Experimental investigation of wave fields produced by sources of longitudinal and shear waves

1966 ◽  
Vol 10 (3) ◽  
pp. 387-396 ◽  
Author(s):  
Vladimír Schenk
Keyword(s):  
Experimental Investigation ◽  
Shear Waves ◽  
Wave Fields ◽  
Longitudinal And Shear Waves

scholarly journals An Experimental Investigation of Internal Tide Generation by Two-Dimensional Topography

2008 ◽  
Vol 38 (1) ◽  
pp. 235-242 ◽  
Author(s):  
Thomas Peacock ◽  
Paula Echeverri ◽  
Neil J. Balmforth
Keyword(s):  
Experimental Investigation ◽  
Wave Field ◽  
Internal Tide ◽  
Two Dimensional ◽  
Knife Edge ◽  
Wave Fields ◽  
Schlieren Technique ◽  
Conversion Rates ◽  
Theoretical Predictions ◽  
Secondary Instabilities

Abstract Experimental results of internal tide generation by two-dimensional topography are presented. The synthetic Schlieren technique is used to study the wave fields generated by a Gaussian bump and a knife edge. The data compare well to theoretical predictions, supporting the use of these models to predict tidal conversion rates. In the experiments, viscosity plays an important role in smoothing the wave fields, which heals the singularities that can appear in inviscid theory and suppresses secondary instabilities of the experimental wave field.

Preliminary results of an investigation of crustal structure in Southeastern Europe

1966 ◽  
Vol 56 (6) ◽  
pp. 1241-1268
Author(s):  
Basil C. Papazachos ◽  
Peter E. Comninakis ◽  
John C. Drakopoulos
Keyword(s):  
Travel Time ◽  
Crustal Structure ◽  
Lower Layer ◽  
Shear Waves ◽  
Middle Layer ◽  
Average Thickness ◽  
Southeastern Europe ◽  
Preliminary Results ◽  
Longitudinal And Shear Waves ◽  
Layered Crust

Abstract Travel-time curves for the most prominent phases of the longitudinal and shear waves for epicentral distances between zero and 140 km and between 200 km and 1000 km have been constructed for Southeastern Europe. Both refraction and reflection methods indicate a three-layered crust. The average thickness is approximately 16 km for the top layer, 15 for the middle layer and 11 for the lower layer. The crustal thickness varies from about 47 to 32 km from place to place. The extremely low value 0.21 for Poisson's ratio was found in the top as well as in the middle layer.

Estimation of Local Elastic Moduli of Carbon-Containing Materials by Laser Ultrasound

2018 ◽  
Vol 769 ◽  
pp. 96-101 ◽  
Author(s):  
Ivan A. Shibaev ◽  
Dmitry V. Morozov ◽  
Oleg L. Dudchenko ◽  
Ilya A. Pavlov
Keyword(s):  
Chemical Composition ◽  
Shear Modulus ◽  
Elastic Properties ◽  
Precision Measurement ◽  
Elastic Moduli ◽  
Pyrolytic Graphite ◽  
Shear Waves ◽  
Laser Ultrasound ◽  
Longitudinal And Shear Waves ◽  
Ultrasonic Techniques

The elastic properties of two carbon-containing materials are investigated. Shungite rock is a natural nanocomposite; isotropic pyrolytic graphite is an artificial material. Precision measurement of the local velocities of longitudinal and shear waves propagating in shungite and isotropic pyrographite samples was performed by laser ultrasonic techniques. Young's modulus, the shear modulus and Poisson's ratio are calculated, and the chemical composition of the samples is given.

Numerical Investigation of Propagation of Ultrasonic Waves in the Waveguides with Mode Conversion

2013 ◽  
Vol 543 ◽  
pp. 219-222
Author(s):  
Elena Jasiūnienė ◽  
Egidijus Žukauskas ◽  
Rymantas Kažys
Keyword(s):  
Numerical Investigation ◽  
Longitudinal Wave ◽  
Mode Conversion ◽  
Incidence Angle ◽  
Ultrasonic Transducer ◽  
Shear Waves ◽  
Ultrasonic Waves ◽  
Ultrasonic Transducers ◽  
Special Cases ◽  
Longitudinal And Shear Waves

Ultrasonic investigation techniques are widely used in materials characterisation and non-destructive testing applications. In special cases of applications, such as investigation of properties of melted polymers, metals and hot liquids, measurements must be performed in a wide temperature range. However conventional piezoelectric transducers cannot withstand higher temperatures than the Curie temperature. Therefore in order to protect conventional ultrasonic transducers from influence of a high temperature and to avoid depolarization, measurements must be performed using special waveguides with a low thermal conductivity between the object under investigation and the ultrasonic transducer. For measurements of the material properties, such as viscoelastic properties of materials, additional shear wave transducers must be used. In this work approach how to excite both, longitudinal and shear waves using special waveguides with mode conversion, using pair of conventional ultrasonic longitudinal wave transducers is presented. In this work numerical investigation of propagation of longitudinal and shear ultrasonic waves in the waveguides with mode conversion using finite element method and CIVA software was carried out. Modelling of propagation of simultaneously generated longitudinal and shear waves using pair of longitudinal ultrasonic transducers was performed. Influence of temperature gradient to the required incidence angle of the longitudinal wave was evaluated.

Sign in / Sign up

Export Citation Format

Share Document