A pulsed photoacoustic investigation of ultrasonic mode conversion

1986 ◽  
Vol 64 (9) ◽  
pp. 1334-1340 ◽  
Author(s):  
D. A. Hutchins ◽  
F. Nadeau ◽  
P. Cielo
Keyword(s):  
Nondestructive Testing ◽  
Surface Waves ◽  
Mode Conversion ◽  
Pulsed Laser ◽  
Longitudinal Shear ◽  
Laser Generation ◽  
Bulk Waves ◽  
Interferometric Detection

Experiments have been undertaken into the generation and detection of ultrasonic transients in metals over a 40-MHz bandwidth, using pulsed-laser generation and interferometric detection. Longitudinal, shear, and surface waves have been investigated, and their form compared favorably to theory. The techique has been used to study the interaction of surface and bulk waves with slots in the surface of a plate. It has been shown that significant mode conversion occurred from surface to bulk waves and vice versa. The significance of this result to nondestructive testing is discussed.

scholarly journals The appearance of boundary layers and drift flows due to high-frequency surface waves

2012 ◽  
Vol 707 ◽  
pp. 482-495 ◽  
Author(s):  
Ofer Manor ◽  
Leslie Y. Yeo ◽  
James R. Friend
Keyword(s):  
Boundary Layer ◽  
Surface Waves ◽  
High Frequency ◽  
Slip Boundary Condition ◽  
Inertial Effects ◽  
Velocity Amplitude ◽  
Slip Boundary ◽  
Long Period ◽  
Bulk Waves ◽  
Schlichting Streaming

AbstractThe classical Schlichting boundary layer theory is extended to account for the excitation of generalized surface waves in the frequency and velocity amplitude range commonly used in microfluidic applications, including Rayleigh and Sezawa surface waves and Lamb, flexural and surface-skimming bulk waves. These waves possess longitudinal and transverse displacements of similar magnitude along the boundary, often spatiotemporally out of phase, giving rise to a periodic flow shown to consist of a superposition of classical Schlichting streaming and uniaxial flow that have no net influence on the flow over a long period of time. Correcting the velocity field for weak but significant inertial effects results in a non-vanishing steady component, a drift flow, itself sensitive to both the amplitude and phase (prograde or retrograde) of the surface acoustic wave propagating along the boundary. We validate the proposed theory with experimental observations of colloidal pattern assembly in microchannels filled with dilute particle suspensions to show the complexity of the boundary layer, and suggest an asymptotic slip boundary condition for bulk flow in microfluidic applications that are actuated by surface waves.

Laser generation of narrow‐band surface waves

1992 ◽  
Vol 92 (5) ◽  
pp. 2527-2531 ◽  
Author(s):  
Jin Huang ◽  
Sridhar Krishnaswamy ◽  
Jan D. Achenbach
Keyword(s):  
Surface Waves ◽  
Narrow Band ◽  
Laser Generation

Optimizing Pulsed Laser Holographic Nondestructive Testing

1970 ◽  
Vol 9 (7) ◽  
pp. 1724 ◽  
Author(s):  
C. E. Wiswall ◽  
K. J. Maxwell
Keyword(s):  
Nondestructive Testing ◽  
Pulsed Laser

Remote laser generation of narrow-band surface waves through optical fibers

1999 ◽  
Vol 46 (6) ◽  
pp. 1551-1557 ◽  
Author(s):  
F.L. Di Scalea ◽  
T.P. Berndt ◽  
J.B. Spicer ◽  
B.B. Djordjevic
Keyword(s):  
Surface Waves ◽  
Optical Fibers ◽  
Narrow Band ◽  
Laser Generation

Surface Waves Stimulated by Pulsed Laser Radiation in p-CdTe Crystals

2002 ◽  
Vol 229 (1) ◽  
pp. 177-181 ◽  
Author(s):  
A. Baidullaeva ◽  
A.I. Vlasenko ◽  
P.E. Mozol ◽  
A. Smirnov
Keyword(s):  
Laser Radiation ◽  
Surface Waves ◽  
Pulsed Laser ◽  
Pulsed Laser Radiation

scholarly journals Difficulties with phase spectrum unwrapping in spectral analysis of surface waves nondestructive testing of pavements

1992 ◽  
Vol 29 (3) ◽  
pp. 506-511 ◽  
Author(s):  
M. O. Al-Hunaidi
Keyword(s):  
Spectral Analysis ◽  
Nondestructive Testing ◽  
Surface Waves ◽  
Phase Spectrum ◽  
Correction Procedure ◽  
Near Surface ◽  
Surface Profiling ◽  
Usual Procedure

Spectral analysis of surface waves (SASW) is a nondestructive and in situ method for determining the stiffness profiles of soil and pavement sites. This method involves the generation and measurement of surface Rayleigh waves. By exploiting the dispersive characteristic of these waves in layered systems, the SASW method provides information on the variation of stiffness with depth. This paper presents the results of a case study for near-surface profiling of a pavement site using the SASW method. In this study, inconsistencies were observed in the dispersion curve of the site when the usual procedure of unfolding the relative phase spectrum was followed. A correction procedure to eliminate these inconsistencies is suggested and discussed. The thickness and wave velocities of the various layers obtained with the SASW method, after applying the correction procedure, matched closely those determined from cored samples and cross-hole tests. Key words : nondestructive testing, pavement, layered media, Rayleigh wave, spectral analysis, shear wave velocity, wave propagation.

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