scholarly journals Internal waves in marginally stable abyssal stratified flows

2018 ◽  
Author(s):  
Nikolay I. Makarenko ◽  
Janna L. Maltseva ◽  
Eugene G. Morozov ◽  
Roman Y. Tarakanov ◽  
Kseniya A. Ivanova
Keyword(s):  
Internal Waves ◽  
Travelling Waves ◽  
Fluid Flows ◽  
Wave Model ◽  
Velocity Shear ◽  
Interfacial Velocity ◽  
Long Wave ◽  
Scaling Procedure ◽  
Upstream Flow ◽  
Exponential Stratification

Abstract. The problem on internal waves in a weakly stratified two-layered fluid is studied semi-analytically. We discuss the 2.5-layer fluid flows with exponential stratification of both layers. The long-wave model describing travelling waves is constructed by means of scaling procedure with a small Boussinesq parameter. It is demonstrated that solitary wave regimes can be affected by the Kelvin–Helmholtz instability arising due to interfacial velocity shear in upstream flow.

scholarly journals Internal waves in marginally stable abyssal stratified flows

2018 ◽  
Vol 25 (3) ◽  
pp. 659-669 ◽  
Author(s):  
Nikolay Makarenko ◽  
Janna Maltseva ◽  
Eugene Morozov ◽  
Roman Tarakanov ◽  
Kseniya Ivanova
Keyword(s):  
Internal Waves ◽  
Travelling Waves ◽  
Fluid Flows ◽  
Wave Model ◽  
Velocity Shear ◽  
Interfacial Velocity ◽  
Long Wave ◽  
Scaling Procedure ◽  
Upstream Flow ◽  
Exponential Stratification

Abstract. The problem on internal waves in a weakly stratified two-layer fluid is studied semi-analytically. We discuss the 2.5-layer fluid flows with exponential stratification of both layers. The long-wave model describing travelling waves is constructed by means of a scaling procedure with a small Boussinesq parameter. It is demonstrated that solitary-wave regimes can be affected by the Kelvin–Helmholtz instability arising due to interfacial velocity shear in upstream flow.

Nonlinear Internal Waves in Stratified Fluid With Homogeneous Layer

2005 ◽  
Author(s):  
Nikolai I. Makarenko ◽  
Janna L. Maltseva
Keyword(s):  
Internal Waves ◽  
Lower Layer ◽  
Nonlinear Ordinary Differential Equation ◽  
Homogeneous Layer ◽  
Constant Density ◽  
Long Wave ◽  
Scaling Procedure ◽  
Internal Bores ◽  
Long Wave Approximation ◽  
Exponential Stratification

The problem of steady internal waves in a weakly stratified two-layered fluid is studied analytically. We discuss the model with a constant density in lower layer and exponential stratification in the other one. The long-wave approximation using a scaling procedure with small Boussinesq parameter is constructed. The nonlinear ordinary differential equation describing large amplitude solitary waves and internal bores is obtained.

Periodic travelling waves for a generalized long wave model

2015 ◽  
Vol 9 ◽  
pp. 6747-6756
Author(s):  
Alex M. Montes ◽  
Ricardo Cordoba
Keyword(s):  
Travelling Waves ◽  
Wave Model ◽  
Long Wave

scholarly journals Two-dimensional pulse dynamics and the formation of bound states on electrified falling films

2018 ◽  
Vol 855 ◽  
pp. 210-235 ◽  
Author(s):  
M. G. Blyth ◽  
D. Tseluiko ◽  
T.-S. Lin ◽  
S. Kalliadasis
Keyword(s):  
Electric Field ◽  
Bound States ◽  
Stokes Equations ◽  
Travelling Waves ◽  
Film Surface ◽  
Wave Model ◽  
Bound State ◽  
Long Wave ◽  
Finite Set ◽  
Solitary Pulse

The flow of an electrified liquid film down an inclined plane wall is investigated with the focus on coherent structures in the form of travelling waves on the film surface, in particular, single-hump solitary pulses and their interactions. The flow structures are analysed first using a long-wave model, which is valid in the presence of weak inertia, and second using the Stokes equations. For obtuse angles, gravity is destabilising and solitary pulses exist even in the absence of an electric field. For acute angles, spatially non-uniform solutions exist only beyond a critical value of the electric field strength; moreover, solitary-pulse solutions are present only at sufficiently high supercritical electric-field strengths. The electric field increases the amplitude of the pulses, can generate recirculation zones in the humps and alters the far-field decay of the pulse tails from exponential to algebraic with a significant impact on pulse interactions. A weak-interaction theory predicts an infinite sequence of bound-state solutions for non-electrified flow, and a finite set for electrified flow. The existence of single-hump pulse solutions and two-pulse bound states is confirmed for the Stokes equations via boundary-element computations. In addition, the electric field is shown to trigger a switch from absolute to convective instability, thereby regularising the dynamics, and this is confirmed by time-dependent simulations of the long-wave model.

Rogue internal waves in the ocean: Long wave model

2010 ◽  
Vol 185 (1) ◽  
pp. 195-208 ◽  
Author(s):  
R. Grimshaw ◽  
E. Pelinovsky ◽  
T. Taipova ◽  
A. Sergeeva
Keyword(s):  
Internal Waves ◽  
Wave Model ◽  
Long Wave

scholarly journals Gravity currents and internal waves in a stratified fluid

2008 ◽  
Vol 616 ◽  
pp. 327-356 ◽  
Author(s):  
BRIAN L. WHITE ◽  
KARL R. HELFRICH
Keyword(s):  
Internal Waves ◽  
Wave Speed ◽  
Numerical Solutions ◽  
Gravity Current ◽  
Gravity Currents ◽  
Stratified Fluid ◽  
Front Speed ◽  
Long Wave ◽  
Conjugate State ◽  
Energy Conserving

A steady theory is presented for gravity currents propagating with constant speed into a stratified fluid with a general density profile. Solution curves for front speed versus height have an energy-conserving upper bound (the conjugate state) and a lower bound marked by the onset of upstream influence. The conjugate state is the largest-amplitude nonlinear internal wave supported by the ambient stratification, and in the limit of weak stratification approaches Benjamin's energy-conserving gravity current solution. When the front speed becomes critical with respect to linear long waves generated above the current, steady solutions cannot be calculated, implying upstream influence. For non-uniform stratification, the critical long-wave speed exceeds the ambient long-wave speed, and the critical-Froude-number condition appropriate for uniform stratification must be generalized. The theoretical results demonstrate a clear connection between internal waves and gravity currents. The steady theory is also compared with non-hydrostatic numerical solutions of the full lock release initial-value problem. Some solutions resemble classic gravity currents with no upstream disturbance, but others show long internal waves propagating ahead of the gravity current. Wave generation generally occurs when the stratification and current speed are such that the steady gravity current theory fails. Thus the steady theory is consistent with the occurrence of either wave-generating or steady gravity solutions to the dam-break problem. When the available potential energy of the dam is large enough, the numerical simulations approach the energy-conserving conjugate state. Existing laboratory experiments for intrusions and gravity currents produced by full-depth lock exchange flows over a range of stratification profiles show excellent agreement with the conjugate state solutions.

A Whitham–Boussinesq long-wave model for variable topography

Wave Motion ◽  
2016 ◽  
Vol 65 ◽  
pp. 156-174 ◽  
Author(s):  
R.M. Vargas-Magaña ◽  
P. Panayotaros
Keyword(s):  
Wave Model ◽  
Long Wave ◽  
Variable Topography

scholarly journals Far-infrared bands in plasmonic metal-insulator-metal absorbers optimized for long-wave infrared

MRS Advances ◽  
2019 ◽  
Vol 4 (11-12) ◽  
pp. 667-674 ◽  
Author(s):  
Rachel N. Evans ◽  
Seth R. Calhoun ◽  
Jonathan R. Brescia ◽  
Justin W. Cleary ◽  
Evan M. Smith ◽  
...  
Keyword(s):  
Ground Plane ◽  
Wavelength Region ◽  
Wave Model ◽  
Far Infrared ◽  
Resonance Wavelength ◽  
Surface Structures ◽  
Metal Insulator ◽  
Long Wave ◽  
Metal Insulator Metal ◽  
Long Wave Infrared

ABSTRACTMetal–insulator–metal (MIM) resonant absorbers comprise a conducting ground plane, a dielectric of thickness t, and thin separated metal top-surface structures of dimension l. The fundamental resonance wavelength is predicted by an analytic standing-wave model based on t, l, and the dielectric refractive index spectrum. For the dielectrics SiO2, AlN, and TiO2, values for l of a few microns give fundamental resonances in the 8-12 μm long-wave infrared (LWIR) wavelength region. Agreement with theory is better for t/l exceeding 0.1. Harmonics at shorter wavelengths were already known, but we show that there are additional resonances in the far-infrared 20 - 50 μm wavelength range in MIM structures designed to have LWIR fundamental resonances. These new resonances are consistent with the model if far-IR dispersion features in the index spectrum are considered. LWIR fundamental absorptions are experimentally shown to be optimized for a ratio t/l of 0.1 to 0.3 for SiO2- and AlN-based MIM absorbers, respectively, with TiO2-based MIM optimized at an intermediate ratio.

scholarly journals A New Quasi-Horizontal Glider to Measure Biophysical Microstructure

2014 ◽  
Vol 31 (10) ◽  
pp. 2278-2293 ◽  
Author(s):  
Herminio Foloni-Neto ◽  
Rolf Lueck ◽  
Yoshiro Mabuchi ◽  
Hisato Nakamura ◽  
Masakazu Arima ◽  
...  
Keyword(s):  
High Resolution ◽  
Internal Waves ◽  
Chlorophyll A Fluorescence ◽  
Field Experiments ◽  
Density Field ◽  
Velocity Shear ◽  
Length Scale ◽  
Flight Performance ◽  
Fluorescence Sensors ◽  
Horizontal Inhomogeneity

Abstract This study describes the development of a new tethered quasi-horizontal microstructure profiler: the Turbulence Ocean Microstructure Acquisition Profiler–Glider [TurboMAP-Glider (TMG)]. It is a unique instrument, capable of measuring ocean microstructure (temperature and turbulent velocity shear), chlorophyll, and turbidity simultaneously through a quasi-horizontal perspective. Three field experiments were carried out near Joga-shima, Japan, to test the TMG flight performance, and those results as well as comparisons with a laser-based vertical profiler, TurboMAP-L (TM), are described here. The TMG was capable of flying with an angle of attack of less than 25° and was reasonably stable for up to 300 m horizontally over 100-m depth. Some new and relevant empirical results about quasi-horizontal application of high-resolution chlorophyll-a fluorescence sensors are presented. The ratio between the Thorpe length scale and the Ozmidov length scale was used as a tracer to demonstrate that most of the TMG density inversions are due to horizontal variability and not to vertical overturning. These waveform structures are probably due to the horizontal inhomogeneity of the density field and are likely caused by internal waves.

Sign in / Sign up

Export Citation Format

Share Document