Actual problems of the theory of surface waves, tides, interactions between waves and barriers and also the development of hydroacoustic detectors are considered. The numerical scheme based on non-orthogonal curvilinear coordinate system is developed for modeling of three-dimensional potential waves. The results of experimental and theoretical (numerical) researches of the interaction between waves and short vertical walls have been analysed. On the basis of modeling of surface semidiurnal tide the energetic characteristics in the Canadian Arctic Archipelago including the system of Hudson Bay are estimated. Data of calculations of the hydrodynamic forces developed by a wing at any phase shift between linear and angular fluctuations of a flat rigid wing are provided. The possibility of use of the principles of an adaptive filtration at realization of the interferential detector of moving underwater objects is discussed. The effective time-domain adaptive noise canceller is offered.
The issue presents the materials of round-table discussion «Fundamental Science to The Navy» which was held within the International Maritime Defence Show in 2013 (IMDS-2013). The directions of fundamental, expected and pilot researches, the development of the latest technologies provided by them are discussed. The innovative potential for development of arms and technical means of the Navy and the directions of realization of military-technical policy of the State are considered. Series of articles showing modern researches in hydroacoustics is presented. The new abilities for long range ocean monitoring arising with underwater parametric array application are discussed. The advanced methods and algorithms of digital space-time signal processing in multi-channel sonar systems for monitoring the underwater situation in sonar complexes of various purposes are considered. The evaluations of energy transmission rates of hydroacoustic information and control networks are shown. The practical recommendations to produce remote control system for underwater vehicle and its navigation are given.
The issue presents review and analysis of few-parameter optical models of seawater inherent optical properties; correlational and structural models are considered, their possibilities, disadvantages and range of application are shown. The estimation of the geostrophic water transport by the Antarctic Circumpolar Current through the Drake Passage in December 2003 on the basis of full-size measurements is given. The results of satellite and field observations are discussed to study submesoscale dynamical processes and phenomena in the White Sea associated with internal waves, eddies and frontal features. The onset mechanism of self-oscillations of mast hoisting gears related to their non-linear hydrodynamic characteristics as well as the action of external periodic forces on this self-oscillating system caused by the vortex separation is considered; mast hoisting gear amplitude-frequency characteristics in the resonant area are plotted. The methods of design technique and future proof scheme of the ship pipe anti-noise tool is discussed; the new method of pressure pulsation dampener design is presented. The features of practical implementation of the holographic method of the acoustic field recovery and visualization of the sound source in the space of the waveguide, which is the method of the matched field processing, as well as the theoretical basis of the method are considered. The results of computational experiments on the study of the effectiveness of the method in the conditions of an inhomogeneous underwater environment are given.
The issue presents papers about theoretical and experimental investigations of surface and internal waves, hydroacoustic and marine optics subjects are consid-ered. Based on numerical solving of stationary one-dimensional potential equa-tions in conformal coordinates the main properties of Stokes waves for the case of optional depth are analyzed. The derivation of the fifth-order Korteweg—de Vries equation is presented for internal waves in two-layer fluid with surface tension on the interface between the layers. The results of level rise simulation in the Gulf of Finland during the passage of the extreme and really observed cy-clones over the Baltic Sea taking into account the operation of St.-Petersburg Flood Protection Barrier are discussed. Characteristic features of lidar images of nonlinear internal waves are calculated and analyzed using actual profiles of hy-drooptical and hydrologic data obtained in the Barents Sea at the presence or absence of current in upper layer. A new method for determining the wave spec-trum based on the distribution of number and sizes of the Sun glints on the rough sea surface is proposed. On the basis of review of ice, snow and oil optical prop-erties the analysis of the possibility of detecting oil pollution on the lower ice/water boundary is presented. A method of modeling of signals of compo-nents of the velocity vector sensor that is placed in the stream consisting of whirls with different sizes and oriented along and across the flow is suggested. The results of syntheses of optimal maximum likelihood automatic target recog-nition algorithm based on amplitude modulation of their signals are shown.