Three‐dimensional modal theory of sound propagation in a fluctuating ocean with spatial‐temporal inhomogeneities.

2010 ◽  
Vol 128 (4) ◽  
pp. 2395-2395
Author(s):  
Alexander G. Voronovich ◽  
Vladimir E. Ostashev ◽  
John A. Colosi
Keyword(s):  
Sound Propagation ◽  
Three Dimensional ◽  
Modal Theory

Three dimensional axisymmetric sound propagation through a duct with aerosol

2018 ◽  
Vol 434 ◽  
pp. 261-272
Author(s):  
Ersen Arslan ◽  
Mehmet Çalışkan ◽  
Yusuf Özyörük
Keyword(s):  
Sound Propagation ◽  
Three Dimensional

Three-dimensional parabolic equation model for low frequency sound propagation in irregular urban canyons

2015 ◽  
Vol 137 (1) ◽  
pp. 310-320 ◽  
Author(s):  
Jean-Baptiste Doc ◽  
Bertrand Lihoreau ◽  
Simon Félix ◽  
Cédric Faure ◽  
Guillaume Dubois
Keyword(s):  
Parabolic Equation ◽  
Sound Propagation ◽  
Three Dimensional ◽  
Low Frequency ◽  
Equation Model ◽  
Frequency Sound

scholarly journals Focused sound from three-dimensional sound propagation effects over a submarine canyon

2011 ◽  
Vol 129 (6) ◽  
pp. EL260-EL266 ◽  
Author(s):  
Linus Y. S. Chiu ◽  
Ying-Tsong Lin ◽  
Chi-Fang Chen ◽  
Timothy F. Duda ◽  
Brian Calder
Keyword(s):  
Sound Propagation ◽  
Three Dimensional ◽  
Submarine Canyon ◽  
Propagation Effects

Disturbance energy growth in core–annular flow

2014 ◽  
Vol 747 ◽  
pp. 44-72 ◽  
Author(s):  
A. Orazzo ◽  
G. Coppola ◽  
L. de Luca
Keyword(s):  
Pipe Flow ◽  
Annular Flow ◽  
Three Dimensional ◽  
Point Of View ◽  
Transition To Turbulence ◽  
Navier Stokes ◽  
Water Mixture ◽  
Horizontal Pipe ◽  
Transient Phenomena ◽  
Modal Theory

AbstractThe linear stability of the horizontal pipe flow of an equal density oil–water mixture, arranged as acore–annular flow(CAF), is here reconsidered from the point of view of non-modal analysis in order to assess the effects of non-normality of the linearized Navier–Stokes operator on the transient evolution of small disturbances. The aim of this investigation is to give insight into physical situations in which poor agreement occurs between the predictions of linear modal theory and classical experiments. The results exhibit high transient amplifications of the energy of three-dimensional perturbations and, in analogy with single-fluid pipe flow, the largest amplifications arise for non-axisymmetric disturbances of vanishing axial wavenumber. Energy analysis shows that the mechanisms leading to these transient phenomena mostly occur in the annulus, occupied by the less viscous fluid. Consequently, higher values of energy amplifications are obtained by increasing the gap between the core and the pipe wall and the annular Reynolds number. It is argued that these linear transient mechanisms of disturbance amplification play a key role in explaining the transition to turbulence of CAF.

scholarly journals Resonant three-dimensional nonlinear sloshing in a square-base basin. Part 4. Oblique forcing and linear viscous damping

2017 ◽  
Vol 822 ◽  
pp. 139-169 ◽  
Author(s):  
Odd M. Faltinsen ◽  
Alexander N. Timokha
Keyword(s):  
Steady State ◽  
Three Dimensional ◽  
Finite Depth ◽  
Width Ratio ◽  
Viscous Damping ◽  
Response Curves ◽  
Viscous Boundary Layer ◽  
Wave Regime ◽  
Modal Theory ◽  
Nonlinear Sloshing

Faltinsen et al. (J. Fluid Mech., vol. 487, 2003, pp. 1–42) (henceforth, Part 1) examined an undamped nonlinear resonant steady-state sloshing in a square-base tank by developing an approximate (asymptotic) Narimanov–Moiseev-type multimodal theory. The focus was on longitudinal and diagonal harmonic tank excitations. Neglecting the linear viscous boundary-layer damping was justified for model tanks with breadths of the order of metres. However, nonlinear sloshing in clean tanks of smaller size (count in centimetres) may be affected by damping in finite depth conditions. Qualitative and quantitative properties of the damped resonant steady-state sloshing in a square-base tank are now studied by using the modal theory from Part 1 equipped with the linear damping terms. The tank harmonically oscillates along an arbitrary horizontal (oblique) direction. An analytical asymptotic steady-state undamped solution is derived and the corresponding response curves are analysed versus the forcing direction. When the tank width $=$ breadth $=$ $L\sim 10$  cm, the surface tension effect on the free-surface dynamics can be neglected but the linear viscous damping should be included into the Narimanov–Moiseev nonlinear asymptotic modal theory. We analytically show that the steady-state damped sloshing possesses a series of distinguishing features so that, e.g. the square-like standing wave regime fully disappears and becomes replaced by swirling. Typical response curves of the damped steady-state resonant sloshing are studied for the liquid depth-to-width ratio exceeding 0.5. The computational results of the steady-state resonant response amplitudes are in a satisfactory agreement with observations and measurements by Ikeda et al. (J. Fluid Mech., vol. 700, 2012, pp. 304–328), which were conducted with a relatively small laboratory container.

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