Acoustic diffraction by a half-plane in a viscous fluid medium

2002 ◽  
Vol 112 (4) ◽  
pp. 1288-1296 ◽  
Author(s):  
Anthony M. J. Davis ◽  
Raymond J. Nagem
Keyword(s):  
Viscous Fluid ◽  
Half Plane ◽  
Fluid Medium ◽  
Acoustic Diffraction

Acoustic Diffraction by a Half-Plane in a Viscous Fluid Medium

2001 ◽  
Author(s):  
Anthony M. J. Davis ◽  
Raymond J. Nagem
Keyword(s):  
Fluid Flow ◽  
Velocity Field ◽  
Viscous Fluid ◽  
Plane Wave ◽  
Numerical Computation ◽  
Half Plane ◽  
Fluid Medium ◽  
Viscous Fluid Flow ◽  
Time Harmonic ◽  
Acoustic Diffraction

Abstract We consider the diffraction of a time-harmonic acoustic plane wave by a rigid half-plane in a viscous fluid medium. The linearized equations of viscous fluid flow and the no-slip condition on the half-plane are used to derive a pair of disjoint Wiener-Hopf equations for the fluid stresses and velocities. The Wiener-Hopf equations are solved in conjunction with a requirement that the stresses are integrable near the edge of the half-plane. Specific wave components of the scattered velocity field are given explicitly, and the complete scattered velocity field is given in a form that is suitable for numerical computation.

Boundary Layer Analysis of Acoustic Diffraction by a Half-Plane in a Viscous Fluid Medium

2001 ◽  
Author(s):  
Raymond J. Nagem ◽  
Guido Sandri
Keyword(s):  
Boundary Layer ◽  
Half Plane ◽  
Multiple Scale ◽  
Fluid Viscosity ◽  
Fluid Medium ◽  
Boundary Layer Approximation ◽  
Incompressible Viscous Flow ◽  
Time Harmonic ◽  
Layer Analysis ◽  
Acoustic Diffraction

Abstract We investigate the effects of fluid viscosity on the diffraction of a time-harmonic acoustic plane wave by a semi-infinite half-plane. A boundary layer approximation based on a multiple scale expansion and the known inviscid diffraction solution is used to derive the velocity field near the surface of the half-plane. The boundary layer approximation is compared to an independent incompressible viscous flow solution that is derived for a small circular region in the neighborhood of the edge of the half-plane.

Free vibration analysis of nano-plate in viscous fluid medium using nonlocal elasticity

2019 ◽  
Vol 74 ◽  
pp. 440-448 ◽  
Author(s):  
Shahrokh Hosseini-Hashemi ◽  
Reza Ahmadi Arpanahi ◽  
Sasan Rahmanian ◽  
Ali Ahmadi-Savadkoohi
Keyword(s):  
Viscous Fluid ◽  
Free Vibration ◽  
Nonlocal Elasticity ◽  
Vibration Analysis ◽  
Free Vibration Analysis ◽  
Fluid Medium

Acoustic diffraction by a half plane in a viscous medium

1999 ◽  
Vol 106 (4) ◽  
pp. 2289-2289
Author(s):  
Allan D. Pierce ◽  
Raymond J. Nagem ◽  
Mario Zampolli
Keyword(s):  
Half Plane ◽  
Viscous Medium ◽  
Acoustic Diffraction

Axisymmetric Vibrations of a Piezoelectric Spherical Shell Submerged in a Compressible Viscous Fluid Medium

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Juxi Hu ◽  
Zhiping Qiu ◽  
Tsung-Chow Su
Keyword(s):  
Viscous Fluid ◽  
Natural Frequencies ◽  
Essential Feature ◽  
Elastic Shell ◽  
Dynamic Responses ◽  
Mode Shapes ◽  
Compressible Viscous Fluid ◽  
Previous Theory ◽  
Fluid Medium ◽  
Shell Motion

Axisymmetric vibrations of a hollow piezoelectric sphere submerged in a compressible viscous fluid medium are investigated. The piezoelectric sphere is radially polarized. The differential equations governing the shell motion are obtained by the use of Hamilton’s principle. Based on the classical bending theory of shells, it is shown that all the piezoelectric contributions can be included in the in vacuo natural frequencies and their corresponding mode shapes. As such, the previous theory on elastic shell vibration becomes readily extendable. The flow field, determined by the boundary layer theory, is coupled to the shell motion through no-slip and no-penetrating conditions. It is found that the contribution of the piezoelectric parameters in the thin shell’s free vibration is of small order and is negligible. Natural frequencies and their associated vibration characteristics are numerically obtained and presented for a Polyvinglindene fluoride (PVDF) shell submerged in water. Dynamic responses of a submerged piezoelectric sherical shell, and the associated radiation of sound are investigated. The oscillations are harmonically driven by an axisymmetrically applied electric potential difference across the surface of the shell. The vibrational, fluid loading, and energy flow characteristics are derived and evaluated for a PVDF shell submerged in water. The essential feature of the modal response is determined by various critical frequencies, such as resonant frequencies and vibration-absorbing frequencies. Viscous effect is found noticeable in several cases.

30.—Acoustic Diffraction by an Absorbing Semi-infinite Half Plane in a Moving Fluid

1975 ◽  
Vol 72 (4) ◽  
pp. 337-357 ◽  
Author(s):  
A. D. Rawlins
Keyword(s):  
Fluid Flow ◽  
Half Space ◽  
Half Plane ◽  
Line Source ◽  
Subsonic Flow ◽  
Sound Intensity ◽  
Acoustic Diffraction ◽  
Radiated Sound ◽  
Acoustic Instabilities ◽  
Moving Fluid

SynopsisThe diffraction of a line source of sound by an absorbing semi-infinite half plane in the presence of a fluid flow is examined. It is found that the radiated sound intensity, in the half space in which the source is located, can be considerably reduced by a suitable choice of the absorption parameter. For subsonic flow the system exhibits no acoustic instabilities.

scholarly journals The Effects of Fluid Viscosity on the Orifice Rotameter

2016 ◽  
Vol 16 (2) ◽  
pp. 87-95 ◽  
Author(s):  
Wei Jiang ◽  
Tao Zhang ◽  
Ying Xu ◽  
Huaxiang Wang ◽  
Xiaoli Guo ◽  
...  
Keyword(s):  
Viscous Fluid ◽  
Flow Rate ◽  
Theoretical Models ◽  
Maximum Error ◽  
Measurement Model ◽  
High Viscosity ◽  
Fluid Viscosity ◽  
Fluid Medium ◽  
Viscous Shear Stress ◽  
Viscous Shear

Abstract Due to the viscous shear stress, there is an obvious error between the real flow rate and the rotameter indication for measuring viscous fluid medium. At 50 cSt the maximum error of DN40 orifice rotameter is up to 35 %. The fluid viscosity effects on the orifice rotameter are investigated using experimental and theoretical models. Wall jet and concentric annulus laminar theories were adapted to study the influence of viscosity. And a new formula is obtained for calculating the flow rate of viscous fluid. The experimental data were analyzed and compared with the calculated results. At high viscosity the maximum theoretical results error is 6.3 %, indicating that the proposed measurement model has very good applicability.

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