Generation and propagation of shock waves in the exhaust pipe of a 4 cycle automobile engine

Sekine, Noriaki; Matsumura, Shuji; Aoki, K.; Takayama, K.

doi:10.1063/1.39502

Cited by 14 publications

(12 citation statements)

References 3 publications

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“…If the mass flux discharged is sufficiently large, the pulse jet leads to a strong impulse wave which propagates toward surroundings. Similar flows are made by the discharge of a shock wave from the exit of a duct, leading to an impulse wave that is usually characterized by a high peak pressure of short duration [1][2][3]. Com-pared with the noise of a subsonic or a supersonic steady jet discharged from a nozzle or orifice [4,5], the noise due to such an impulse wave often causes large, undesirable, unsteady loads and pressure transients which are a major source of structural vibration and fatigue of a mechanical system.…”

Section: Introductionmentioning

confidence: 99%

Effect of duct geometry on shock wave discharge

et al. 2006

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This paper describes computational work to understand the unsteady flow-field of a shock wave discharging from an exit of a duct and impinging upon a flat plate. A flat plate is located downstream, and normal to the axis of the duct. The distance between the exit of the duct and flat plate is changed. In the present study, two different duct geometries (i.e., square and cross section) are simulated to investigate the effect of duct geometry on the un-steady flows of a shock wave. In computation, the total variation diminishing (TVD) scheme is employed to solve three-dimensional, unsteady, compressible, Euler equations. Computations are performed over the range of shock Mach number from 1.05 to 1.75. Computational results can predict the three-dimensional dynamic behaviour of the shock wave impinging upon the flat plate. The results obtained show that the pressure increase generated on the plate by the shock impingement depends on the duct geometry and the distance between the duct exit and plate, as well as the shock Mach number. It is also found that for the duct with cross-section, the unsteady loads acting on the flat plate are less, compared with the square duct.

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Section: Introductionmentioning

confidence: 99%

Effect of duct geometry on shock wave discharge

et al. 2006

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“…Such impulse waves are encountered in a variety of unsteady internal #ow devices, such as gun muzzles [4], internal combustion engine exhaust mu%ers [5], high-speed railway tunnels [6], etc. In these applications, the impulse waves often cause annoying noises as well as pressure transients, which give rise to undesirable unsteady loads and structural vibrations.…”

Section: Introductionmentioning

confidence: 99%

Study of the Impingement of Impulse Wave Upon a Flat Plate

Setoguchi

Kim²,

Kashimura

2002

Journal of Sound and Vibration

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“…Both the shock waves and the induced high-speed flow are employed for research not only in aerospace engineering (Viren et al, 2005) but also into industrial issues, such as the exhaust noise generated by automobile's engines (Sekine et al, 1990). Several experiments have been carried out to evaluate the strength of noise produced by a single-stage powder gun, which assumed that the shock-wave-induced, high-speed flow generated at the open end of a shock tube behaves similar to the combustion gas emerging from the gun (Phan and Hurdle, 1990).…”

Section: Introductionmentioning

confidence: 99%

Visualization and force measurement of high-temperature, supersonic impulse jet impinging on baffle plate

Mizukaki

2007

J Vis

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The flow visualization and force measurement of a supersonic impinging jet on a center-holed vertical baffle plate were investigated. Center-holed baffle plates of 2d to 5d in diameter, with a 1d center hole were tested, where d is the bore of the launch tube. The standoff distance of the baffle plates from the open end of the launch tube were varied to be from 2d to 5d. The supersonic impulse jet, with an incident shock wave of Mach 2.89 was produced by a high-enthalpy blast-wave simulator. The direction-indicating color schlieren method produced a two-dimensional density gradient of the flow field around the baffle plate. In addition, the flow fields were numerically analyzed, using two-dimensional asymmetric Euler equations. The results of the numerically-analyzed and the experimentally-visualized flow field agreed well. The visualized flow field indicates that the baffle plate should be at least 3.5d in diameter to deflect the supersonic impinging jet at an angle greater than a right angle. We have concluded that the representative method of designing muzzle brakes for military purpose accurately predicts the force yielded by the supersonic impinging impulse jet on the vertical baffle plate only when there is a large ratio of the baffle-plate diameter to the bore of the launch tube.

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Generation and propagation of shock waves in the exhaust pipe of a 4 cycle automobile engine

Cited by 14 publications

References 3 publications

Effect of duct geometry on shock wave discharge

Effect of duct geometry on shock wave discharge

Study of the Impingement of Impulse Wave Upon a Flat Plate

Visualization and force measurement of high-temperature, supersonic impulse jet impinging on baffle plate

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