Evolution of performance of an automotive wind tunnel

Cogotti, A.

doi:10.1016/j.jweia.2007.06.007

Cited by 22 publications

(13 citation statements)

References 21 publications

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“…The tunnel is of closed-return type with an open jet test section and its nozzle area is of 11 m 2 with a contraction ratio of 6.9:1 [18]. A cross-sectional view of the wind tunnel is shown in Figure 2.…”

Section: Pininfarina Wind Tunnelmentioning

confidence: 99%

“…The ambient noise in the test section has been progressively reduced with a reported test section (out-of-flow) background noise level of 68 dBA at 100 km/h. Facility details related to aeroacoustics are available in [18,25,26]. This tunnel includes the capability to create elevated turbulence levels with relatively long length scales through a pioneering active "Turbulence Generation System" (TGS).…”

Section: Pininfarina Wind Tunnelmentioning

confidence: 99%

“…: as discussed by [13,17]) and aerodynamic noise has tended to grow in importance as other sources of noise have been better attenuated in modern vehicles. Various researchers including [18,19,20,21] discussed that broadband noise sources which normally dominate the passenger compartment are related to A-pillar vortex flow or separated flows on the side or rear of the vehicle. These usually occur at mid and high frequencies and, as dipole sources, they approximately scale with velocity to the power of 6 (e.g.…”

Section: Introductionmentioning

confidence: 99%

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The Effects of Unsteady Flow Conditions on Vehicle in Cabin and External Noise Generation

Kounenis¹,

Sims-Williams²,

Dominy³

et al. 2015

SAE Technical Paper Series

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Citation for published item:uounenisD ghrlmpos nd imsEillimsD hvid nd hominyD oert nd fersonD ergnth¤ el nd yettleD xihols nd preemnD glire @PHISA 9he e'ets of unstedy )ow onditions on vehile in in nd externl noise genertionF9D ei tehnil pper seriesF F PHISEHIEISSSF Further information on publisher's website: httpsXGGdoiForgGIHFRPUIGPHISEHIEISSS Publisher's copyright statement:Copyright c 2015 SAE International. This paper is posted on this site with permission from SAE International. It may not be shared, downloaded, duplicated, printed or transmitted in any manner, or stored on any additional repositories or retrieval system without prior written permission from SAE. Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractA vehicle driving on the road experiences unsteady flow conditions which are not generally reproduced in the development environment. This paper investigates the potential importance of this difference to aeroacoustics and hence to occupant perception and proposes a methodology to enable better ranking of designs by taking account of wind noise modulation.Two approaches of reproducing the effects of unsteady wind on aeroacoustics were investigated: an active wind tunnel Turbulence Generation System (TGS) and a quasi-steady approach based on measurements at a series of fixed yaw angles. A number of tools were used to investigate the onset flow and its impacts, including roofmounted probe, acoustic heads and surface microphones. External noise measurements help to reveal the response of separate exterior noise sources to yaw.The noise experienced by the driver or passenger ear facing the side-glass is dominated by increased sound pressure levels when the adjacent side-glass is the leeward side of the vehicle with some non-linear effects as leeward yaw produces first accelerated flow and then separation.In part because of non-linearity in response to yaw, a challenging parameter for a wind tunnel simulation of dynamic yaw is achieving a wide enough variation in yaw angle and this work suggests that considering an appropriate range of yaw angles is more important than capturing the dynamics.In terms of passenger perception, the most important effect of a time-varying onset flow was demonstrated to be the modulation of wind noise rather than the increase in time-averaged cabin noise. For the case considered, at 130 km/h, the impact of wind-noise modulation was found to be equivalent to an extra 1-2 dBA in terms of passenger perception, while the increment in time-averaged cabin noise w...

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Section: Pininfarina Wind Tunnelmentioning

confidence: 99%

Section: Pininfarina Wind Tunnelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Effects of Unsteady Flow Conditions on Vehicle in Cabin and External Noise Generation

Kounenis¹,

Sims-Williams²,

Dominy³

et al. 2015

SAE Technical Paper Series

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“…Hyun Wook Han 1) ․Hyun Ho Park 1) ․Moon Sang Kim *1) ․Jong Paek Ha 2) ․Yong Nyun Kim (Fig. 21), OSRVM의 항력 변화의 폭은 10N 이내임을 보이고 있다 (Fig.…”

Section: Aerodynamic Performance Dependency On the Geometric Shape Anunclassified

Aerodynamic Performance Dependency on the Geometric Shape and Mounting Location of OSRVM

Han¹,

Park²,

Kim³

et al. 2013

Transactions of the Korean Society of Automotive Engineers

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: This study investigates the effects of OSRVM mounting location and its configurations such as stalk height and housing height on the aerodynamic performance of the passenger car. In order to validate the flow solver, FLUENT which is very well known commercial code, the flow field around an Ahmed Body was analyzed numerically and compared with the experimental data. The predicted aerodynamic performance and flow patterns around a car show good agreements with the experimental data. Mounting location and stalk height should be designed while OSRVM is mounted on the car to evaluate the aerodynamic performance precisely. Housing height, however, may be designed independent of the car because the aerodynamic interference between housing height and car configuration is negligible.

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“…The experimental part is usually carried out in a wind tunnel, where a vehicle is placed on a set of balances in a closed chamber, while a fan provides the necessary airflow. Here the focus is again very much on simulating body motions and correct underbody flow, but also on making the freestream airflow as similar to real world conditions as possible by using turbulence or cross wind generation systems [1]. Regarding the underbody flow, it is now more or less common practice to use a central moving belt on the floor and wheel drive units which allow for wheel rotation to ensure better correlation with on-road conditions.…”

Section: Introductionmentioning

confidence: 99%

Vehicle Ride Height Change Due To Radial Expansion Of Tires

Čavoj¹,

Blaťák²,

Hejtmánek³

et al. 2015

Journal of Middle European Construction and Design of Cars

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In general, tire deformations caused by wheel rotation are not taken into account when developing vehicle aerodynamics. On the road the tires radially expand as speed increases, which affects the actual ride height of a vehicle. In turn this often increases the real aerodynamic drag compared to values obtained using CFD or a wind tunnel as the mass flow across the relatively rough underbody increases with ground clearance. In this study, on-road ride heights were measured while running a vehicle in a straight line with fixed velocity whilst the aerodynamic lift of the vehicle was determined in a wind tunnel. Subsequently, the relationships between ride height and axle load were obtained by loading the vehicle at standstill with ballast. By comparing the ride heights at high and very low velocities with expected vertical displacement caused purely by aerodynamic lift force as computed according to the ride height -axle load equations, the ride height change due to tire radial expansion was determined.

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Evolution of performance of an automotive wind tunnel

Cited by 22 publications

References 21 publications

The Effects of Unsteady Flow Conditions on Vehicle in Cabin and External Noise Generation

The Effects of Unsteady Flow Conditions on Vehicle in Cabin and External Noise Generation

Aerodynamic Performance Dependency on the Geometric Shape and Mounting Location of OSRVM

Vehicle Ride Height Change Due To Radial Expansion Of Tires

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