TWO-DIMENSIONAL FINITE AMPLITUDE ACOUSTIC WAVES RADIATING FROM A FLAT PLATE IN ARBITRARY PERIODIC VIBRATION.

1979 ◽  
Vol 40 (C8) ◽  
pp. C8-35-C8-38
Author(s):  
J. H. Ginsberg
Keyword(s):  
Flat Plate ◽  
Acoustic Waves ◽  
Finite Amplitude ◽  
Two Dimensional ◽  
Periodic Vibration

scholarly journals Boundary-layer receptivity for a parabolic leading edge. Part 2. The small-Strouhal-number limit

1997 ◽  
Vol 353 ◽  
pp. 205-220 ◽  
Author(s):  
P. W. HAMMERTON ◽  
E. J. KERSCHEN
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Acoustic Waves ◽  
Asymptotic Theory ◽  
Free Stream ◽  
Leading Edge ◽  
Numerical Results ◽  
Two Dimensional ◽  
Mean Flow ◽  
The Mean

In Hammerton & Kerschen (1996), the effect of the nose radius of a body on boundary-layer receptivity was analysed for the case of a symmetric mean flow past a two-dimensional body with a parabolic leading edge. A low-Mach-number two-dimensional flow was considered. The radius of curvature of the leading edge, rn, enters the theory through a Strouhal number, S=ωrn/U, where ω is the frequency of the unsteady free-stream disturbance and U is the mean flow speed. Numerical results revealed that the variation of receptivity for small S was very different for free-stream acoustic waves propagating parallel to the mean flow and those free-stream waves propagating at an angle to the mean flow. In this paper the small-S asymptotic theory is presented. For free-stream acoustic waves propagating parallel to the symmetric mean flow, the receptivity is found to vary linearly with S, giving a small increase in the amplitude of the receptivity coefficient for small S compared to the flat-plate value. In contrast, for oblique free-stream acoustic waves, the receptivity varies with S1/2, leading to a sharp decrease in the amplitude of the receptivity coefficient relative to the flat-plate value. Comparison of the asymptotic theory with numerical results obtained in the earlier paper confirms the asymptotic results but reveals that the numerical results diverge from the asymptotic result for unexpectedly small values of S.

scholarly journals Two-Dimensional Nonlinear Propagation of Ion Acoustic Waves through KPB and KP Equations in Weakly Relativistic Plasmas

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
M. G. Hafez ◽  
M. R. Talukder ◽  
M. Hossain Ali
Keyword(s):  
Acoustic Waves ◽  
Finite Amplitude ◽  
Reductive Perturbation Method ◽  
Nonlinear Propagation ◽  
Two Dimensional ◽  
Ion Acoustic Waves ◽  
Ion Acoustic ◽  
Component Plasma ◽  
Basic Characteristics ◽  
Superthermal Electrons And Positrons

Two-dimensional three-component plasma system consisting of nonextensive electrons, positrons, and relativistic thermal ions is considered. The well-known Kadomtsev-Petviashvili-Burgers and Kadomtsev-Petviashvili equations are derived to study the basic characteristics of small but finite amplitude ion acoustic waves of the plasmas by using the reductive perturbation method. The influences of positron concentration, electron-positron and ion-electron temperature ratios, strength of electron and positrons nonextensivity, and relativistic streaming factor on the propagation of ion acoustic waves in the plasmas are investigated. It is revealed that the electrostatic compressive and rarefactive ion acoustic waves are obtained for superthermal electrons and positrons, but only compressive ion acoustic waves are found and the potential profiles become steeper in case of subthermal positrons and electrons.

On the propagation of acoustic waves in quasi-two-dimensional conductors in a quantizing magnetic field

2003 ◽  
Vol 29 (7) ◽  
pp. 609-612 ◽  
Author(s):  
O. V. Kirichenko ◽  
V. G. Peschansky ◽  
O. Galbova ◽  
G. Ivanovski ◽  
D. Krstovska
Keyword(s):  
Magnetic Field ◽  
Acoustic Waves ◽  
Two Dimensional ◽  
Quantizing Magnetic Field

Tunable Band Gaps of Acoustic Waves in Two-Dimensional Phononic Crystals With Reticular Band Structures

2009 ◽  
Author(s):  
Zi-Gui Huang ◽  
Yunn-Lin Hwang ◽  
Pei-Yu Wang ◽  
Yen-Chieh Mao
Keyword(s):  
Acoustic Waves ◽  
Composite Structures ◽  
Phononic Crystals ◽  
Band Gaps ◽  
Sound Insulation ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Elastic Band ◽  
Band Structures ◽  
Elastic Band Gaps

The excellent applications and researches of so-called photonic crystals raise the exciting researches of phononic crystals. By the analogy between photon and phonon, repetitive composite structures that are made up of different elastic materials can also prevent elastic waves of some certain frequencies from passing by, i.e., the frequency band gap features also exist in acoustic waves. In this paper, we present the results of the tunable band gaps of acoustic waves in two-dimensional phononic crystals with reticular band structures using the finite element method. Band gaps variations of the bulk modes due to different thickness and angles of reticular band structures are calculated and discussed. The results show that the total elastic band gaps for mixed polarization modes can be enlarged or reduced by adjusting the orientation of the reticular band structures. The phenomena of band gaps of elastic or acoustic waves can potentially be utilized for vibration-free, high-precision mechanical systems, and sound insulation.

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