Estimation of internal solitary wave propagation speed in the Andaman Sea using multi–satellite images

Abstract The non-destructive wave propagation technique is used to estimate the wood’s modulus of elasticity. The propagation speed of ultrasonic waves is influenced by some factors, among them: the type of transducer used in the test, the form of coupling and the sensitivity of the transducers. The objective of the study was to evaluate the influence of the contact pressure of the transducers on the ultrasonic speed. Ninety-eight tests were carried out on specimens of the species Eucalyptus grandis, with dimensions of 120 × 120 × 50 mm. The calibration of the pressure exerted by the transducer was controlled by a pressure gauge using a previously calibrated load cell. The robust statistical analysis allowed to validate the experimental results and to obtain consistent conclusions. The results showed that the wave propagation speed is not influenced by the pressure exerted by the transducer.

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Pressure Wave Propagation Speed in Underground Diversion Channel Flow with Enclosed Pressurized Air.

Doboku Gakkai Ronbunshu ◽

10.2208/jscej.1997.579_191 ◽

1997 ◽

pp. 191-196

Author(s):

Noboru Sukegawa ◽

Katsuya Tanizawa ◽

Kazutoshi Arai

Keyword(s):

Wave Propagation ◽

Channel Flow ◽

Pressure Wave ◽

Propagation Speed ◽

Diversion Channel ◽

Wave Propagation Speed

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К теории рассеяния Мандельштама-Бриллюэна в плазменном слое

Журнал технической физики ◽

10.21883/os.2020.01.48844.271-19 ◽

2020 ◽

Vol 128 (1) ◽

pp. 98

Author(s):

С.А. Двинин ◽

Д.К. Солихов ◽

Ш.С. Нурулхаков

Keyword(s):

Wave Propagation ◽

Pump Wave ◽

Plasma Layer ◽

Brillouin Scattering ◽

Propagation Speed ◽

Local Source ◽

Arbitrary Angle ◽

Perturbation Amplitude ◽

Wave Propagation Speed ◽

Over Time

The evolution of a perturbation from a local source for Mandel'shtam-Brillouin scattering in a plasma layer with unlimited length is calculated. Perturbation over time in this case can either leave the scattering region through one of the two boundaries, or propagate along the layer at a speed below sound wave propagation speed, with an exponential growth, or a fall in perturbation amplitude. In the particular case of strictly backward scattering (the scattering angle is π), this propagation velocity is zero. The paper calculates the threshold instability fields and the instability increments, taking into account both convective losses and collisional attenuation of waves. It is shown that the instability threshold for scattering at an arbitrary angle can be lower than for strictly backwards scattering and when the threshold is exceeded by the intensity of the pump wave; the scattering increment at an angle can also be higher than the increment for backscattering. When the threshold is greatly exceeded, the convective losses can be neglected, and the largest increment is observed for backward scattering.

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Analytical and Optimization Study of Propagation and Reduction of Wave in Granular Sand by DEM Method

European Journal of Computational Mechanics ◽

10.13052/ejcm1779-7179.29464 ◽

2021 ◽

Author(s):

Amin Moslemi Petrudi ◽

Masoud Rahmani

Keyword(s):

Wave Propagation ◽

Particle Density ◽

Propagation Speed ◽

Granular Soils ◽

Discrete Elements ◽

Factors Affecting ◽

Interparticle Force ◽

Optimization Study ◽

Solution Methods ◽

Wave Propagation Speed

In this research, the discrete element method has been used to analyze wave propagation and to investigate the factors affecting wave reduction in granular soils. The method of discrete elements is important because of the possibility of preparing completely similar specimens and examining the effect of changes in a certain parameter on the Behavior of the specimens. This method also provides an understanding of the changes that have occurred at the micro-scale of granular materials that are not achievable with other laboratory and numerical methods. To model the specimens, a set of disks with specific granulation has been used for two-dimensional studies. PFC 2D software has been used to perform simulations and related analyzes such as interparticle force. The DEM code in MATLAB is used to check the wave depreciation. In this research, the optimization process was performed using experimental data and the Taguchi method using the DEM method. The results of this study show that there is a direct relationship between the number of particle set contacts and the wave propagation speed. Also, material properties such as particle density are the most important parameters affecting wave velocity. The results of the method (DEM) are done with PFC 2D software and a comparison between the results of this method with the solution methods used by other researchers is shown to be a good match.

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Statistical properties of the internal solitary wave ensemble

10.5194/egusphere-egu21-1830 ◽

2021 ◽

Author(s):

Tatiana Talipova ◽

Ekaterina Didenkulova ◽

Anna Kokorina ◽

Efim Pelinovsky

Keyword(s):

Wave Propagation ◽

Solitary Wave ◽

Solitary Waves ◽

Internal Solitary Wave ◽

Statistical Moments ◽

Nonlinear Propagation ◽

Positive Sign ◽

Cubic Nonlinearity ◽

Gardner Equation ◽

Water Stratification

Internal solitary wave ensembles are often observed on the ocean shelves. The long internal baroclinic tide is generated by a barotropic tide on the shelf edges, and then transforms into the soliton-like wave packets during the nonlinear propagation to the beach. The tide is a periodic process and the solitary wave ensemble appears on the shelf usually each semi-diurnal period of 12.4 hours. This process is very sensitive to the variation of the tide characteristics and the hydrology.We study the propagation of the soliton ensembles numerically in the framework of the spatial form of the Gardner equation (i.e., the Korteweg-de Vries equation with both, quadratic and cubic nonlinearities) assuming horizontally uniform background and applying periodic conditions in time. The water stratification and the local depth are taken similar to the conditions of the north-western Australian shelf, where the stratification admits the existence of solitons but not breathers. The numerical simulation is performed using the Gardner equation with the negative sign of the cubic nonlinearity. For the study of the statistic properties of the solitary waves we use the ensemble of 50 realizations with the same set of 13 solitary waves which are located randomly. The histograms of the wave amplitudes change as the waves travel. The histogram variations become significant after 50 km of the wave propagation. The third (skewness) and the fourth (kurtosis) statistical moments are computed versus the travel distance. It is shown that the both moments decrease by 20% when the solitary wave groups travel for about 150 km.A similar simulation is conducted for a variable background within the framework of the variable-coefficient Gardner equation. At some location the water stratification corresponds to the positive sign of the local coefficient of the cubic nonlinearity, and then internal breathers may exist. The wave propagation in horizontally inhomogeneous hydrology leads to the occurrence of complicated patterns of solitons and breathers; in the course of the transformation they can disintegrate or form internal rogue waves. Under these conditions the statistical moments of the wave field are essentially different from case when the breather-like waves cannot occur.The research was supported by the RFBR grants No 19-05-00161 (TT and EP) and 19-35-60022 (ED). The Foundation for the Advancement of Theoretical Physics and Mathematics &#8220;BASIS&#8221; (&#8470; 20-1-3-3-1) is also acknowledged by ED

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Axial force measurement for U-bolt using wave propagation speed monitoring

The Journal of the Acoustical Society of America ◽

10.1121/1.4969304 ◽

2016 ◽

Vol 140 (4) ◽

pp. 3002-3002

Author(s):

Gyungmin Toh ◽

Dongki Min ◽

Jaehong Lee ◽

Junhong Park

Keyword(s):

Wave Propagation ◽

Axial Force ◽

Force Measurement ◽

Propagation Speed ◽

Wave Propagation Speed

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Extension of Campbell's Major Resonance With Experimental Demonstration

Journal of Vibration and Acoustics ◽

10.1115/1.4024209 ◽

2013 ◽

Vol 135 (5) ◽

Author(s):

Robert P. Czachor

Keyword(s):

Wave Propagation ◽

Rotational Velocity ◽

Propagation Speed ◽

Experimental Demonstration ◽

Adjacent Structure ◽

Component Test ◽

Turbine Disc ◽

Wave Propagation Speed ◽

Trans Asme ◽

Classic Paper

The interaction of vibratory traveling waves in rotating and stationary axisymmetric components is examined. In the most general case, a resonance can occur when the wave propagation speed in a first structure is equal in magnitude and direction to the rotational velocity of an adjacent structure. When a backward wave in a rotor appears stationary, a major resonance, as discussed in Wilfred Campbell's classic paper (Campbell, W., 1924, “The Protection of Steam Turbine Disc Wheels from Axial Vibrations,” Trans ASME, 46, pp. 31–160), results. A related resonance has been observed when the wave propagation speed in the stator is equal to the physical speed of the adjacent rotor. A third mechanism is derived for resonance between a wave in rotor 1 and a co- or counter-rotating rotor 2. Description of a component test which demonstrated this final phenomenon is provided.

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