scholarly journals Numerical Modeling of the Propagation of Infrasonic Acoustic Waves Through the Turbulent Field Generated by the Breaking of Mountain Gravity Waves

2019 ◽  
Vol 46 (10) ◽  
pp. 5526-5534 ◽  
Author(s):  
R. Sabatini ◽  
J. B. Snively ◽  
C. Bailly ◽  
M. P. Hickey ◽  
J. L. Garrison
Keyword(s):  
Numerical Modeling ◽  
Gravity Waves ◽  
Acoustic Waves ◽  
Turbulent Field

scholarly journals TOMOGRAPHY OF THE SOLAR INTERIOR

2006 ◽  
Vol 21 (22) ◽  
pp. 1701-1715 ◽  
Author(s):  
L. GIZON
Keyword(s):  
Gravity Waves ◽  
Acoustic Waves ◽  
Solar Surface ◽  
Three Dimensional ◽  
Magnetic Activity ◽  
Solar Interior ◽  
Turbulent Convection ◽  
Convective Structures ◽  
Surface Gravity Waves ◽  
Rich Spectrum

Solar oscillations consist of a rich spectrum of internal acoustic waves and surface gravity waves, stochastically excited by turbulent convection. They have been monitored almost continuously over the last ten years with high-precision Doppler images of the solar surface. The purpose of helioseismology is to retrieve information about the structure and the dynamics of the solar interior from the frequencies, phases and amplitudes of solar waves. Methods of analysis are being developed to make three-dimensional images of subsurface motions and temperature inhomogeneities in order to study convective structures and regions of magnetic activity, like sunspots.

Interaction of second sound acoustic waves with a counterflow-induced turbulent field

1991 ◽  
Vol 168 (2) ◽  
pp. 93-103 ◽  
Author(s):  
W. Fiszdon ◽  
S.K. Nemirovskii ◽  
M.v. Schwerdtner
Keyword(s):  
Acoustic Waves ◽  
Second Sound ◽  
Turbulent Field

scholarly journals Time-Dependent Propagation of Tsunami-Generated Acoustic–Gravity Waves in the Atmosphere

2020 ◽  
Vol 77 (4) ◽  
pp. 1233-1244 ◽  
Author(s):  
Yue Wu ◽  
Stefan G. Llewellyn Smith ◽  
James W. Rottman ◽  
Dave Broutman ◽  
Jean-Bernard H. Minster
Keyword(s):  
Internal Waves ◽  
Gravity Waves ◽  
Acoustic Waves ◽  
Early Stage ◽  
Vertical Displacement ◽  
Inverse Laplace Transform ◽  
Acoustic Gravity Waves ◽  
Numerical Inverse Laplace Transform ◽  
Wave Development

Abstract Tsunami-generated linear acoustic–gravity waves in the atmosphere with altitude-dependent vertical stratification and horizontal background winds are studied with the long-term goal of real-time tsunami warning. The initial-value problem is examined using Fourier–Laplace transforms to investigate the time dependence and to compare the cases of anelastic and compressible atmospheres. The approach includes formulating the linear propagation of acoustic–gravity waves in the vertical, solving the vertical displacement of waves and pressure perturbations numerically as a set of coupled ODEs in the Fourier–Laplace domain, and employing den Iseger’s algorithm to carry out a fast and accurate numerical inverse Laplace transform. Results are presented for three cases with different atmospheric and tsunami profiles. Horizontal background winds enhance wave advection in the horizontal but hinder the vertical transmission of internal waves through the whole atmosphere. The effect of compressibility is significant. The rescaled vertical displacement of internal waves at 100-km altitude shows an arrival at the early stage of wave development due to the acoustic branch that is not present in the anelastic case. The long-term displacement also shows an O(1) difference between the compressible and anelastic results for the cases with uniform and realistic stratification. Compressibility hence affects both the speed and amplitude of energy transmitted to the upper atmosphere because of fast acoustic waves.

scholarly journals Rotating Detonation: History, Results, Problems

2020 ◽  
Vol 2020 (4) ◽  
pp. 48-60
Author(s):  
Anatoly A. Vasil’ev
Keyword(s):  
Numerical Modeling ◽  
Acoustic Waves ◽  
Rotation Velocity ◽  
Experimental Investigations ◽  
Detonation Waves ◽  
Reaction Products ◽  
Low Velocity ◽  
Acoustic Characteristics ◽  
Transverse Waves ◽  
Rotating Detonation

AbstractAmong of modern papers devoted to numerical modeling of rotated waves the greater part of papers are based on assumption that such wave propagates with velocity equals to the Chapman-Jouguet velocity of ideal detonation model with plane front. But the experimental velocities of rotated detonation waves, as a rule, are less (and even much less) the velocity of ideal Chapman-Jouguet detonation. Such regimes are named as low-velocity detonation or quasi-detonation and its characteristics are practically not investigated carefully. Moreover, similar to the spinning detonation, the strong connection of velocity of rotated transverse waves with the acoustic waves of reaction products was observed. So the new model with an allowance for the losses of impulse and energy must be used at numerical modeling of RDE and new experimental investigations of regimes with understated velocity must be carried out. In given paper some important aspects of rotated detonation waves and new experimental results are analyzed: the multifront system of rotated waves; correlation of rotation velocity of waves with acoustic characteristics of reaction products; streak-records trajectory of rotated waves on moving film; pressure and temperature profiles of rotating waves; velocity deficit and energy-release.

Sculpting and Aerosolizing Pinned Liquid Films With Localized Acoustic Pressures of Surface Acoustic Waves

2012 ◽  
Author(s):  
Daniel Taller ◽  
Hsueh-Chia Chang ◽  
David B. Go
Keyword(s):  
Contact Angle ◽  
Numerical Modeling ◽  
Contact Line ◽  
Acoustic Waves ◽  
Acoustic Pressure ◽  
Surface Acoustic Waves ◽  
Liquid Films ◽  
Solid Substrate ◽  
Planar Surface ◽  
Bulk Film

Due to viscous decay, a planar surface acoustic wave (SAW) diffracting from a solid substrate into a liquid film produces a time-averaged, exponentially decaying acoustic pressure in the film. We show that if the film is pinned against a bounding wall, the localized acoustic pressure generates a sequence of surface drops at the contact line, whose dimensions decay in the same exponential manner as the localized acoustic pressure. The undulating interfacial profile near the contact line also inherits this exponential decay, such that the averaged contact angle is exponentially small. The bulk film topology and the aerosolization mechanism are hence insensitive to the wettability of the surface but are controlled only by the localized acoustic pressure and the decaying undulations it produces at the contact line. The size distribution of surface drops is collapsed under the exponential scaling that depends only on the SAW decay rate and amplitude. Numerical modeling based on the Young-Laplace equation is used to model the liquid profile and to predict two aerosolization regimes.

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