RU2389635C2 - Method to destruct hummocked ice cover - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to water transport and can be used to destruct hummocked ice cover. Proposed method consists in attacking said cover by gravitation waves from ship running along ice cover edge. Ship moves in circles nearby ice edge with speed corresponding to maximum wave resistance and with period equal to critical period of flexure-gravitation waves in ice cover. Said method can be implemented with the help of amphibious air-cushion ship.

EFFECT: preventing flooding during hummock formation on rivers.

Description

The invention relates to shipbuilding, in particular to methods for breaking the ice sheet.

A known method of destruction of the ice cover, which consists in the impact on the ice cover by gravitational waves from going along the edge of the ice cover of the vessel, which is additionally subjected to artificial rolling (RU 2081025 C1, 10.06.97).

The disadvantage of the solution is the impossibility of its implementation in narrowness and in shallow water, i.e. in such sections of rivers, where the probability of occurrence of congestion is highest. In bottlenecks, the vessel is not able to move along the edge of the congestion, usually oriented perpendicular to the coastline, for a certain time, sufficient to excite gravitational waves of maximum amplitude. The limited depth also often makes it impossible to use for the implementation of the method of icebreakers. In addition, the movement of masses of ice after the destruction of the congestion can lead to damage to the ship's hull or its discharge aground or shore.

The essence of the invention is to increase the destruction efficiency of the humidified ice cover in this section of the river.

The technical result obtained by the implementation of the invention is to prevent destructive floods in the area of congestion.

The essential features characterizing the invention.

Restrictive: the method of destruction of the ice cover, which consists in the action of gravitational waves on it from the vessel running along the edge of the ice cover.

Distinctive: the vessel is moved along a circular path near the ice edge with a speed corresponding to the maximum wave resistance and a period equal to the critical period of the bending-gravitational waves in the ice cover, and the method is carried out using an amphibious hovercraft.

It is well known that during spring ice drift in narrow places, on sharp bends of river channels and in front of hydraulic structures, the probability of congestion is quite high, while behind the lower edge of the river, as a rule, ice-free sections of water form. This allows you to use the proposed method.

(где: g - ускорение силы тяжести, Н - глубина воды). Этому же значению равна и критическая скорость C_P при распространении свободных игибно-гравитационных волн (ИГВ) в ледяном покрове на мелководье (2. Хейсин Д.Е. Динамика ледяного покрова. Л.: Гидрометеоиздат. 1967. - 216 с). В работе [2] на стр.57 также отмечается, что если критические периоды ИГВ близки к периоду гравитационных волн на чистой воде, то это приводит к эффективному (резонансному) раскачиванию ледяного покрова и взлому припайных льдов.It is also known (1. Kostyukov A.A. Water resistance to ship traffic. L .: Shipbuilding. - 1965. - 448 s), that in shallow water the critical speed is v _K , i.e. the speed of the vessel, at which the wave resistance reaches its maximum value, is equal to

(where: g - acceleration of gravity, N - water depth). The critical velocity C _P during the propagation of free igibno-gravitational waves (IGW) in the ice cover in shallow water is equal to the same value (2. Kheisin D.E. Dynamics of the ice cover. L .: Gidrometeoizdat. 1967. - 216 s). In [2] on page 57, it is also noted that if the critical periods of the IGW are close to the period of gravitational waves in pure water, this leads to an effective (resonant) swaying of the ice cover and breaking of fast ice.

The invention is as follows. An amphibious hovercraft (SVP) is delivered to the area of the resulting jam to its free edge. Since the vessel’s movement on iced ice is unsafe due to the high probability of damage to the skirt, SVPs in the immediate vicinity of the edge of the humidified ice cover in clean water begin to move along a circular path at a critical speed

(where D is the cylindrical stiffness of the ice sheet; ρ _l is the density of ice; h is the thickness of the ice sheet). This will lead to the equality of the frequencies of gravitational waves excited with a maximum amplitude, the critical frequency of the IGW, because their propagation speeds are the same. As is known, the coincidence of the frequency of forced oscillations, i.e. frequencies of gravitational waves, with their own, i.e. critical frequencies igv, leads to resonance. In our case, to the resonant swaying of the flooded ice cover, and as a result, to an increase in the efficiency of its destruction.

To ensure the equality of these periods, the diameter of the circular trajectory (circulation) f is determined by the dependencies:

Insofar as

Such a movement of SVPs is continued (repeated) until the amplitude of the excited IGW reaches its maximum values and the edge of the humidified ice cover begins to collapse.

The implementation of this method will achieve the claimed result.

Claims (2)

1. A method of destroying an iced ice cover, which consists in exposing it to gravitational waves from a vessel traveling along the ice sheet edge, characterized in that the vessel is moved along a circular path near the ice edge with a speed corresponding to the maximum wave resistance and a period equal to the critical period of bending -gravity waves in the ice cover. 2. The method according to claim 1, characterized in that it is carried out using an amphibious hovercraft.