SOVIET NAVAL DEFINITIONS
Submarine Screen
SUBMARINE SCREEN (Zavesa podvodnykh lodok), one of the forms of tactical alignment (of a hunting or battle formation) of submarines in their accomplishment of a common combat mission. The regulated positioning and order of coordinated submarine maneuvering in the screen increase the probability of detecting and attacking the enemy, help attain tactical coordination, and increase safety against mutual destruction. Depending on the purpose, the following submarine screens are distinguished: attack screens, assuring delivery of an attack by the largest possible number of submarines in the screen; reconnaissance screens, ensuring high probability of detecting the enemy and the subsequent guidance of other forces to him; and reconnaissance-attack screens, permitting an optimum combination of accomplishment of reconnaissance missions and a subsequent attack on the enemy by the screen’ s submarines. The alignment of the submarine screen includes establishing coordinates of the oenter of the screen, and designating soreen formation (line abeam, quarter line of bearing, wedge), distance between and adjacent submarines, submergence depth, and so on. Coordinated maneuvering is achieved by establishing the screen’s heading, lap duration, general speed on the lap, time for beginning movement in the screen, and other elements. Control, movement, and vectoring of the submarine screen to the enemy is supported by information passed from shore or shipboard oontrol stations. Operations of submarine screens were employed widely by the command element of the fascist German fleet against allied convoys in the Atlantic, as well as by fleets of other states during World War II. Submarine screens retain their significance under present-day conditions. (Soyetskaya yoyennaya entsiklooediya, Vol 3, 1977, p. 359. USSR)
UNDERWATER FLIGHT
by
V. Voskresenskii, 1976
Up to the present time, man has not experienced any economic need to accelerate underwater speed. Exploratory devices probing the depths of the World Ocean move at a speed of less than 10 kmlhr, and their mobility is further reduced with depth. Although the “speed ceiling” underwater is approximately 100 kmlhr, the speed of the fastest submarines does not exceed 50-60 kmlhr for a number of reasons.
Today there are two distinct types of autonomous bodies: living creatures, created by nature, and transport equipment, created by man.
An interesting picture is formed of the competition between hydrocraft and hydrobionts (creatures living in water). The maximum speed of sailfish and certain species of squid (100-120 kmlhr} is still not attainable for bydrocraft and cannot be explained from the standpoint of modern hydromechanics.
At the present time, studies conducted on animal motion have revealed the possibility of effecting an energy analysis of autonomous body motion, in particular, a comparative analysis of the motion specific to hydrocraft and hydrobionts. Such an analysis will be useful in predicting future underwater transport technology.
In order to achieve high speeds at large depths with good economy, the future designers of underwater devices will have to depart from the traditional scheme: body of fixed configuration ther~omechanical engines and steadily rotating (steady-flow) propellers — and turn to bionic systems, simulating specific locomotor mechanisms peculiar to living inhabitants of the undersea world. The simulation of squid motion looks especially promising since this “live underwater missile” is similar in structure to modern engines and propellers.
What are the most likely operating principles of bionic underwater locomotor systems? They are as follows:
- cybernetic control of interaction between body and medium;
- pulsed operating conditions of locomotor organs;
- developed resistance-reduction mechanisms with local “regulation” of the physical properties of water.
We can assume that, in future high-speed hydrocrart, the flow acceleration function will be carried out by a working propeller. Various types of devices will be able to effect resistance reduction. The technical bases for the creation of such systems — new energy sources, pulse engineering, synthetic materials, etc. — are either available or “on the way in” from scientific theory to engineering. Over the last few years a strong trend has been observed in hydrodynamics towards the study of nonstationary regimes of interaction between bodies and continuous media in order to develop hydropulse devices, et al.
At the present time, the problem of motion pulse has only been tully resolved in the animal world, and most effdotively in cephalopods or fishes. Research on this type or motion are gradually bringing hydrobionic specialists to a more profound understanding of the mechanisms involved in the motion of marine dwellers, in particular to a solution of the mystery surrounding under-water flight and to the possible realization of its technical simulation.
The symbiosis of hydrobionic principles of motion and the latest technical advancements evidently makes it possible to design ultra highspeed underwater devices which attain speeds of about 300 km/hr and up. Furthermore, several major hydrobionic laboratories in Europe and the United States have already been working for a few years on the problems of underwater travel at speeds of up to 400 kmlhr.
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The perturbed volume of water is many times greater than the volume of the hydrocraft. The jet stream, creating a thrust, utilizes a negligible part of the volume of the perturbed medium. The stream has constant acceleration since it is ensured by the steady rotation of the screw propeller. The body does not take part in the creation of a jet stream, and has a fixed configuration. The hydrocraft moves at a constant speed. An energy-flow diagram for the “bydrocraft-perturbed medium” system is shown.
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Kinetic and information e~1ergy enter the system from the side or the engine. The information processes are poorly developed and unilateral in nature. The processes involved in creating thrust and overcoming resistance occur separately. Most or the kinetic energy is spent on idle perturbation of the medium — while part of it is converted into useful work ror effecting hydrooraft motion. Some of the information energy, together with the energy of thermal and structural fields leaves tbe system in a form which creates irregularities in the surrounding medium. An increase in hydrocraft speed produces a sharp drop in the kinetic efficiency of the “hydrocraft-perturbed medium system.”
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The perturbed volume of water is of the same order ot magnitude as the body volume of the hydrobiont. The jet stream utilizes most ot the volume of perturbed medium. The acceleration ot the stream is variable since it is ensured by vibratory body motion. A large portion of the ·length of the hydrobiont varies only slightly, whereas the width of its projection on a plane perpendicular to the direction of motion varies significantly. The hydrobiont moves at variable speed, and changes in the latter are determined by the discrete operation of its locomotor complex.
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A large portion of the inner mantle surface of the hydrobiont takes part in the creation of a jet stream. Body configuration undergoes cyclic variation during motion. In other respects, the motion of squid is similar to that of swordfish.
Bioenergetic and neuroreceptor processes ensure entry of both kinetic and information energy with developed feedback into the system. The creation of thrust and the overcoming of resistance exerted by. the medium. form a single process. Information flow ensures the circulation of kinetic energy between body and medium; hardly no kinetic losses are observed in the system. Total energy losses are represented as a fluctuation function, similar to Figure 2. Kinetic efficiency of the “hydrobiont-perturbed medium” system may also remain high at speeds which are unattainable by modern hydrocraft.
