Acoustic particle velocity horns

Abstract

The paper considers receiving acoustic horns designed for particle velocity amplification and suitable for use in vector sensing applications. Unlike conventional horns, designed for acoustic pressure amplification, acoustic velocity horns (AVHs) deliver significant velocity amplification even when the overall size of the horn is much less than an acoustic wavelength. An AVH requires an open-ended configuration, as compared to pressure horns which are terminated at the throat. The appropriate formulation, based on Webster's one-dimensional horn equation, is derived and analyzed for single conical and exponential horns as well as for double-horn configurations. Predicted horn amplification factors (ratio of mouth-to-throat radii) were verified using numerical modeling. It is shown that three independent geometrical parameters principally control a horn's performance: length l, throat radius R(1), and flare rate. Below a predicted resonance region, velocity amplification is practically independent of frequency. Acoustic velocity horns are naturally directional, providing maximum velocity amplification along the boresight.

Monaural Sound Localization Based on Structure-Induced Acoustic Resonance

“…The previous section presents the mathematical model for the discrete conical horn by Donskoy and Cray [30] and verifies the existence of the fundamental frequency by showing the spectral plots. Above the linear combination of the horns, the ML structure shows an additional relationship that is investigated in this section.…”

“…Equation (5) provides the mathematical model between the fundamental frequency and cylindrical pipe [29] and Donskoy & Cray calculate the model for a conical horn [30]. Both equations cannot be applied directly to the ML structure because of the discordance of shape parameters.…”

“…We note that a derivation of the model is not the object of this paper; hence, the conventional conical horn model is instead adapted for the structure analysis. Recently, Donskoy and Cray developed a mathematical model for receiving acoustic horns including a conical horn in order to achieve velocity amplification [30]. The paper presented the following equation for a sound pressure amplification factor that is the ratio between the sound pressure at throat P 1 and unperturbed medium P 0 .…”

Design and Optimization of Sensitivity Enhancement Package for MEMS-Based Thermal Acoustic Particle Velocity Sensor

“…Later, Stuart derived the solutions of exponential, parabolic, and hyperbolic horns from Webster’s horn equation [ 31 ]. Donskoy et al derived the formulation of double cone horn from Webster’s horn equation and verified the horn amplification factors using numerical modeling [ 32 , 33 , 34 ]. Honschoten et al analyzed the double cylinder horn both analytically and by means of finite volume simulations on fluid dynamics [ 35 ].…”

Characterization of gain and directivity of exponential horn receivers

“…Historically in the early age of microphone technology, the horn as a receiver had been considered to overcome the self-noise of the microphone and amplifier. 17 While this mode of operation persists in biological systems, with few exceptions 18 the horn as a receiver has fallen out of interest because advancements in electrical technology have made equipment that is suitable for most applications widely available. Furthermore, given the size of conventional microphone diaphragms, horns must be very large to achieve any benefit.…”