INFLUENCE OF ACOUSTIC PRESSURE WAVE ON THE MOVEMENT OF THE UNDERWATER

The forced movement of the submarine under the action of an acoustic pressure wave at rectilinear and uniform movement of the device is analyzed. The analysis of the dynamics of translational movement of the hull under the action of an acoustic pressure wave in an ideal environment, which makes it possible to assess the physical properties of the environment and the elastic properties of the outer hull on the value of the maximum movement of the submarine. It is proved that if the total pressure pulse is limited, then the water particles will receive certain displacements and it can be expected that under these conditions the displacement of the submarine will be determined. The results of the analysis make it possible to conduct a comparative analysis of the translational movement of the submarine under the action of an acoustic pressure wave, taking into account the characteristics of the moving medium, more precisely, taking into account the viscosity of the real medium

ՏՈՆԸ ԱՌԱԾԱՅԻՆ ԼԵԶՎՈՒՄ

In the Collection of Armenian proverbs by Aram Ghanalanyan the proverbs in which the Armenian traditional holidays are mentioned constitute a certain number. We suggest uniting in two groups the proverbs, which have holiday references, diffused in different thematic sections and chapters, as well as in the appendices of the collection of proverbs. These two groups include: sayingsproverbs, which are based on a) interrelation of the time and holiday, and b) one or another attribute of the holidays. In a part of sayings-proverbs, referring to time, the question is directly about the time in the semantic context, according to which everything has its time. In case of other proverbs, the question refers to the seasonal-climatic changes of the time. The latter are based on the folk ecological knowledge, preserved in the feast tradition. In this group of proverbs the holidays play a role of the real medium of time calculation. The following series of proverbs present primary associations, connected to the feast, specific descriptors of the holidays, which are, as a rule, more connected to their external, secular, rather than deep mythological aspect.

Effect of Acoustic Shock on Submarine

The carried-out analysis of the dynamics of a submarine body’s translational motion affected by an acoustic shock in the ideal medium provides for the possibility to evaluate the physical properties of the medium and elastic properties of the external body of the submarine to the value of limited motion of a submersible vehicle. The results of analysis provide for the possibility to conduct a comparative analysis of the submersible vehicle’s translational motion affected by an acoustic shock, taking into account the peculiarities of the motion medium, or rather taking into account the viscosity of the real medium. In this work, evaluative measurements of the features of moving the layout of the submarine were carried out. The limiting values of the displacement of the layout of the submarine are established for the case of the presence of an external artificial diffuse disturbance. A fluid with air bubbles from a compressed air cylinder was used to create an artificial diffuse perturbation. Such conditions are possible with intensive local bombardment or the presence of other high-speed underwater vehicles involved in local underwater operations.

Economical connections between several European countries based on TSP data

A fluent economical collaboration between countries is a major need. European flows of trade and people are supported by efficient connections between main localities from a geographic region, in many cases overriding national borders. This paper introduces three traveling salesmen problem instances based on freely available geographic coordinates of the main cities of France, Portugal and Spain. These instances are unified, generating other four larger instances: three with all pairs of countries and one instance with the settlements from all the three countries. The study includes an analysis of quality of solutions for a version of branch & cut algorithm and some hybrid heuristics including the Lin–Kernighan algorithm. $Bor\mathring{u}vka$, Quick$Bor\mathring{u}vka$ and Greedy algorithms are also used in the hybrid approaches in order to obtain a potential beneficent initial solution for the Lin–Kernighan algorithm. Concorde solver, nowadays state-of-the-art exact software, together with the already mentioned algorithms, is used to test and furthermore analyze the new TSP instances. Some results are represented using online services such as Google Maps, showing the potential integration of the Concorde’s optimum results into commercial routing applications. The very good results provided by the Lin–Kernighan method allow its usage for real medium-sized routing instances.

Converging Cylindrical Symmetric Shock Waves in a Real Medium with a Magnetic Field

The topic “converging shock waves” is quite useful in Inertial Confinement Fusion (ICF). Most of the earlier studies have assumed that the medium of propagation is ideal. However, due to very high temperature at the axis of convergence, the effect of medium on shock waves should be taken in account. We have considered a problem of propagation of cylindrical shock waves in real medium. Magnetic field has been assumed in axial direction. It has been assumed that electrical resistance is zero. The problem can be represented by a system of hyperbolic Partial Differential Equations (PDEs) with jump conditions at the shock as the boundary conditions. The Lie group theoretic method has been used to find solutions to the problem. Lie’s symmetric method is quite useful as it reduces one-dimensional flow represented by a system of hyperbolic PDEs to a system of Ordinary Differential Equations (ODEs) by means of a similarity variable. Infinitesimal generators of Lie’s group transformation have been obtained by invariant conditions of the governing and boundary conditions. These generators involves arbitrary constants that give rise to different possible cases. One of the cases has been discussed in detail by writing reduced system of ODEs in matrix form. Cramer’s rule has been used to find the solution of system in matrix form. The results are presented in terms of figures for different values of parameters. The effect of non-ideal medium on the flow has been studied. Guderley’s rule is used to compute similarity exponents for cylindrical shock waves, in gasdynamics and in magnetogasdynamics (ideal medium), in order to set up a comparison with the published work. The computed values are very close to the values in published articles.

State Estimation and Determination of Flexibility Potential in Medium Voltage Networks*

This paper describes how flexibility of medium voltage systems can be used for operation of high voltage systems. This is explained using the example of a congestion management system for high voltage networks developed in the research project IDEAL. First, it is explained to what extent flexibility is required for high voltage system operation. After that, the entire congestion management system with flexibility of medium voltage systems is presented. Then, methodology for observability analysis, state estimation and determination of flexibility potential is shown. Finally, the implementation of the methodology in two real medium voltage systems is described.