CFD Simulation of Side Glass Surface Noise Spectra for a Bluff SUV

Gaylard, Adrian

doi:10.4271/2006-01-0137

Cited by 29 publications

(3 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The trace of the streamlines confirms that the separation and reattachment points observed in the cross-sections of the A-pillar vortex analysed in Levy and Brancher (2013) correspond to separation and reattachment lines extending along the side wall. This is in agreement with past studies on real road vehicles (Haruna et al, 1990;Gaylard, 2007), which justifies the relevance of the 301 dihedron as a generic model to reproduce the A-pillar vortex flow.…”

Section: Wall Flowsupporting

confidence: 92%

Experimental investigation of the wall dynamics of the A-pillar vortex flow

Levy

Brancher

2015

Journal of Fluids and Structures

View full text Add to dashboard Cite

The influence of the A-pillar vortex on the wall flow of the side window of a car is investigated experimentally using a 301 dihedron model. The measurement of the unsteady pressure at the wall provides a map of the pressure fluctuation intensity, and a spectral analysis is performed to track the dominant frequencies of the wall pressure fluctuations. The wall flow generated by the vortex structure that develops parallel to the side-wall is characterised by means of particle image velocimetry (PIV). Its structure is analysed and compared to cross-sections of the A-pillar vortex in order to identify the different separation and reattachment lines. A comparison of the field of turbulent kinetic energy obtained by PIV with the map of the pressure fluctuations shows a correlation between the structure of the A-pillar vortex and the pressure fluctuations. It is found that the dominant wall pressure fluctuations are located at the secondary separation line, whereas the primary reattachment line does not show any significant pressure variations, that the A-pillar vortex will not naturally break down and that discrete vortices may be associated with the pressure fluctuations.

show abstract

Section: Wall Flowsupporting

confidence: 92%

Experimental investigation of the wall dynamics of the A-pillar vortex flow

Levy

Brancher

2015

Journal of Fluids and Structures

View full text Add to dashboard Cite

show abstract

“…A number of numerical studies have been completed investigating noise generation of the A-pillar region. Gaylard (2006) investigated the solution accuracy of a Lattice Boltzmann solver. It was found that this method tended to over-predict the size of the A-pillar vortex, whilst a RANS solver tended to under-predict.…”

Section: Introduction and Aimsmentioning

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

“…30 Furthermore, the flow may accelerate through the gap between the door mirror head and the side glass. 31 The windscreen surface flow, A-pillar vortex, door mirror wake and the action of the wiper system all influence the distribution of water over this region. Rain and spray hitting the windscreen is forced towards the A-pillars by the periodic action of the windscreen wipers and the aerodynamic shear.…”

Section: Exterior Water Managementmentioning

confidence: 99%

Surface contamination of cars: A review

Gaylard

Kirwan

Lockerby

2017

Proceedings of the Institution of Mechanical Engineers, Part D:

View full text Add to dashboard Cite

This review surveys the problem of surface contamination of cars, which poses a growing engineering challenge to vehicle manufacturers, operators and users. Both the vision of drivers and the visibility of vehicles need to be maintained under a wide range of environmental conditions. This requires managing the flow of surface water on windscreens and side glazing. The rate of deposition of solid contaminants on glazing, lights, licence plates and external mirrors also needs to be minimised. Maintaining vehicle aesthetics and limiting the transfer of contaminants to the hands and clothes of users from soiled surfaces are also significant issues. Recently, keeping camera lenses clean has emerged as a key concern, as these systems transition from occasional manoeuvring aids to sensors for safety systems. The deposition of water and solid contaminants on to car surfaces is strongly influenced by unsteady vehicle aerodynamic effects. Airborne water droplets falling as rain or lifted as spray by tyres interact with wakes, vortices and shear flows and accumulate on vehicle surfaces as a consequence. The same aerodynamic effects also control the movement of surface water droplets, rivulets and films; hence, particular attention is paid to the management of surface water over the front side glass and the deposition of contaminants on the rear surfaces. The test methods used in the automotive industry are reviewed, as are the numerical simulation techniques.

show abstract

CFD Simulation of Side Glass Surface Noise Spectra for a Bluff SUV

Cited by 29 publications

References 9 publications

Experimental investigation of the wall dynamics of the A-pillar vortex flow

Experimental investigation of the wall dynamics of the A-pillar vortex flow

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

Surface contamination of cars: A review

Contact Info

Product

Resources

About