The effects of windscreen flow on noise in motorcycle helmets

John Kennedy; Michael Carley; Nigel Holt; Ian Walker

doi:10.1121/1.3646304

The effects of windscreen flow on noise in motorcycle helmets

John Kennedy, Michael Carley, Nigel Holt, Ian Walker

Research output: Contribution to conference › Paper

2 Citations (SciVal)

Abstract

Vortex shedding from a motorcycle windscreen results in three flow regions in which the rider's helmet may be immersed. First, the helmet may be completely in the free stream. Second, it may be in the path of vortex shedding from the windscreen. Third it may be underneath the shed vortices and shielded from the free stream by the windscreen. On-track noise tests were conducted and showed a difference in sound pressure level of more than 10dB and a change in spectra content, due to changes in riding position and helmet angle. Similar tests carried out in a wind tunnel, using simultaneous microphone and flow visualization measurements, allowed the identification of the flow regions. The potential contribution of vortex shedding to the noise was assessed using wavelet analysis to identify intermittent flow structures.

Original language	English
Pages	040005
Number of pages	1
DOIs	https://doi.org/10.1121/1.3646304
Publication status	Published - 15 Sept 2011
Event	161st Acoustical Society of America Meeting - Seattle, WA, USA United States Duration: 23 May 2011 → 27 May 2011

Conference

Conference	161st Acoustical Society of America Meeting
Country/Territory	USA United States
City	Seattle, WA
Period	23/05/11 → 27/05/11

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10.1121/1.3646304

Cite this

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title = "The effects of windscreen flow on noise in motorcycle helmets",

abstract = "Vortex shedding from a motorcycle windscreen results in three flow regions in which the rider's helmet may be immersed. First, the helmet may be completely in the free stream. Second, it may be in the path of vortex shedding from the windscreen. Third it may be underneath the shed vortices and shielded from the free stream by the windscreen. On-track noise tests were conducted and showed a difference in sound pressure level of more than 10dB and a change in spectra content, due to changes in riding position and helmet angle. Similar tests carried out in a wind tunnel, using simultaneous microphone and flow visualization measurements, allowed the identification of the flow regions. The potential contribution of vortex shedding to the noise was assessed using wavelet analysis to identify intermittent flow structures.",

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AU - Kennedy, John

AU - Carley, Michael

AU - Holt, Nigel

AU - Walker, Ian

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N2 - Vortex shedding from a motorcycle windscreen results in three flow regions in which the rider's helmet may be immersed. First, the helmet may be completely in the free stream. Second, it may be in the path of vortex shedding from the windscreen. Third it may be underneath the shed vortices and shielded from the free stream by the windscreen. On-track noise tests were conducted and showed a difference in sound pressure level of more than 10dB and a change in spectra content, due to changes in riding position and helmet angle. Similar tests carried out in a wind tunnel, using simultaneous microphone and flow visualization measurements, allowed the identification of the flow regions. The potential contribution of vortex shedding to the noise was assessed using wavelet analysis to identify intermittent flow structures.

AB - Vortex shedding from a motorcycle windscreen results in three flow regions in which the rider's helmet may be immersed. First, the helmet may be completely in the free stream. Second, it may be in the path of vortex shedding from the windscreen. Third it may be underneath the shed vortices and shielded from the free stream by the windscreen. On-track noise tests were conducted and showed a difference in sound pressure level of more than 10dB and a change in spectra content, due to changes in riding position and helmet angle. Similar tests carried out in a wind tunnel, using simultaneous microphone and flow visualization measurements, allowed the identification of the flow regions. The potential contribution of vortex shedding to the noise was assessed using wavelet analysis to identify intermittent flow structures.

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M3 - Paper

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T2 - 161st Acoustical Society of America Meeting

Y2 - 23 May 2011 through 27 May 2011

ER -

The effects of windscreen flow on noise in motorcycle helmets

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