1,720,968 research outputs found
Analisi Sperimentale dell'Interferenza Aerodinamica Ruota-Passaruota per la Vettura F131Evo
No full textReport of Depart. of Aerospace Eng. of Pisa, DDIA 2004-4, Feb. 2004
Progetto Aero-Termodinamico di un Sistema di Raffreddamento: Analisi di Sensibilita'
No full textReport of Depart. of Aerospace Eng. of Pisa, DDIA 2004-6, Mar. 2004
Climate Control And HVAC Simulation For Occupied Spaces in Cars Using Open Source Software
No full textProgetto Aero-Termodinamico Di Un Sistema Di Raffreddamento: Analisi Della Procedura
No full textReport of Depart. of Aerospace Eng. of Pisa, DDIA 2004-5, Feb. 2004
Use of the CFD for the analysis of the exhausts trajectory
No full textThe problem of the evaluation of the trajectory of the gas exhaust is important in a car project, because its particular impact on the comfort level. For the high performance cars the problem could be critical, because the high level of deceleration of the car during the braking phase.
From the computational point of view the problem appears really challenging. In fact, it is necessary to made an unsteady evaluation, following the car in its velocity history. Furthermore, the geometry representation must be very refined, because the problem is highly related to the small details, and a corrected representation of all the geometrical elements is necessary to avoid an uncorrected analysis of the resulting flow. This imply really high requirements in computational capabilities, and HPC appears essential.
In order to make an assessment of this problem, a numerical procedure, be presented in the present paper, was settled. The numerical procedure is based on the CFD code Ansys-Fluent 14.5, by using a RANS approach with a realizable k-ε model and non-equilibrium wall function.
The reference car is the Ferrari production one. The geometry representation is very refined, and the volume grid is represented by about 60 millions of cells.
Both the time history of the car velocity and the gas mass flow rate are given, defined by means of user-defined functions, and the evaluation was made following them.
The total time of the simulation was 20 s, with a time step of 0.01 s and 10 internal iterations.
In order to analyse the trajectory of the exhaust gas a particle tracking technique was used, by activating the discrete phase model. The injection zone was coincident with the exhausts. As an example, the particle traces at a given time step is shown in fig. 1.
The evaluation was made on a 512 cores cluster in about 4 days.
The results of the numerical evaluation has been confirmed by the analysis of the real behaviour, and the presented results given an important support to define a geometrical set-up suitable to avoid the problem of the interference between the car and the gas exhaust, with a consequent improvement in the comfort level
Correction of Wind Tunnel Data: a Numerical Analysis of the Different Contributions
No full textThe experimental data corrections on automotive wind tunnel test usually take profit by the pre-test corrections methodology, which is able to breaking down the working time.
This methodology is based on the use of CFD simulations and carries out a global correction factor. It is interest to analyze the different contributions to the correction (wind tunnel walls effects, supports, Reynolds number) and their eventual dependence by the involved parameters.
Therefore, in the present paper, the main purpose is to describe, with the support of a CFD analysys, the influence of the main factors that contribute to the final correction factor.
A high performances car was taken as reference model and the RANS equations were used as fluid dynamic model. In a preliminary part the CFD methodology and its validation, through a comparison with experimental data, are presented.
The different contribution to the correction terms are presented and discussed. Finally, for each of these factors, the contribution of the different parts of the car is evaluated. The car was splitted in body, wheels, underbody, radiators, internal ducts and volumes and rear wing
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