Topic
Acoustic interferometer
About: Acoustic interferometer is a research topic. Over the lifetime, 1493 publications have been published within this topic receiving 19355 citations.
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Patent•
14 Mar 2016
TL;DR: In this article, an acoustic metamaterial noise control system for HVAC ducts is described, in which the sound waves reflect back to the start of the noise control and also to be absorbed by sound waves within the absorptive core.
Abstract: An acoustic metamaterial noise control system of embodiments of the disclosed technology combines acoustic metamaterial principles with absorptive materials, with a result of a significant reduction in sound radiation within, or emanating from, an HVAC duct. Sound waves that impinge on the noise control system placed at the end (terminal opening of an air duct to ambient space within a room/building), or at a predetermined place on the duct, cause the sound waves to reflect back to the start of the noise control system and also to be absorbed by sound waves within the absorptive core. This is accomplished by way of the use of micro-perforated panels (MPPs) placed in periodic manner with absorptive layers and air gaps to achieve anisotropic conditions to reflect and absorb sound waves for optimum sound reduction.
2 citations
TL;DR: In this article, the cavitation bubble oscillation mode is an asymmetric surface bubble oscillations that does not easily emit ultrasonic waves into water and accumulates acoustic energy from longitudinal waves, which can be used not only for atomization but also for separation of water-ethanol solution.
Abstract: Acoustic cavitation in liquids and capillary waves which cause ultrasonic atomization are considered to be related to the 1/2 subharmonic of ultrasonic surface waves via parametric decay instability. The cavitation bubble oscillation mode is an asymmetric surface bubble oscillation that does not easily emit ultrasonic waves into water and accumulates acoustic energy from longitudinal waves. The capillary waves accumulate acoustic energy in a surface of liquid, enough to be used not only for atomization but also the separation of water‐ethanol solution. These were confirmed by experiments using ultrasonic longitudinal waves in water.
2 citations
Patent•
24 Jun 2015
TL;DR: In this paper, a method of inspecting a pipe for flaws includes emitting ultrasonic waves, controlling the emission of the ultrasonic wave, receiving reflections of the wave, and determining at least one characteristic of one or more flaws.
Abstract: A method of inspecting a pipe for flaws includes emitting ultrasonic waves, controlling the emission of the ultrasonic waves, receiving reflections of the ultrasonic waves, and determining at least one characteristic of one or more flaws. The ultrasonic waves are emitted in a helical pattern through the pipe from an array of ultrasonic transducer elements. The emission of the ultrasonic waves from the array is controlled such that the ultrasonic waves are emitted at a plurality of helical angles within a range of helical angles. The reflections of the ultrasonic waves are caused by impingement of the ultrasonic waves on the one or more flaws. The at least one characteristic of the one or more flaws is determined based on the received reflections of the ultrasonic waves.
2 citations
01 Feb 1970
TL;DR: In this article, a method of readout of elastic surface waves by means of an electron beam is described and the signal detected by the beam is obtained directly in the form of the envelope of an RF pulse at a carrier frequency of 6 MHz.
Abstract: A method of readout of elastic surface waves by means of an electron beam is described. The signal detected by the beam is obtained directly in the form of the envelope of an RF pulse at a carrier frequency of 6 MHz.
2 citations