The paper discusses the problems associated with the description of the complicated motions of liquid media, which are accompanied by a multi-scale complex of non-equilibrium processes, including relaxation and inertial effects. The approach is based on the nonlocal theory of non-equilibrium transport processes using the methods of cybernetical physics, which allows one to go beyond the limits of continuum mechanics, to describe the self-organization and evolution of dynamic vortex-wave structures during non-equilibrium momentum transport in a liquid. In the framework of this approach, an algorithm is proposed for determining the scale spectrum of dynamic structures formed in non-equilibrium fluid flows due to the conditions imposed on the system by actions from the side of its environment. The temporal evolution of the flow is described using the Speed Gradient principle developed in the control theory of adaptive systems. The control parameters are the average sizes of the dynamic structure of the liquid medium, and the goal function is determined by the maximum entropy that the system can produce under the constraints imposed on it. In this case, feedback is formed between the structural evolution of the system and the dynamics of the flow, which stabilizes the flow regime. Without taking them into account, the evolution of dynamic structures can lead to various types of instabilities and a change in the flow regime. An example is the high-speed Rayleigh flow, where it is shown that, due to the transition to a turbulent regime, the liquid minimizes irreversible loss of mechanical energy.

The results of high-resolving modeling for the surface semidiurnal tide M₂ in the Laptev Sea have been discussed. They are obtained using a high-resolving version of 3D finite-element hydrostatic model QUODDY-4. It is established that the field of isoamplitudes and isophases of tidal elevations closely resembles that incidents to the interference of counter-coming Poincare waves in the southern part of the Sea and similar Kelvin waves in the eastern one. The above field contains 3 real left-rotating amphidromes placed in the first of them and 2 in the second one. The model amplitudes and phases of tidal elevations, maximum and minimum barotropic tidal velocitites, and the direction of rotation of the barotropic tidal velocity are in reasonably good agreement with the available data of in situ measurements. The modeling results are also used to determine the averaged (over a tidal cycle) density of barotropic tidal energy, the advective transport of kinetic barotropic tidal energy, the barotropic horizontal wave flux of potential tidal energy, and the dissipation rate of barotropic tidal energy in the Sea. An estimate for the dissipation time is found. Its comparison with the existing estimate for the World Ocean as a whole shows that the Laptev Sea is one of significant sinks of barotropic tidal energy in the World Ocean.

In the work, based on numerical methods of viscous fluid dynamics, the hydrodynamic interaction of the impeller, guide vanes and the pump-jet guide nozzle were calculated, in addition, the parameters of the hydrodynamic wake behind the submarine body were determined and compared with experimental data. The results of this comparison allow us to conclude about the correctness of the applied calculation model.
The developed method allows calculating the hydrodynamic effects on the elements of the pump-jet propulsion unit under various operating conditions of the impeller. In addition, it is possible to simulate complex unsteady regimes of submarine motion, which, in the process of testing, are associated with considerable technical difficulties. The number of such modes include propulsion reverse of submarine. It is shown that from the point of view of ensuring the parameters of stealth submarine in the hydrodynamic wake, the mode of steady motion of submarine is most preferable. All other things being equal, in a turbulent wake with a zero excess pulse, a faster damping occurs along the wake parameters as compared to a jet in a slug flow (submarine acceleration conditions) or a splatter pattern (submarine braking conditions).
The presented approach allows to increase the efficiency of design work due to a comprehensive multiparameter analysis of the influence of various factors on the hydrodynamic characteristics of the pump-jet propulsion unit and the sign parameters of the submarine.

The results of data interferometric processing of the oceanographic large-scale experiment SWARM-95 on the coast of New Jersey are submitted in the paper. During the experiment, numerous sensors were deployed for registrations of hydrodynamics of water layers. They performed high-resolution oceanographic surveys of intensive internal waves by using conductivity–temperature–depth (CTD) casts and tows sensors. The acoustic component of experiment SWARM-95 is carried out on two stationary acoustic tracks at presence of intensive internal waves. The intensive internal waves led to significant 3D acoustic effects: horizontal refraction of modes and modes coupling. Within framework of experimental data processing the interference pattern of source sound field in receiver is analyzed by holographic processing. In result of holographic processing of interference pattern the two separated sets of spectral spots are obtained. The first set of spectral spots corresponds to sound field in unperturbed waveguide. The second set of spectral spots corresponds to hydrodynamic perturbation of sound field by IIW. The interference patterns of sound field in unperturbed waveguide and its hydrodynamic perturbation are recovered separately by filtering of one set of spectral spots in hologram domain. The transmission function of the unperturbed waveguide and the temporal variability of the ocean environment are restored.

The paper describes a method for passively determining the distance to an underwater source using the curvature of the wave front of the source field in the Fresnel zone. The synthesis of algorithms for the optimal spatial and temporal processing of information from a system of a hydroacoustic receivers providing signal detection and determination of source parameters, as well as observing their location in a given direction sector and range, is based on the likelihood ratio equation. If there is more than one source in the observation area, the detection of a weak signal of interest to the observer and the determination of its parameters can be difficult due to its side field suppression of a strong source, a shift in the estimate and an increase in the fluctuation error. The article discusses the algorithm of rejection of the interfering signal before carrying out the basic procedures of passive sonar, which reduces the influence of a strong source on the evaluation of the parameters of a weak signal. Calculations of the accuracy of distance estimation using the rejection algorithm and without it are given.

This study presents the results of the light attenuation coefficient measurements in the range of 400–800 nm in the waters of Lake Teletskoye, obtained in a summer cruise (19–23 June 2018). During the cruise in various locations, the attenuation coefficient values varied (to the base of natural logarithm) in the range of 0.2–4.4 m^–1 within the stated wavelength range.
The relative spectral effect of the suspended matter was calculated along with the other major optically active components of the lake water: yellow matter, chlorophyll-a and pure water to assess the contribution of suspension to the total attenuation coefficient. Suspended matter spectral contribution to light attenuation at 430 nm wavelength appeared in the range of 2.3–33.4 %, and at 550 nm — 5.9–47.8 %. Optical microscopy was used to determine the particle size distribution and the number concentration of suspended particles. According to the measurements, weight-average particle radii in the water samples varied primarily within the range 0.5–0.8 µm, while the concentrations differed from 0.9∙10⁶cm^–3 to 3.3∙10⁶cm^–3. Particle size distribution was approximated by the Junge function with a determination coefficient from 0.63 to 0.99.

The development of a software package IGWResearch2 is considered in the paper. This package contains numerical models, hydrological data, data preparation tools, analysis tools and observations’ information related to internal waves in the World Ocean. The proposed approach is pursuing a goal to increase research efficiency by automation of routine operations repeatable with every numerical computation run. A new version of the software package was developed. The software structure was changed significantly and extended based on users’ requests. Communication modules for cloud computing and cloud storage were developed. This approach brings the possibility to transfer a computational process from workstations to a dedicated high-performance server. Cloud storage provides an ability for users to exchange numerical results and other data and store their data on the server. The graphical user interface was upgraded. A step-by-step configuration tool for the initialization of numeric models was added. This tool provides an ability to automatically correct user input based on weakly nonlinear theory estimations. New tools for the laboratory of modeling of natural and anthropogenic disasters of NNSTU n. a. R. E. Alekseev services access were developed. They extend the package with web-site based authorization and provide online access to the database of internal waves’ observations. These tools provide information about internal waves’ locations, their types, and dates on the interactive map. A numerical experiment using the software package is presented in the paper.

Marine magnetometers are promising means of monitoring the water area with an estimated presence of potentially dangerous underwater objects. They are successfully used when searching for underwater objects in conditions of the ineffectiveness of sonar tools: in shallow water, in any media (water, soil) and, especially, at the boundaries of these media. As a rule, the search for an underwater object using magnetometric means is carried out along the “meander” trajectory, the main characteristics of which are the search bandwidth (depending on the magnetic characteristics of the underwater object) and the lenth of a searching tack.
An analysis of the development trends of marine magnetometers revealed the following main directions: the expansion of their functional capabilities, the increase in the sensitivity of magnetic field sensors, and the increase in mass and dimensional characteristics. However, in accordance with modern requirements, the main directions of development of marine magnetometry tools have changed radically. It has been established that the process of detecting an underwater ferromagnetic object by mobile magnetometers is stochastic in nature, which is not taken into account by the traditional method of determining the recommended search band for an underwater object, which leads to the risk of missing it. Therefore, the actual problem of improving search magnetometric means is the development of a methodological apparatus for evaluating the efficiency of detection of underwater objects. A new (probabilistic) approach to the information processing algorithm of the magnetometer signal is proposed, which determines the width of the recommended search band of an object with guaranteed values of the probability characteristics of its detection.

A. Velikanov (1879–1964) is known as one of the founders of inland hydrology. In 1917 he began his teaching work at the Tomsk Institute of Technology. Then he obtained a professor’s positions at the Moscow Institute of Surveying in 1921 and at Moscow Technical School in 1923. From 1930 till 1941 he worked as head of the subdepartment stream processes’ dynamic at the Moscow Institute of Hydrometeorology. In 1935, M. A. Velikanov created the laboratory of fluid dynamics at Power Engineering Institute of Soviet Academy of Sciences (from 1947 — laboratory of stream processes at Institute of Geography), which was directed by him until 1952. In 1945, at the Physics Department of Moscow State University, he organized the training process of specialists in the physics of the channel stream. M. A. Velikanov was conceded as the creator of flow stations, which were later developed in the USSR and abroad. In his research, he paid great attention to the physic of stream processes and properties of high turbidity streams.