The GIE S2A Full-Scale Aero-acoustic Wind Tunnel

Waudby-Smith, Peter; Bender, Trevor; Vigneron, Rémi

doi:10.4271/2004-01-0808

Cited by 34 publications

(14 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The facility is a closed loop circuit that is the copy at scale 2/5 of the full scale facility whose detailed description may be found in Waudby-Smith et al (2004). The plenum of the facility is sketched in Fig.…”

Section: Experimental Set-upmentioning

confidence: 99%

Fluid force and symmetry breaking modes of a 3D bluff body with a base cavity

Evrard

Cadot

Herbert

et al. 2016

Journal of Fluids and Structures

109

110

View full text Add to dashboard Cite

A cavity at the base of the squareback Ahmed model at Re 4 × 10 5 is able to reduce the base suction by 18% and the drag coefficient by 9%, while the geometry at the separation remains unaffected. Instantaneous pressure measurements at the body base, fluid force measurements and wake velocity measurements are investigated varying the cavity depth from 0 to 35% of the base height. Due to the reflectional symmetry of the rectangular base, there are two Reflectional Symmetry Breaking (RSB) mirror modes present in the natural wake that switch from one to the other randomly in accordance with the recent findings of Grandemange et al. (2013b). It is shown that these modes exhibit an energetic 3D static vortex system close to the base of the body. A sufficiently deep cavity is able to stabilize the wake toward a symmetry preserved wake, thus suppressing the RSB modes and leading to a weaker elliptical toric recirculation. The stabilization can be modelled with a Langevin equation. The plausible mechanism for drag reduction with the base cavity is based on the interaction of the static 3D vortex system of the RSB modes with the base and their suppression by stabilization. There are some strong evidences that this mechanism may be generalized to axisymmetric bodies with base cavity.

show abstract

Section: Experimental Set-upmentioning

confidence: 99%

Fluid force and symmetry breaking modes of a 3D bluff body with a base cavity

Evrard

Cadot

Herbert

et al. 2016

Journal of Fluids and Structures

109

110

View full text Add to dashboard Cite

show abstract

“…Audi, Wickern and Lindener (2000); BMW, von Heesen et al (1996); Chrysler, Walter et al (2003); DNW, Mercker and Pengel (1994); Ford (Europe), Volkert and Kohl (1987); Ford (US), Walter et al (2002); GIE S2A, Waudby-Smith et al (2004); Hyundai, Kim et al (2001); IVK/FKFS, Potthof et al (1994), Künstner et al (1995); Pininfarina, Cogotti (2006) Wall treatment is used to achieve two objectives. The first is to provide an anechoic environment within the test section, to create a close-to free-field environment by reducing the reverberation and reflection of sound waves from the noise sources of the vehicle.…”

Section: Aeroacousticsmentioning

confidence: 99%

The Effects of Unsteady On-Road Flow Conditions on Cabin Noise

Oettle¹,

Sims-Williams²,

Dominy³

et al. 2010

SAE Technical Paper Series

View full text Add to dashboard Cite

On-road, a vehicle experiences unsteady flow conditions due to turbulence in the natural wind, moving through the unsteady wakes of other road vehicles and travelling through the stationary wakes generated by roadside obstacles. There is increasing concern about potential differences between steady flow conditions that are typically used for development and the transient conditions that occur on-road. This work considers whether steady techniques are able to predict the unsteady results measured on-road, the impact of this unsteadiness on the noise perceived in the cabin and whether minor changes made to the geometry of the vehicle could affect this. Both external aerodynamic and acoustic measurements were taken using a full-size vehicle combined with measurements of the noise inside the cabin. Data collection took place on-road under a range of wind conditions to accurately measure the response of the vehicle to oncoming flow unsteadiness, with steady-state measurements taking place in full-scale aeroacoustic wind tunnels.Overall it was demonstrated that, using a variety of temporal and spectral approaches, steady techniques were able to predict unsteady on-road results well enough to assess cabin noise by correctly taking into account the varying on-road flow conditions. Aerodynamic admittance values remained less than unity in the sideglass region of the vehicle, with the exception of the the region nearest the A-pillar. The reducing unsteady energy at frequencies greater than 10 Hz, combined with the corresponding roll-off in admittance, implies that unsteady frequencies below 10 Hz affect the vehicle most, where the response remains quasi-steady.Quasi-steady cabin noise simulations allowed a subjective assessment of the predicted unsteady cabin noise, where the impact of cabin noise modulations were quantified and found to be important to perception. Minor geometry changes affected the sensitivity of cabin noise to changes in yaw angle, altering modulation and therefore having an important impact on the unsteady wind noise perceived on-road.iii DeclarationThe work in this thesis is based on research carried out at the School of Engineering and Computing Sciences, Durham University, UK. No part of this thesis has been submitted elsewhere for any other degree or qualification and it all my own work unless referenced to the contrary in the text.

show abstract

“…There are numerous examples in the literature of test section flow angularity measurements for subsonic and transonic wind tunnels [2][3][4][5][6][7][8][9][10][11][12][13][14][15], typically performed as part of commissioning activities during the start-up phase after construction or after an upgrade. However, investigations of the causes of flow angularity in the test section are less common.…”

Section: Introductionmentioning

confidence: 99%

Flow Angularity Investigations in an Automotive Slotted Wall Wind Tunnel

2019

View full text Add to dashboard Cite

The Volvo Cars aerodynamic wind tunnel has had a vortical flow angularity pattern in the test section since its original commissioning in 1986. The vortical flow nature persisted after an upgrade in 2006, when the fan was replaced and a moving ground system was introduced. It has been hypothesized that the cause for this flow angularity pattern was leakages around the heat exchanger installed in the settling chamber. The present paper tests this hypothesis by measuring the flow angularity in the test section before and after sealing the leakages. The findings show that the leakage path around the heat exchanger does not influence the flow angularity, and that the current pattern is different compared to the commissioning after the upgrade. This prompted an investigation of the influence from the turbulence screens, which were changed after the upgrade commissioning. These investigations indicate that the probable cause of the vortical flow angularity pattern is residual swirl from the fan. Force measurements on a reference car with and without extra induced flow angularity show that the flow angles measured in the tunnel for regular operation are most likely small enough to not have a significant effect on the measured aerodynamic forces.

show abstract

The GIE S2A Full-Scale Aero-acoustic Wind Tunnel

Cited by 34 publications

References 11 publications

Fluid force and symmetry breaking modes of a 3D bluff body with a base cavity

Fluid force and symmetry breaking modes of a 3D bluff body with a base cavity

The Effects of Unsteady On-Road Flow Conditions on Cabin Noise

Flow Angularity Investigations in an Automotive Slotted Wall Wind Tunnel

Contact Info

Product

Resources

About