This content is not included in your SAE MOBILUS subscription, or you are not logged in.
The Effect of Free Stream Turbulence on A-pillar Airflow
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 20, 2009 by SAE International in United States
Annotation ability available
Various studies have shown that the level of wind noise experienced inside cars on the road in unsteady conditions can be substantially different from that measured in wind tunnel tests conducted using a low turbulence facility. In this paper a simple geometric body representing the cabin of a passenger car has been used to investigate the effects of free stream turbulence, (FST), on the A-pillar vortex flowfield and the side glass pressure distribution. Beneath the A-pillar vortex, both mean and dynamic pressures are increased by FST. The unsteady pressure can be associated with wind noise and the flow visualization shows the peak unsteadiness is related to the separation of the secondary vortex.
CitationHowell, J., Fuller, J., and Passmore, M., "The Effect of Free Stream Turbulence on A-pillar Airflow," SAE Technical Paper 2009-01-0003, 2009, https://doi.org/10.4271/2009-01-0003.
- Saunders, J.W., Mansour, R.B. ‘On-Road and Wind Tunnel Turbulence and its Measurement Using a Four-Hole Dynamic Probe Ahead of Several Cars’. SAE 2000-01-0350, 2000.
- Gilhome, B.R., Saunders, J.W. ‘The Effect of Turbulence on Peak and Average Pressures on a Car Door’. SAE 2001-01-0253, 2001.
- Lawson, A., Dominy, R., Sheppard, A. ‘A comparison of On-Track and Wind Tunnel Surface Pressure Measurements on a Compact SUV’. SAE 2003-01-0653.
- Lawson, A., Sims-Williams, D.B., Dominy, R. ‘Effects of On-Road Turbulence on Vehicle Surface Pressures in the A-Pillar Region’. SAE 2008-01-0474, 2008.
- Lindener, N., Miehling, H., Cogotti, A., Cogotti, F., Maffei, M. ‘Aeroacoustic Measurements in Turbulent Flow on the Road and in the Wind Tunnel’. SAE 2007-01-1551, 2007.
- Cogotti, A. ‘Generation of a Controlled Level of Turbulence in the Pininfarina Wind Tunnel for the Measurement of Unsteady Aerodynamics and Aeroacoustics’. SAE 2003-01-0430, 2003.
- Watkins, S., Riegel, M., Wiedemann, J. ‘The Effect of Turbulence on Wind Noise’. 4th International Symposium on Automotive and Engine Technology, Stuttgart. Expert-Verlag, ISBN 3-8169-1981-2, 2001.
- Newnham, P.N. ‘The Influence of Real World Turbulence on the Aerodynamic Optimisation of Bluff Body Road Vehicles’. Ph.D. Thesis, Loughborough University, 2007.
- Stapleford, W.R., Carr, G.W. ‘Aerodynamic Noise in Road Vehicles-Parts 1 and 2’. MIRA Reports 1971/2 and 1972/6, 1971-1972.
- Watanabe, M., Harita, M., Hayasa, E. ‘The Effect of Body Shape on Wind Noise’. SAE 780266, 1978.
- Alam, F., Watkins, S., Zimmer, G., Humphris, C. ‘Effects of Vehicle A-pillar Shape on Local Mean and Time-Varying Flow Properties’. SAE 2001-01-1086, 2001.
- Levy, B., Brancher, P., Giovannini, A. ‘Experimental Characterisation of the Velocity and Wall Pressure Fields of an A-Pillar Vortex’. 29th AIAA Aeroacoustics Conference May 2008.
- Johl, G., Passmore, M., Render, P. ‘Design Methodology and Performance of an Indraft Wind Tunnel’. The Aeronautical Journal, Vol. 108, No. 1087, Sept. 2004.
- Newnham, P.N., Passmore, M.A., Howell, J.P., Baxendale, A. ‘On the Optimisation of Road Vehicle Leading Edge Radius in Varying Levels of Freestream Turbulence’. SAE 2006-01-1029, 2006.
- Howell, J., Newnham, P., Passmore, M. ‘Effect of Free Stream Turbulence on Road Vehicle Aerodynamics’. Paper 6, 6th Progress in Vehicle Aerodynamics and Thermal Management, FKFS, University of Stuttgart, October 2007.
- Sims-Williams, D.B., Kaye, S., Watkins, S. ‘Periodic Structures within the Formation Region of Trailing Vortices’. SAE 2006-01-1032, 2006.
- Baden Fuller, J. ‘Measurement of Side Glass Fluctuating Pressures in Varying Onset Turbulence’. Final Year Project, Department of Aeronautical and Automotive Engineering, Loughborough University, 2008.