Identification of Tire Noise Generation Mechanisms Using a Roadwheel Facility

Plotkin, Kenneth J.; Montroll, Mark M.; Fuller, William R.; Nozick, Harvey J.

doi:10.4271/800281

Cited by 4 publications

(3 citation statements)

References 3 publications

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“…Fig. 14 of Plotkin 1979 shows that monopole theory correctly predicts acoustic intensities when volume changes are approximately simple harmonic and provides poor predictions otherwise.…”

Section: Monopole Theorymentioning

confidence: 99%

Nonlinear Acoustic Sources in Squeezed Car Tyre Cavities

Gagen

2000

Noise & Vibration Worldwide

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At high speeds, the grooves cut into car tire treads can be rapidly squeezed and suffer volume losses of around 10%. This decrease in groove volume can occur much faster than air can evacuate from the squeezed groove as ground impact causes the groove walls to move with velocities of order 1m/s, and with accelerations of 103m/s2 over time scales of about 1ms. The resulting volume loss without any accompanying evacuation of air leads to significant increases in pressure and density in the groove. The pressure fluctuations can exceed 10% of ambient conditions which makes the usual approximations underlying use of the acoustic wave equation invalid. The acoustic wave equation can only be used when pressure fluctuations and pressure gradients are small. When substantial pressure fluctuations exist or when shock waves are present the usual acoustic wave equation cannot be used and a fuller treatment is required. This paper presents preliminary analytical and numerical investigations of the various nonlinear effects which might create novel acoustic sources from squeezed cavities in car tires.

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“…Fig. 14 of Plotkin 1979 shows that monopole theory correctly predicts acoustic intensities when volume changes are approximately simple harmonic and provides poor predictions otherwise.…”

Section: Monopole Theorymentioning

confidence: 99%

Nonlinear Acoustic Sources in Squeezed Car Tyre Cavities

Gagen

2000

Noise & Vibration Worldwide

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“…Therefore, the sound pressure of equation (1) must be reduced by the factor two, as stated in reference [10].…”

Section: Analysis Of the Leading Edge Recordingsmentioning

confidence: 99%

Air-related mechanisms of noise generation by solid rubber tyres with cavities

2010

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There are four main air-related noise generation mechanisms at the tyre/road interface, which were all categorised more than 20 years ago. The first one is the so-called 'air pumping' mechanism. Two other air-related phenomena that occur when there are air movements near the contact patch of the tyre are 'air resonant radiation' and 'pipe S.J.Walsh@lboro.ac.uk 2 resonances' which appear at the footprint of the tyre. In addition to these, there is a forth effect, which is mentioned in the literature, that is occurring due to turbulence effects of the air surrounding the spinning tyre. There has been less focus on the air related mechanisms than on other types of tyre noise generation mechanisms. This paper attempts to add some detail to current understanding of the air-related noise generation at the tyre road interface and gives some further information on how to identify the differences due to these mechanisms. Specifically in the present paper, a solid rubber tyre running on a vehicle chassis dynamometer is used to study the first two mechanisms. This is done with emphasis on the time history of the recorded signal and not on the frequency spectrum, as is more commonly used. A comparison with existing theoretical models of these mechanisms reveals some of the strength and weaknesses of the current understanding of these phenomena.

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“…When volume changes depart from being sinusoidal the fit between theory and experiment is not so good. 3 Air pumping noise sources occur as air moves into and out of tire cavities as the tire tread contacts the road and have been modeled by treating the squeezed cavity as an organ pipe with one end closed so as to sustain a /4 resonance. This approach models the air as a piston moving backwards and forwards on a spring.…”

Section: Introductionmentioning

confidence: 99%

Novel acoustic sources from squeezed cavities in car tires

Gagen

1999

The Journal of the Acoustical Society of America

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This paper demonstrates that the partial squeezing of car tire cavities at ground impact cannot be adequately modeled by the usual acoustic wave equation. A more complete treatment must begin with the Euler equations for fluid flow in a squeezed cavity to derive a wave equation dependent on cavity wall velocities and accelerations. These can be sizable as ground impact causes the walls of a tire cavity to move with velocities of order 1 m/s and with accelerations of 10 3 m/s 2 over time scales of about 1 ms. Further, the geometry of a typical cavity is such that width compression causes significant increases in pressure and density to occur before the arrival of the rarefaction wave propagating from the open end of the cavity begins to exhaust the full length of the cavity. This causes significant departures from equilibrium density and pressure conditions. These influences are demonstrated both analytically and numerically.

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Identification of Tire Noise Generation Mechanisms Using a Roadwheel Facility

Cited by 4 publications

References 3 publications

Nonlinear Acoustic Sources in Squeezed Car Tyre Cavities

Nonlinear Acoustic Sources in Squeezed Car Tyre Cavities

Air-related mechanisms of noise generation by solid rubber tyres with cavities

Novel acoustic sources from squeezed cavities in car tires

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