EP2029425A2

EP2029425A2 - A method for generating wave motion of watercraft

Info

Publication number: EP2029425A2
Application number: EP07747740A
Authority: EP
Inventors: Michal Latacz
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-05-29
Filing date: 2007-05-28
Publication date: 2009-03-04
Anticipated expiration: 2027-05-28
Also published as: WO2007139408A2; CY1116021T1; PL379796A1; PL215828B1; PL2029425T3; DK2029425T3; EP2029425B1; WO2007139408A3; PT2029425E; ES2530076T3; SI2029425T1; WO2007139408B1

Abstract

The invention refers to a method which consists in that a specific number of elements, hereinafter referred to as the arms (2), are put into motion in the plane perpendicular to the fluid flow direction, and project from the hull of the watercraft at a specific part of their length. Each of the arms (2) is propelled with an individually designated motion generator (3) of a variable amplitude (A) and frequency (f) of displacements, controlled by the electronic central control unit (4).

Description

A method for generating wave motion of watercraft

The present invention refers to a method of wave motion which consists in generating locomotor wave for propelling watercraft.

Currently a number of devices use wave propellers for propelling watercraft, in which liquids are mixed perpendicular to the plane of the elements' oscillation.

A method for fluid flow forcing, as described in US3620651, which uses the surface propeller, properly attached and connected with the motion generator through a system of levers, and which causes sinusoidal form of the function of location thus forcing the flow of fluid in the direction perpendicular to the plane of the oscillation. A motion generator, common for the entire system, is a crankshaft of a constant

crank value. A method of generating locomotor wave enables change in

operational frequency but it does not enable independent change of constituent amplitudes. US3435800 description refers to a method for

fluid flow forcing using a waving propeller between the hulls of a catamaran boat. In this solution, a hydraulic system is used for forcing wave motion of the surface propeller, which comprises a constant discharge pump, a multi-piston distributor and a system of two layers of channels located inside the surface propeller, which constitute a motion generator. A working agent is alternately forced in and pumped out from them. Such operation results in fluctuation of stresses inside the channels, and thus local distortion of the element. As a result of proper sequence of the local distortions, wave motion of the entire surface propeller is generated. As distributor pistons are driven by a single crankshaft, they have a constant stroke, hence it is only possible to change operational frequency. RU2009958 description refers to a method for fluid flow forcing, which uses a surface propeller comprising a set of rigidly attached deformable arms connected with a membrane. Only the first arm is connected to the generator. And it is only possible to change operational frequency of the system. A method for fluid flow forcing is also known from US5611666, which is similar to aforesaid one, and the

difference is a mechanism comprising many tightly deployed arms, which interact with one another and thus force locomotor wave generation in the direction perpendicular to the plane of their oscillation. The wave motion of the arms is generated by progressive motion of cam-like controlling rollers. Similarly, this method enables only a change in the operational frequency of the system as motion of all arms is forced by a common roller of constant geometry. ES2170004 description refers also to a method for fluid flow forcing, which consists in generating motion of a set of arms connected with a flexible membrane constituting a surface propeller. A motion generator in this case is a camshaft, and here it is again possible only to change operational frequency of the system.

A method for generating flow motion of watercraft referred to in the present invention uses, similarly to aforesaid solutions, motion generation in the plane perpendicular to the direction of fluid flow, generating motion of a certain number of arms (2), which at a part of their lengths project from the hull of the craft, and to which the surface propeller (1) is attached. The present invention consists in that each of the arms (2) which moves in a self-aligning or reciprocating manner, is propelled with an individual generator (3) such as linear induction motor, hydraulic or pneumatic actuator or muscle and the like. A single motion generator, controlled by the electronic central control unit (4) can change amplitude (A) and displacement frequency (f) in a smooth manner. Advantageously, the arms (2) connected with the surface propeller (1) generate a locomotor wave of changeable characteristics, so that the

value of the ratio of the neighbouring amplitudes (A) at a given time ranges from 1 to 2. Advantageously, the ratios (s) between any amplitudes (A) are proportionate to the ratio of any words in the sequence: 1, s, s², s³, sⁿ, ..., wherein sⁿ = s^{n l} + s^n"2. An outline of the contour of the surface propeller may be curve-shaped, symmetric to the symmetry axis (9) of the propeller (1), which is shown with a solid line (10) in figure 6. Such geometry of the propeller makes the propelling mechanism of the watercraft equally efficient in terms of its hydrodynamics, regardless of the movement direction.

The solution according to the present invention forces the wave flow of fluid, which in combination with a system of independently movable, self-aligning or reciprocating elements constituting a single and flexible set of structural elements, enables generation of the locomotor wave. The parameters of the wave, i.e. amplitudes or particular arms peaks and operational frequency, may be modified as a function of the fluid flow velocity lengthways the propeller, in real time, in a constant and independent manner. The result of controlling the wave characteristics and specific geometry of the propeller is security of the laminar flow of

fluid along its surface and ensuring optimum parameters of the locomotor wave, resulting from the mechanics of a given fluid, wherein the parameters comply with the required fluid flow velocity after the surface propeller is properly immersed in the fluid, which hence ensures improvement of the hydrodynamic efficiency rate.

A method according to the invention is explained on the basis of a

description of how a sample watercraft (shown in the figure) solution works and what its structure is. Figure 1 — a perspective projection of a single propelling device; figure 2 - one of the methods for the layout of two surface propellers in watercraft; figure 3 — geometry of the locomotor curve at a moment of accelerating the watercraft from zero velocity; figure 4 - geometry of the curve at the moment when the watercraft reaches an average progressive velocity; figure 5 — geometry of the locomotor curve at the moment when the watercraft reaches its maximum progressive velocity; figure 6 - contour of the surface propeller in the horizontal projection; figure 7 - possible configuration options for the propeller of a single and double hull watercraft and submarine. A method of controlling the propulsion was shown based on the propelling system with the self-aligning arms, as shown in figure 1. In the option shown, the surface propeller is a flexible rubber membrane connecting

particular arms (2). The water is relocated perpendicular to the plane of

arms (2) oscillation. Hydraulic bilateral actuators were used as motion

generators (3). Each generator (3) is connected with two independent distributors (7). The system is equipped in the overflow tank (6) and the constant discharge pump (8), which delivers the working agent parallel to all generators (3). Change in the characteristics of the locomotor waves, which is shown notionally in figures 3, 4, and 5, is obtained by means of changing the opening time of distributors (7) valves, controlled by the electronic central control unit (4). The software controlling the operation of distributors ensures selection of wave characteristics depending on the velocity of the watercraft required by the operator as

well as the current velocity of the watercraft. If velocity of the watercraft increases from zero, i.e. when the watercraft starts moving, wave amplitudes (A) are relatively high and operational frequency of the system is low, as shown in figure 3. When progressive velocity increases, amplitudes (A) of the motion of particular arms (2) decrease and frequency of the entire system increases, which is shown in figure 4, until it reaches the maximum value, as shown in figure 5, when operational frequency reaches its maximum value. The values of neighbouring amplitudes (A) of the locomotor wave at a given moment are not constant but they increase with the distance from the head of the system towards its centre, in a manner described in dependent claims 2 and 3, and shown in figures 3, 4 and 5. Symbol Vc refers to relative liquid flow velocity, and symbol Vp refers to an absolute progressive velocity of the watercraft.

Claims

Patent claims

1. A method for generating wave motion of watercraft which consists in that a specific number of arms (2) are put into motion in the

, plane perpendicular to the liquid flow direction, and at a certain part of their length project from the hull of the watercraft, and to which the surface propeller (1) is attached, characterised in that each of the self-aligning or reciprocating arms (2) is propelled with

an individual generator (3) of a variable amplitude (A) and frequency (f) of displacements controlled by the electronic central control unit (4).

2. A method as claimed in claim 1 characterised in that the arms (2) generate the locomotor wave of variable characteristics, wherein the ratio (s) between the currently neighbouring amplitude (A) of the wave ranges from 1 to 2.

3. A method as claimed in claim 1 or 2, characterised in that the ratios between any amplitudes are proportionate to the ratios between any words in the sequence: 1, s, s², s³, sⁿ, ..., wherein sⁿ = s^ + s"-².

4. A method as claimed in claim 1, characterised in that an outline of the contour (5) of the surface of the propeller (1) is curve-shaped when the arms (2) are located in the same plane. A method as claimed in claim 4 characterised in that an outline of the contour (5) is symmetric to the symmetry axis (9) of the propeller (1).