Sound Propagation over Flat Ground with an Impedance Discontinuity

Sound propagation over screened ground under upwind conditions

Sound propagation over soft ground without and with crops and potential for surface transport noise attenuation.

Growing demand on transportation, road, and railway networks has resulted in increased levels of annoyance from road traffic. Optimized use of green surfaces in combination with vegetation may be desirable as a method for reducing the noise impact of road traffic in urban and rural environments. Sound propagation over soft ground and through crops has been studied through outdoor measurements a...

Excess attenuation for sound propagation over an urban canyon

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Propagation of Waves in a Bifurcated Cylindrical Waveguide with Wall Impedance Discontinuity

In the present work the radiation of sound from a bifurcated circular waveguide formed by a semi-infinite rigid duct inserted axially into a larger infinite tube with discontinuous wall impedance is reconsidered through an alternative approach which consists of using the mode matching technique in conjunction with the Wiener-Hopf method. By expressing the total field in the appropriate waveguid...

Simulation of sound propagation over porous barriers of arbitrary shapes.

A time-domain solver using an immersed boundary method is investigated for simulating sound propagation over porous and rigid barriers of arbitrary shapes. In this study, acoustic propagation in the air from an impulse source over the ground is considered as a model problem. The linearized Euler equations are solved for sound propagation in the air and the Zwikker-Kosten equations for propagati...