Ultrasonic studies of liquid helium in porous media

1987 ◽  
Vol 65 (11) ◽  
pp. 1557-1559 ◽  
Author(s):  
J. R. Beamish ◽  
K. Warner
Keyword(s):  
Porous Media ◽  
Sound Propagation ◽  
Porous Ceramic ◽  
Ultrasonic Waves ◽  
Effective Density ◽  
Biot Theory ◽  
Fluid Density ◽  
Normal Fluid ◽  
Superfluid Fraction ◽  
Viscous Losses

We have studied the propagation of 12 MHz transverse ultrasonic waves in a porous ceramic containing liquid 4He. Both the sound velocity and the attenuation clearly show the superfluid nature of helium. The helium in the pores increases the system's effective density by an amount proportional to the normal-fluid density and so decreases the sound speed. The decoupling of the superfluid fraction below the lambda transition allows us to use the shear wave essentially as a "high-frequency torsional oscillator" to determine the superfluid density and pore tortuosity. The sound attenuation in this system is due to the same mechanism as for fourth sound, namely, viscous losses due to motion of the normal-fluid component. We observed an attenuation proportional to the normal-fluid density and compare this result to predictions of the Biot theory of sound propagation in fluid-filled porous media.

Research of Porous Solid - Fluid Interface Scholte Wave

2012 ◽  
Vol 538-541 ◽  
pp. 2175-2180
Author(s):  
Zu Feng Xie ◽  
Qing Bang Han ◽  
Chang Ping Zhu
Keyword(s):  
Porous Media ◽  
Function Method ◽  
Sound Propagation ◽  
Secular Equation ◽  
Biot Theory ◽  
Propagation Characteristics ◽  
Fluid Interface ◽  
Medium Interface ◽  
Interface Wave ◽  
Scholte Wave

This paper establishes the theoretical model of Scholte wave velocity on the fluid-porous medium interface based on the Biot theory of porous media. We firstly simulates and analysis sound propagation characteristics of fluid-saturated porous, and then we deduces the secular equation of fluid-solid interface wave on semi-infinite half-space applying potential function method. This study will provide a theoretical guidance of detecting the interface wave between fluid and porous media.

Comparison of sound speed and attenuation measured in a sandy sediment to predictions based on the Biot theory of porous media

2002 ◽  
Vol 27 (3) ◽  
pp. 413-428 ◽  
Author(s):  
K.L. Williams ◽  
D.R. Jackson ◽  
E.I. Thorsos ◽  
Dajun Tang ◽  
S.G. Schock
Keyword(s):  
Porous Media ◽  
Sound Speed ◽  
Biot Theory ◽  
Sandy Sediment ◽  
Theory Of Porous Media

Mathematical Formulation of the Global Coefficients of Transmission and Reflection of Ultrasonic Waves in Bi-Phase Porous Medium

2015 ◽  
Vol 1101 ◽  
pp. 471-479
Author(s):  
Georges Freiha ◽  
Hiba Othman ◽  
Michel Owayjan
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Wave Propagation ◽  
Mathematical Formulation ◽  
Ultrasonic Waves ◽  
Ultrasonic Wave Propagation ◽  
Local Coefficients ◽  
Important Field ◽  
New Formulation ◽  
Transmission And Reflection

The study of signals propagation inside porous media is an important field especially in the biomedical research related to compact bones. The purpose of this paper is to determine a mathematical formulation of the global coefficients of transmission and reflection of nondestructive ultrasonic waves in any bi-phase porous medium. Local coefficients of transmission and reflection on the interface of the porous medium will be determined based on a study of boundary conditions. The behavior of different waves inside the porous medium will be developed so that we can derive a new formulation of global coefficients that takes interior phenomena into consideration. Results are found independently of the geometrical and physical characteristics of the medium. Note that this study is based on normal incident ultrasonic wave propagation.

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