Transient, planar, nonlinear acoustical holography for reconstructing acoustic pressure and particle velocity fields

2013 ◽  
Vol 134 (5) ◽  
pp. 3980-3980
Author(s):  
Yaying Niu ◽  
Zheyu Zha ◽  
Yong-Joe Kim
Keyword(s):  
Particle Velocity ◽  
Acoustic Pressure ◽  
Velocity Fields ◽  
Acoustical Holography

scholarly journals Numerical Modelling of the Ultrasonic Treatment of Aluminium Melts: An Overview of Recent Advances

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3262 ◽  
Author(s):  
Bruno Lebon ◽  
Iakovos Tzanakis ◽  
Koulis Pericleous ◽  
Dmitry Eskin
Keyword(s):  
Best Practice ◽  
Acoustic Pressure ◽  
Pressure Field ◽  
State Of The Art ◽  
Liquid Metals ◽  
Numerical Models ◽  
Acoustic Cavitation ◽  
Velocity Fields ◽  
Melt Processing ◽  
Best Practice Guidelines

The prediction of the acoustic pressure field and associated streaming is of paramount importance to ultrasonic melt processing. Hence, the last decade has witnessed the emergence of various numerical models for predicting acoustic pressures and velocity fields in liquid metals subject to ultrasonic excitation at large amplitudes. This paper summarizes recent research, arguably the state of the art, and suggests best practice guidelines in acoustic cavitation modelling as applied to aluminium melts. We also present the remaining challenges that are to be addressed to pave the way for a reliable and complete working numerical package that can assist in scaling up this promising technology.

scholarly journals Geoacoustic inversion based on both acoustic pressure and particle velocity

2006 ◽  
Vol 120 (5) ◽  
pp. 3355-3356
Author(s):  
A. Vincent van Leijen ◽  
Jean‐Pierre Hermand ◽  
Kevin B. Smith
Keyword(s):  
Particle Velocity ◽  
Acoustic Pressure ◽  
Geoacoustic Inversion

scholarly journals On the use of acoustic particle velocity fields in adjoint‐based inversion

2006 ◽  
Vol 120 (5) ◽  
pp. 3356-3356
Author(s):  
Matthias Meyer ◽  
Jean‐Pierre Hermand ◽  
Kevin B. Smith
Keyword(s):  
Particle Velocity ◽  
Velocity Fields

scholarly journals Acoustic Pressure and Particle Velocity for Spatial Filtering of Bottom Arrivals

2019 ◽  
Vol 44 (1) ◽  
pp. 179-192 ◽  
Author(s):  
Paulo Felisberto ◽  
Paulo Santos ◽  
Sergio M. Jesus
Keyword(s):  
Particle Velocity ◽  
Acoustic Pressure ◽  
Spatial Filtering

Flow-Excited Acoustic Resonance of Isolated Cylinders in Cross-Flow

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Nadim Arafa ◽  
Atef Mohany
Keyword(s):  
Particle Velocity ◽  
Acoustic Pressure ◽  
Excited Level ◽  
Cross Flow ◽  
Acoustic Resonance ◽  
Excitation Level ◽  
Linear Superposition ◽  
The Cross ◽  
Particle Velocities ◽  
Mode A

The flow-excited acoustic resonance of isolated cylinders in cross-flow is investigated experimentally where the effect of the cylinder(s) proximity to the acoustic particle velocity nodes of the cross-modes is presented in this paper. For the case of a single cylinder, the cylinder's location does not significantly affect the vortex shedding process; however, it affects the excitation level of each acoustic cross-mode. When the cylinder is moved away from the acoustic particle velocity antinode of a specific acoustic cross-mode, a combination of the cross-modes is excited with intensities that seem to be proportional to the ratio of the acoustic particle velocities of these modes at the cylinder's location. For the cases of two and three hydrodynamically uncoupled cylinders positioned simultaneously side-by-side in the duct, it is observed that the first three acoustic cross-modes are excited. When one cylinder is positioned at the acoustic particle velocity antinode of a specific cross-mode and another cylinder is positioned at its acoustic particle velocity node, i.e., a cylinder that should excite the resonance and another one that should not excite it, respectively; the excitation always takes over and the resonance occurs at a further elevated levels. It is also observed that the acoustic pressure levels in the cases of multiple cylinders are not resulting from a linear superposition of the excited level obtained from each individual cylinder which indicates that the removal of cylinders at certain locations may not be a viable technique to eliminate the acoustic resonance in the case of tube bundles.

Ultrasonic Measurements of Local Particle Velocity and Concentration Within the Casing of a Centrifugal Pump

2015 ◽  
Author(s):  
John M. Furlan ◽  
Mohamed Garman ◽  
Jaikrishnan Kadambi ◽  
Robert J. Visintainer ◽  
Krishnan V. Pagalthivarthi
Keyword(s):  
Centrifugal Pump ◽  
Particle Velocity ◽  
Volume Fraction ◽  
Side Wall ◽  
Velocity Fields ◽  
Solid Particles ◽  
Acoustic Properties ◽  
Soda Lime Glass ◽  
Calibration Data ◽  
Slurry Flows

In the design of slurry transport equipment used in the mining and dredging industries, the effects of solid particle velocity and concentration on hydraulic performance and wear need to be considered. Two ultrasonic techniques have been used to investigate slurry flows through a centrifugal pump casing: a local particle concentration measurement technique (Furlan et al., 2012) and a pulsed ultrasonic Doppler Velocimetry (PUDV) technique (Hanjiang, 2003, Garman, 2015). Local particle velocities and concentrations have been obtained in a flow of soda lime glass particles (diameter of 195 μm) and water through the casing of a centrifugal slurry pump operating close to the best efficiency point using the two ultrasound techniques. For the concentration measurements, the acoustic properties of slurry flows such as sonic velocity, backscatter, and attenuation are correlated to the volume fraction of solid particles. The algorithm utilizes measurements obtained from homogeneous vertical pipe flow fields as calibration data in order to obtain experimental concentration profiles in the non-homogenous flow regimes which are encountered in the pump casing. The PUDV technique correlates the Doppler shift in frequency associated with the movement of particles towards or away from the transducer. A two measurement (angle) technique is applied within the pump casing in order to account for the components of particle velocity which are orthogonal to the casing side wall. The techniques are utilized to obtain concentration and velocity profiles within the pump casing for overall average loop particle concentrations ranging from 7–11 % by volume. The experimental results are compared with the concentration and velocity fields that are predicted by in-house finite element computational fluid dynamics (CFD) codes (Pagalthivarthi and Visintainer, 2009) which are used to predict wear in centrifugal slurry pump wet end components. Reasonable agreement is observed for both the concentration and velocity fields. Specifically, measurements indicate that there is a reduction of in-situ concentration and hence a corresponding radial acceleration of the particles with respect to the fluid occurring within the impeller which has also been predicted by computational predictions of flow through the impeller (Pagalthivarthi et al., 2013). Additionally, the prediction of the existence of secondary flow patterns by the casing computational code has been supported with the velocity measurements.

Resonance of Trapped Acoustic Modes of a Ducted Rectangular Cavity

2015 ◽  
Author(s):  
Michael Bolduc ◽  
Samir Ziada ◽  
Philippe Lafon
Keyword(s):  
Shear Layer ◽  
Particle Velocity ◽  
Acoustic Mode ◽  
Velocity Fields ◽  
Mode Shapes ◽  
Test Results ◽  
Trapped Modes ◽  
Cross Sectional ◽  
Acoustic Modes ◽  
Axisymmetric Cavities

Flow over ducted cavities can lead to strong resonances of the trapped acoustic modes due to the presence of the cavity within the duct. Aly & Ziada [1–3] investigated the excitation mechanism of acoustic trapped modes in axisymmetric cavities. These trapped modes in axisymmetric cavities tend to spin because they do not have preferred orientation. The present paper investigates rectangular cross-sectional cavities as this cavity geometry introduces an orientation preference to the excited acoustic mode. Three cavities are investigated, one of which is square while the other two are rectangular. In each case, numerical simulations are performed to characterize the acoustic mode shapes and the associated acoustic particle velocity fields. The test results show the existence of stationary modes, being excited either consecutively or simultaneously, and a particular spinning mode for the cavity with square cross-section. The computed acoustic pressure and particle velocity fields of the excited modes suggest complex oscillation patterns of the cavity shear layer because it is excited, at the upstream corner, by periodic distributions of the particle velocity along the shear layer circumference.

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