Wind Tunnel Pulsations and their Active Suppression

Wickern, Gerhard; Heesen, Wilhelm von; Wallmann, Steffen

doi:10.4271/2000-01-0869

Cited by 42 publications

(37 citation statements)

References 2 publications

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“…These results also clearly show a strong correlation between local drag reductions and shear layer oscillations at resonant conditions. These results are in accordance with the parametric study by Wickern et al (2000) on a wide range of vehicles that shows a systematic decrease in the drag coefficient. According to Wickern et al, this corruption of the measured aerodynamic coefficient is due to a horizontal buoyancy effect, i.e.…”

Section: Impact On the Aerodynamic Measurementssupporting

confidence: 94%

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Reduction of 3/4 open jet low-frequency fluctuations in the S2A wind tunnel

Amandolèse

Vartanian²

2010

Journal of Wind Engineering and Industrial Aerodynamics

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Section: Impact On the Aerodynamic Measurementssupporting

confidence: 94%

“…Efforts to understand the physics and to reduce the impact of those low frequency fluctuations on data quality and wind tunnel operation have been reported in many recent technical papers (Arnette and Buchanan, 1999;Wickern et al, 2000;Rennie et al, 2004;von Heesen and Höpfer, 2000).…”

Section: Introductionmentioning

confidence: 99%

Reduction of 3/4 open jet low-frequency fluctuations in the S2A wind tunnel

Amandolèse

Vartanian²

2010

Journal of Wind Engineering and Industrial Aerodynamics

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“…When moving downstream, energy shifts from small-scale eddies to large-scale eddies, which in turn shifts the dominant frequency from high to low frequencies. This flow instability manifests itself in the jet as an axisymmetric vortex ring in the jet shear layer (Wickern et al, 2000). In 1985, based on the open-jet wind tunnel of the German-Dutch Wind Tunnel (DNW) (Michel et al, 1985) measured a center distance between the central velocity of the nozzle and the hydraulic diameter of the nozzle in the downstream region of the open wind tunnel.…”

Section: Introductionmentioning

confidence: 99%

“…However, it generates high-frequency noise, which is unacceptable in aeroacoustics automotive wind tunnels. This passive method also has an effect on the axial static pressure gradient (Wickern et al, 2000). Some wind tunnels adopt active control methods to control low-frequency buffeting, such as Audi's ARC (Active Resonance Control) system, but the active maintenance means have higher maintenance costs in the later period, which limits the application of this control method in wind tunnels (Evert et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

On the Low Frequency Pressure Fluctuation in a 3/4 Open Jet Automotive Wind Tunnel

Jia

Zhu

Bao

et al. 2019

JAFM

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In the present research, a possible generation mechanism of low-frequency buffeting phenomenon based on a 1:15 open jet automotive wind tunnel was investigated. Evolution of vortex structures and pressure field in the plenum chamber have been visualized and analyzed by Large-eddy simulation (LES). It is shown that the low frequency pressure fluctuation is caused by the largescale structures and their interaction. Multiple proper orthogonal decomposition was adopted to analyze the flow field in the plenum chamber. The characteristic frequencies of the vortex-rings after pairing is the same as the dominant resonance of buffeting at this wind velocity.

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“…AUDI A6 VALIDATION CASE A further analysis of the simulation results is carried out using experimental data for the Audi A6, for which particularly detailed data are available. The data used for the validiation of this test case are obtained from experiments carried out in the Audi aeroacoustic wind tunnel [11,12]. Although this facility is equipped with technology for carrying out aerodynamic testing with full ground simulation (i.e.…”

Section: Volkswagen Red-model Validation Casementioning

confidence: 99%

Application of Detached-Eddy Simulation for Automotive Aerodynamics Development

Islam¹,

Decker²,

Villiers

et al. 2009

SAE Technical Paper Series

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This paper presents a complete methodology for performing finite-volume-based detached-eddy simulation for the prediction of aerodynamic forces and detailed flow structures of passenger vehicles developed using the open-source CFD toolbox OpenFOAM R. The main components of the methodology consist of an automatic mesh generator, a setup and initialisation utility, a DES flow solver and analysis and post-processing routines. Validation of the predictions is done on the basis of detailed comparisons to experimental wind-tunnel data. Results for lift and drag are found to compare favourably to the experiments, with some moderate discrepancies in predicted rear lift. Point surfacepressure measurements, oil-streak images and maps of total pressure in the flow field demonstrate the approach's capabilities to predict the fine detail of complex flow regimes found in automotive aerodynamics. Standard DES methods can cost an order of magnitude more than traditional methods, but optimisation and automation of mesh generation, setup and solution algorithms ensure quick turnaround times. Due to the fully parallel nature of these components, the entire process can be executed in a distributed fashion. Efficient solution algorithms provide exceptional accuracy when compared to Reynolds-averaged approaches without sacrificing stability, even when the flow exhibits high Courant numbers. The proposed methodology is highly customisable, which allows for targeted developments to suit the individual needs of aerodynamics CFD. On the basis of the results presented here, the methodology is found to be appropriate and suitable for use in the industrial development process.

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Wind Tunnel Pulsations and their Active Suppression

Cited by 42 publications

References 2 publications

Reduction of 3/4 open jet low-frequency fluctuations in the S2A wind tunnel

Reduction of 3/4 open jet low-frequency fluctuations in the S2A wind tunnel

On the Low Frequency Pressure Fluctuation in a 3/4 Open Jet Automotive Wind Tunnel

Application of Detached-Eddy Simulation for Automotive Aerodynamics Development

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