Acoustic interferometer

About: Acoustic interferometer is a research topic. Over the lifetime, 1493 publications have been published within this topic receiving 19355 citations.

Ultrasonic Measurement of Residual Deformation Stress in Thin Metal Plates Using Surface Acoustic Waves

Abstract: An ultrasonic technique is described for determining stress in 2 flexible stainless steel plates. These plates comprise the variable nozzle of a critical wind tunnel at NASA/Langley Research Center. This technique relates changes in surface acoustic phase velocity t o changes in stress state in the plate. A tracking i nterferometer with resolution of parts in lo7 is used to determine the changes in the acoustic phase velocity as the plate is cycled from flat (stressed) to curved (unstressed), The value of the acoustoelastic constant needed for determination of stress in the flexible plates is obtained by performing a calibration on a plate made of the same material. Potential for further application of this technique in measurement of stress in other such plates is demonstrated.

Observation of sagittal X-ray diffraction by surface acoustic waves in Bragg geometry

Abstract: X-ray Bragg diffraction in sagittal geometry on a Y-cut langasite crystal (La3Ga5SiO14) modulated by Λ = 3 µm Rayleigh surface acoustic waves was studied at the BESSY II synchrotron radiation facility. Owing to the crystal lattice modulation by the surface acoustic wave diffraction, satellites appear. Their intensity and angular separation depend on the amplitude and wavelength of the ultrasonic superlattice. Experimental results are compared with the corresponding theoretical model that exploits the kinematical diffraction theory. This experiment shows that the propagation of the surface acoustic waves creates a dynamical diffraction grating on the crystal surface, and this can be used for space–time modulation of an X-ray beam.

P5G-2 Acoustic Surface Wave Induced Propagation of Liquids in Open Channels

Abstract: The propagation of liquids induced by acoustic streaming turned out to be a successful approach, but applications seem to be restricted to small dimensions of the liquid channel in the order of some tens of micrometers and to piezoelectric substrate materials In this contribution another approach will be described, which allows to extent the dimension of liquid channels to the order of some millimetres or centimetres and allows the use of common structural materials like metals, glass or ceramics as substrates for the propagation of surface acoustic waves: Rayleigh-like waves are excited on the interface of the substrate to the liquid by piezoelectric interdigital transducers attached to the backside of the substrate, from which sound waves are radiated off into the liquid under a characteristic angle determined by the velocities of waves in the liquid and on the substrate, respectively Results of liquid propulsion in open channels obtained with such a set up will be presented, which demonstrate the contributions of different mechanisms of momentum transfer like eg acoustic streaming due to wave propagation along the channel bottom surface, sound absorption in the liquid ("quartz wind") and sound reflection at liquid surfaces

Undergraduate experiment to measure the speed of sound in liquid by diffraction of light

Abstract: Diffraction of light by an ultrasonic phase grating enables a direct measurement of the wavelength of acoustic waves in liquids. If the acoustic frequency is known independently, it can be combined with the measured acoustic wavelength to determine the speed of sound in liquid. The method of Debye and Sears based on a visual display of the diffraction pattern on a distant screen is used. Measurements carried out with a He–Ne laser and an ultrasonic nebulizer provide an excellent experiment for an undergraduate laboratory with a minimum of equipment. A sound velocity of 1536 m/s with an uncertainty of 1% is obtained for distilled water.