scholarly journals Linking the viscous grain-shearing mechanism of wave propagation in marine sediments to fractional calculus

2016 ◽  
Vol 139 (4) ◽  
pp. 2010-2010
Author(s):  
Vikash Pandey ◽  
Sverre Holm
Keyword(s):  
Wave Propagation ◽  
Fractional Calculus ◽  
Marine Sediments ◽  
Mechanism Of Wave Propagation ◽  
Shearing Mechanism

In situ measurements of compressional and shear wave propagation in marine sediments and comparison to geoacoustic models

2018 ◽  
Vol 144 (3) ◽  
pp. 1960-1960
Author(s):  
Kevin M. Lee ◽  
Megan S. Ballard ◽  
Andrew R. McNeese ◽  
Gabriel R. Venegas ◽  
Preston S. Wilson
Keyword(s):  
Wave Propagation ◽  
Shear Wave ◽  
Marine Sediments ◽  
In Situ Measurements

scholarly journals Assessing the Power of Intensity Interaction between the Solid and Fluid Phases in the Unconsolidated Water-Saturated Sandy Marine Sediments at Shear Wave Propagation

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
V. A. Lisyutin ◽  
O. R. Lastovenko ◽  
◽  
Keyword(s):  
Wave Propagation ◽  
Shear Wave ◽  
Attenuation Coefficient ◽  
Marine Sediments ◽  
Pore Space ◽  
Equation Of Motion ◽  
Relative Movement ◽  
Two Phase ◽  
Dissipative Effects ◽  
Sandy Sediments

Purpose. Propagation of a shear wave in sandy marine sediments is considered. The acoustic properties of a shear wave are the phase velocity and the attenuation coefficient. It is known that in dry sandy sediments, the attenuation coefficient is directly proportional to frequency. In the saturated mediums, there are the deviations from this law that implies existence of two physical mechanisms of losses – the intergranular friction and viscous loss. The study is aimed at developing a two-phase theoretical model of the shear wave propagation in the unconsolidated marine sediments, and at identifying the dissipative effects caused by the fluid relative movement in the pore space. Methods and Results. The intergranular friction is modeled using a springpot, which represents an element combing conservative properties of a spring and dissipative ones of a dashpot. The equation of motion is applied, where a part of fluid is assumed to be associated with the media solid phase and another part is considered to be mobile. For a harmonic displacement, the equations of state and the equation of motion yield a new two-phase dispersion relation (the theory of Grain Shearing + + Effective Density, or GS + EDs, for short). The results of the GS + EDs theory are compared with the data of the velocity and attenuation measurements taken from the open sources. It is shown that during propagation of the compressional and shear waves, the mechanisms of interaction between the granules, and between the granules and fluid are not similar. Character of the changes in the grain-tograin friction parameters when the pore space is saturated with fluid, is analyzed. Conclusion. Manifestation of the dissipative effects resulting from the pore saturation with fluid depends on the density of the granules packing. In case of a dense packing, there are no conditions for the fluid relative movement, and the sandy sediments exhibit the property of a constant Q-factor. If the packing is loose, the viscous losses make a significant contribution, and the attenuation frequency dependence is nonlinear. The effective pore sizes for the compression and shear waves do not coincide.

scholarly journals Impacts of simulated infaunal activities on acoustic wave propagation in marine sediments

2020 ◽  
Vol 147 (2) ◽  
pp. 812-823
Author(s):  
Kelly M. Dorgan ◽  
Will Ballentine ◽  
Grant Lockridge ◽  
Erin Kiskaddon ◽  
Megan S. Ballard ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Acoustic Wave ◽  
Marine Sediments ◽  
Acoustic Wave Propagation

scholarly journals Wave Propagation Across Solid-Fluid Interface With Fluid-Structure Interaction

2015 ◽  
Author(s):  
Tomohisa Kojima ◽  
Kazuaki Inaba ◽  
Kosuke Takahashi
Keyword(s):  
Wave Propagation ◽  
Theoretical Model ◽  
Characteristic Impedance ◽  
Fluid Structure Interaction ◽  
Fluid Interface ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Mechanism Of Wave Propagation ◽  
Free Falling ◽  
The Impact

This paper reports on investigations conducted with a view towards developing a theoretical model for wave propagation across solid-fluid interfaces with fluid-structure interaction. Although many studies have been conducted, the mechanism of wave propagation close to the solid-fluid interface remains unclear. Consequently, our aim is to clarify the mechanism of wave propagation across the solid-fluid interface with fluid-structure interaction and develop a theoretical model to explain this phenomenon. In experiments conducted to develop the theory, a free-falling steel projectile is used to impact the top of a solid buffer placed immediately above the surface of water within a polycarbonate tube. The stress waves created as a result of the impact of the projectile propagated through the buffer and reached the interface of the buffer and water (fluid) in the tube. Two different buffers (polycarbonate and aluminum) were used to examine the interaction effects. The results of the experiments indicated that the amplitude of the interface pressure increased in accordance with the characteristic impedance of the solid medium. This cannot be explained by the classical theory of wave reflection and transmission. Thus, it is clear that on the solid-fluid interface with fluid-structure interaction, classical theories alone cannot precisely predict the generated pressure.

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