The paper is devoted to the experimental investigation of the statistical characteristics of the grid-generated turbulence produced in a wind tunnel. Ultrasonic time-of-flight method using dual transducers is utilized to develop a methodology for determination of the correlation functions of turbulent velocity and sound speed fluctuations. The ultrasonic flowmeter equation is considered in the ...

The velocity #uctuations and local strain rate in a #uidized suspension of particles are investigated using the new ultrasonic technique of di!using acoustic wave spectroscopy. DAWS probes the relative motion of the particles at very short length scales down to the inter-particle separation, and allows the spatial correlations of the velocity #uctuations to be probed by varying the transport me...

This paper considers the detection of symmetric crack-like defects in thin metallic plates using longitudinal ultrasonic waves. Only physically small defect sizes are considered in order that the initial stages of crack growth, for example during fatigue, can be detected. This method has the potential to be significantly faster for non-destructively detecting defects than conventional ultrasoni...

The use of power ultrasound refers to the application of sound that is just above the range of human hearing. Under these conditions, an acoustic wave is able to create very high levels of turbulence within an aqueous solution, through the generation of transient cavitation, the growth and violent collapse of microbubbles. Many scientists will be aware of the use of ultrasonic cell disruptors a...

A novel frequency-swept ultrasound-modulated optical tomography technique was developed to image scattering media. A frequency-swept ultrasonic wave was used to modulate the laser light passing through a scattering medium. The modulated light was received by an optical detector and was heterodyned with a reference frequency sweep. The heterodyned signal was recorded in the time domain and was t...

Abstract Recently, multilayer piping has been used widely. Multilayer piping has excellent durability and corrosion resistance. An effective means for quality maintenance of multilayer piping is the laser ultrasonic technique for checking the state of adhesion of the vinyl chloride layer and the steel layer of multilayer piping. The wave is refracted at the interface between the steel layer and...

Lasers can be used to excite and detect ultrasonic waves in a wide variety of materials. This allows the measurement of absolute particle motion without the mechanical disturbances of contacting transducers. In an ultrasound transmission experiment, the wave field is usually accessible only on the boundaries of a sample. Using optical methods, one can measure the surface wave field, in effect, ...

Acoustic wave detection of various underivatized amino acids that were hydrodynamically introduced into and electrokinetically migrated along a capillary tube has been achieved. The detection principle is based on the measurement of the ultrasonic absorption and density change of the aqueous amino acid samples as they pass by the detection zone. Acoustic wave detection of underivatized leucine ...

An elastic wave propagating in a metal loses a portion of its energy from scattering caused by acoustic impedance differences existing at the boundaries of anisotropic grains. Theoretical scattering models capture this phenomena by assuming the incoming wave is described by an average elastic moduli tensorC0 i jkl (x) that is perturbed by a grain with elasticityCi jkl (x ′) where the scattering...

During the last three years the Swedish Institute for Metals Research (SIMR) has done extensive work on applications of laser generated ultrasound (LUS). This paper reports results from several experiments mainly aimed at industrial on-line applications. LUS has been used to determine grain sizes in commercial low-carbon (LC) and stainless steels. The analysis method employs a scattering theory...