Nikolay Makarenko

Internal Solitary Waves in a Layered Weakly Stratified Flow

The problem on internal waves in a weakly stratified two-layered flow is studied semi-analytically. 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 the upstream flow.

Internal waves in marginally stable abyssal stratified flows

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 solitarywave regimes can be affected by the Kelvin–Helmholtz instability arising due to interfacial velocity shear in upstream flow.

Velocity and transport of the Falkland Current at 46\hbox {

The structure of the Falkland Current is studied on the basis of a CTD/LADCP and SADCP hydrographic section across the current carried out along 46∘S in November 2016. In the upper 200 m, the maximum velocities based on LADCP reach 57 cm/s, and they are as high as 60 cm/s based on SADCP data. The current is directed to the northeast. At 1500 m the velocities decrease to 10 cm/s. The transport measured by LADCP is 30.9 Sv in the water column up to the bottom. The SADCP transport between 0 and 600 m is 20.7 Sv. It is shown that different means of estimating the velocities of the current result in close values.

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In this paper, we study stratified flows and internal waves in the fracture zones of the Mid Atlantic Ridge. The results of measurements carried out in the 39th and 40th cruises of RV Akademik Sergey Vavilov in the autumn of 2014 and 2015 are presented. Hydrophysical properties of the near-bottom flows are studied experimentally on the basis of CTD- and LADCP profiling. Theoretical analysis involves mathematical formulation of stratified fluid flow which uses CTD-data obtained from field observation in the Vema Fracture Zone region. Spectral properties and kinematic characteristics of internal waves are calculated by finite element method.

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A non-linear problem on steady non-homogeneous flows over an uneven bottom is considered. A semi-analytical model deals with asymptotic solutions of the Dubreil-Jacotin — Long equation of uniformly stratified fluid. Approximate solutions are constructed by the perturbation procedure combined with the Fourier method of modal expansion. Stationary wave patterns forced above the rough terrain of finite horizontal extension are calculated and analyzed.

Stratified flows and internal waves in the Central West Atlantic

The problem on non-homogeneous shear flows over rough terrain is considered semi-analytically. A non-linear model of stratified flow over combined obstacle is constructed in the small amplitude limit for the topography. The method uses a Fourier series in modal decomposition of waves caused by a localized multi-bump obstacle modeling a mountain range. The focus of attention is on the stationary wave patterns formed directly above the mountain range. Wave solutions corresponding to topography with a finite number of peaks are calculated. These solutions predict rigorously the splitting of a near-field flow into separate wave zones having different spatial scales.

Stratified flows over a complex relief

The nonlinear problem on steady stratified flows over complex topography formed by finite number of hills is considered analytically. Asymptotic solutions describing sub-critical near-field flow in the vicinity of obstacles are constructed. The impact of nonlinear effects on the interference patterns of lee waves is discussed.

Structures of lee waves over combined topography

An analytical model of weakly stratified fluid flow over the topography formed by isolated group of hills is considered. The wave solutions for the chain of finite number obstacles are obtained and analyzed. Attention is focused on the wave patterns forced directly over the hills and preceding the regular wave trains downstream the obstacles.