowadays, one of the most important roles in vehicle development is the aerodynamic, which aims efficiency on fuel consumption and leads to a green technology. Several initiatives around the world are regulating emissions and efficiency of vehicles such as EURO for European Marketing and the INOVAR Project to be implemented in Brazil on 2017. Thus, this study intend to perform an optimization to minimize the drag force of a hatchback vehicle. The main goal of this work is demonstrate the potential of optimization techniques to provide an aerodynamic shape improvement for the driver side outside rear view mirror of a hatchback vehicle. The optimization solver used in this work is the Adjoint Solver, which makes shape sensitivity analysis and mesh/volume morphing. The study was conducted using CFD simulations to reduce the drag force of current production hatchback vehicle previously validated and correlated in wind tunnel test.