scholarly journals Sound radiation from a point source moving vertically to a plane interface between two fluids.

1980 ◽  
Vol 1 (4) ◽  
pp. 243-248
Author(s):  
Samon Oie ◽  
Ryoichi Takeuchi
Keyword(s):  
Point Source ◽  
Sound Radiation ◽  
Plane Interface ◽  
Two Fluids

Axisymmetric outflows from binary point-source systems in the presence of an interface

2016 ◽  
Vol 790 ◽  
pp. 205-236
Author(s):  
Lawrence K. Forbes
Keyword(s):  
Binary System ◽  
Point Source ◽  
Numerical Solutions ◽  
Flow Problem ◽  
Surrounding Medium ◽  
Small Deformation ◽  
Point Sources ◽  
Fluid Mixing ◽  
Two Fluids ◽  
Narrow Region

Fluid outflow is considered, from a binary system of two point sources. The sources inject fluid of a lower density than the surrounding medium, and there is a sharp interface separating the two fluids. The overall geometry is taken to be axisymmetric around the line joining the two sources. Numerical solutions are presented for the shape of the interface in unsteady flow, and compared with a linearized solution based on small deformation of the interface from its initial spherical configuration. In addition, a novel spectral method is developed for the solution of the Boussinesq viscous flow problem, accounting exactly for the presence of the two sources and modelling the interface as a narrow region in which fluid mixing is possible. Bipolar outflow jets are seen to be possible.

Reflection maxima for reflections from single interfaces

Geophysics ◽  
1988 ◽  
Vol 53 (2) ◽  
pp. 271-275 ◽  
Author(s):  
C. A. Rendleman ◽  
F. K. Levin
Keyword(s):  
Plane Wave ◽  
Point Source ◽  
Critical Angle ◽  
Maximum Amplitude ◽  
P Wave ◽  
Plane Interface ◽  
Wide Angle ◽  
Mathematical Expressions ◽  
Shed Light

At a workshop on refraction and wide‐angle reflections, Hilterman (1985) pointed out that, in contrast to the plane‐wave case, when there is a point source, a P-wave reflected from a plane interface attains its maximum amplitude at an offset greater than that corresponding to the critical angle (Figure 1). The same conclusion had been drawn earlier by Červený (1967). However, neither Červený’s results, which were based on very complicated mathematical expressions derived by Brekhovskikh (1960), nor Hilterman’s computer‐generated data shed light on the physics implied by the shifted maximum.

Series Expansion Solution for Sound Radiation from Rotating Quadrupole Point Source

AIAA Journal ◽  
2014 ◽  
Vol 52 (5) ◽  
pp. 1086-1095 ◽  
Author(s):  
Yijun Mao ◽  
Chen Xu ◽  
Datong Qi ◽  
Hongtao Tang
Keyword(s):  
Point Source ◽  
Series Expansion ◽  
Sound Radiation

Sound radiation and caustic formation from a point source in a wall shear layer

AIAA Journal ◽  
1994 ◽  
Vol 32 (6) ◽  
pp. 1135-1144 ◽  
Author(s):  
I. David Abrahams ◽  
Gregory A. Kriegsmann ◽  
Edward L. Reiss
Keyword(s):  
Point Source ◽  
Shear Layer ◽  
Sound Radiation ◽  
Wall Shear

scholarly journals Motion of a sphere in the presence of a plane interface. Part 2. An exact solution in bipolar co-ordinates

1980 ◽  
Vol 98 (1) ◽  
pp. 193-224 ◽  
Author(s):  
S. H. Lee ◽  
L. G. Leal
Keyword(s):  
Exact Solution ◽  
General Solution ◽  
Approximate Solutions ◽  
Plane Interface ◽  
Spherical Particles ◽  
Fluid Interface ◽  
Two Fluids ◽  
Freely Suspended ◽  
Velocity Pressure ◽  
Particle Shapes

A general solution for Stokes’ equation in bipolar co-ordinates is derived, and then applied to the arbitrary motion of a sphere in the presence of a plane fluid/fluid interface. The drag force and hydrodynamic torque on the sphere are then calculated for four specific motions of the sphere; namely, translation perpendicular and parallel to the interface and rotation about an axis which is perpendicular and parallel, respectively, to the interface. The most significant result of the present work is the comparison between these numerically exact solutions and the approximate solutions from part 1. The latter can be generalized to a variety of particle shapes, and it is thus important to assess their accuracy for this case of spherical particles where an exact solution can be obtained. In addition to comparisons with the approximate solutions, we also examine the predicted changes in the velocity, pressure and vorticity fields due to the presence of the plane interface. One particularly interesting feature of the solutions is the fact that the direction of rotation of a freely suspended sphere moving parallel to the interface can either be the same as for a sphere rolling along the interface (as might be intuitively expected), or opposite depending upon the location of the sphere centre and the ratio of viscosities for the two fluids.

The reflexion of an acoustic pulse by a plane vortex sheet

1973 ◽  
Vol 74 (2) ◽  
pp. 349-364 ◽  
Author(s):  
D. S. Jones
Keyword(s):  
Point Source ◽  
Relative Motion ◽  
Acoustic Pulse ◽  
Vortex Sheet ◽  
Instability Wave ◽  
Finite Region ◽  
Helmholtz Instability ◽  
Two Fluids ◽  
Reflected Wave

AbstractThis paper deals with the influence of a vortex sheet separating two fluids in relative motion on the radiation from a point source of sound. Both the harmonic and impulsive sources are considered and it is found that waves due to Helmholtz instability must be included in order to ensure that there is no field before the source is excited. The instability wave is confined to a finite region and dominates other disturbances in that region. It is suggested that the instabifity wave is initiated by the unrestricted growth of the specularly reflected wave.

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