Utilizing the solution of sound diffraction by a thin screen to evaluate infrasound waves attenuated around volcano topography

2020 ◽  
Vol 402 ◽  
pp. 106983
Author(s):  
Kyoka Ishii ◽  
Akihiko Yokoo ◽  
Masato Iguchi ◽  
Eisuke Fujita
Keyword(s):  
Sound Diffraction ◽  
Thin Screen

Sound diffraction by a partially inclined noise barrier

2001 ◽  
Vol 62 (9) ◽  
pp. 1107-1121 ◽  
Author(s):  
Byung-Joo Jin ◽  
Hyun-Sil Kim ◽  
Hyun-Ju Kang ◽  
Jae-Seung Kim
Keyword(s):  
Noise Barrier ◽  
Sound Diffraction

Analytical representation of hydrophone complex frequency response

2021 ◽  
pp. 16-20
Author(s):  
Alexander E. Isaev
Keyword(s):  
Frequency Response ◽  
Complex Variable ◽  
Active Element ◽  
Analytical Representation ◽  
Complex Frequency ◽  
Minimum Phase ◽  
Experimental Frequency ◽  
Resonance Properties ◽  
Fractional Rational Function ◽  
Sound Diffraction

The problem of analytical representation of hydrophone complex frequency response based on a model consisting of an advance line and a minimum-phase part, which describing the effect of sound diffraction and resonance properties of an active element, is considered. Algorithms are proposed for approximating the hydrophone complex frequency response by a fractional-rational function of the complex variable according to the data of the hydrophone amplitude-frequency and/or phasefrequency responses. Examples of the application of these algorithms for processing experimental frequency characteristics of hydrophones are given.

Uniform theory of diffraction (UTD)-based solution for sound diffraction caused by an array of obstacles

2017 ◽  
Vol 142 (2) ◽  
pp. 902-907
Author(s):  
José-Víctor Rodríguez ◽  
Juan Pascual-García ◽  
María-Teresa Martínez-Inglés ◽  
Jose-Maria Molina-Garcia-Pardo ◽  
Leandro Juan-Llácer
Keyword(s):  
Uniform Theory Of Diffraction ◽  
Sound Diffraction

scholarly journals Sound diffraction on an elastic spheroidal shell

2021 ◽  
Vol 3 (397) ◽  
pp. 97-114
Author(s):  
A. Kleschev ◽  
Keyword(s):  
Group Velocity ◽  
Planar Waveguide ◽  
Sound Propagation ◽  
Spectral Characteristics ◽  
Sound Field ◽  
Signal Propagation ◽  
Elastic Bottom ◽  
Harmonic Signals ◽  
Scattered Fields ◽  
Sound Diffraction

Object and purpose of research. This paper obtains solutions and performs estimations of characteristics of sound reflection and scattering by ideal and elastic bodies of various shapes (analytical and non-analytical) near media interface, or underwater sonic channel, or in a planar waveguide with a solid elastic bottom. Materials and methods. The harmonic signals are investigated with the method of normal waves based on the phase velocity of signal propagation, and impulse signals related to the energy transfer are studied using the method of real and imaginary sources and scatterers based on the group velocity of propagation. Main results. The scattered sound field is calculated for ideal spheroids (elongated and compressed) at fluid – ideal medium interface. The spectrum of a scattered impulse signal is calculated for a body placed in a sonic channel. First reflected impulses are found for an ideal spheroid in a planar waveguide with anisotropic bottom. Conclusion. In the studies of diffraction characteristics of bodies at media interfaces it was found that the main contribution to scattered field is given by interference of scattered fields rather than interaction of scatterers (real or imaginary). It is shown that at long distances the spectral characteristics of the channel itself have a prevalent role. When impulse sound signals in the planar waveguide are used, it is necessary to apply the method of real and imaginary sources and scatterers based on the group velocity of sound propagation.

Thin Screen

2011 ◽  
pp. 97-115
Author(s):  
Shalin Hai-Jew
Keyword(s):  
Virtual Reality ◽  
Virtual Worlds ◽  
Depth Perception ◽  
Meta Analysis ◽  
Human Behaviors ◽  
Design Concepts ◽  
Brain Functions ◽  
Desktop Virtual Reality ◽  
Conducting Research ◽  
Thin Screen

Human depth perception involves complex visual and brain functions. Depth perception in desktop virtual reality has become more important given the uses of such spaces for learning, training, collaboration, simulations, showcasing work, and conducting research on human behaviors. This chapter involves a meta-analysis of the extant research on human depth perception in virtual worlds. It posits some early design concepts for both the creation and evolution of such spaces but also their deployment for educational purposes.

A Method of Exhibiting Sound Diffraction Patterns

1954 ◽  
Vol 22 (7) ◽  
pp. 478-480
Author(s):  
P. L. Howe ◽  
I. R. Neilsen
Keyword(s):  
Diffraction Patterns ◽  
Sound Diffraction

Sound diffraction at a trailing edge

1981 ◽  
Vol 108 ◽  
pp. 443-460 ◽  
Author(s):  
S. W. Rienstra
Keyword(s):  
Vortex Shedding ◽  
Pulse Wave ◽  
Layer Structure ◽  
Harmonic Wave ◽  
Sound Field ◽  
Edge Condition ◽  
Trailing Edge ◽  
Kutta Condition ◽  
High Reynolds ◽  
Sound Diffraction

The diffraction of externally generated sound in a uniformly moving flow at the trailing edge of a semi-infinite flat plate is studied. In particular, the coupling of the sound field to the hydrodynamic field by way of vortex shedding from the edge is considered in detail, both in inviscid and in viscous flow.In the inviscid model the (two-dimensional) diffracted fields of a cylindrical pulse wave, a plane harmonic wave and a plane pulse wave are calculated. The viscous proess of vortex shedding is represented by an appropriate trailing-edge condition. Two specific cases are compared, in one of which the full Kutta condition is applied, and in the other no vortex shedding is permitted. The results show good agreement with Heavens’ (1978) observations from his schlieren photographs, and confirm his conclusions. It is further demonstrated, by an explicit expression, that the sound power absorbed by the wake may be positive or negative, depending on Mach number and source position. So the process of vortex shedding does not necessarily imply an attenuation of the sound.In the viscous model a high-Reynolds-number approximation is constructed, based on a triple-deck boundary-layer structure, matching the harmonic plane wave outer solution to a known incompressible inner solution near the edge, to obtain the viscous correction to the Kutta condition.

Sign in / Sign up

Export Citation Format

Share Document