GB2415164A - Vortex streaming apparatus for reducing hull drag - Google Patents

Abstract

A vortex-streaming marine propulsion system has two aspects; a bow wave-rotating system and a stern wave system, either of which are implemented to reduce hydrodynamic drag by introducing a rotating vortex boundary layer between the hull 130 and the surrounding water. The bow wave system comprises a radial array of flippers 127 oscillating in flow in channels with the outer flow half (counter-clockwise vortices) 126 directed at its outlets to stream over the hull and inner half (clockwise vortex barrels) 134 directed inside the hull to one or more vectored bow thruster nozzles 135 for manoeuvring and or stabilising to control hull pitch and roll with lower energy consumption. The stern wave system consists of a trailing captive flipper (151, Fig 3b) in a flexing manifold cut out from the rear quarter of the hull which is used to provide a pitch-stabilised deck for increased user comfort over a wider range of sea states.

Description

VORTEX-STREAMING MARINE PROPULSION SYSTEM

The present invention relates to a marine propulsion system, and in particular to a system for generating vortex streams in flow to reduce hull drag and pitching over a wide range of sea states.

Such a propulsion system may be used in sea water for producing propeller and wave augmented propulsion, hull vortices and as an alternative to a bow thruster.

Propulsion augmentation and hull stabilization systems for propellerbased marine propulsion systems are known. Most of these absorb more energy from the propulsion system than they contribute, or are dependent on wind. With high performance aquaplaning speedboat hulls, thrust delivery is limited in rough sea states. Thrust cut-outs in the form of ",-plates" are required during stern-slamming and bow slamming increases passenger discomfort further.

Integrated low-drag hull and propulsion systems have not evolved appreciably over the last Century whilst development in other technologies such as materials application has taken precedence.

Any development that leads to commercial exploitation must show a reduction in operating costs.

According to a first aspect of the present invention, a ships vortex streamer unit comprising one or more pivoting flippers, hydroplane cowl outer manifolds, central hydroplanes, wave guides, a hollow ducted ships prow, recessed inlet and outlet manifolds, aft thruster ducts, inner throat manifolds and sprung flap-valves, generates thrust augmentation in a ship and reduces hull drag from the bow when operating with a conventional ships propulsion system.

In a first instance of this aspect, an array of vortex streamer units are arranged radially around the prow and in a second instance linearly along the hull at repeater locations and in a third instance in front of the bows.

In the first instance, the flippers are powered for thrust augmentation and vectoring via the aft thruster ducts at low hull speeds for maneuvering and are non-powered but self- resonating in flow at high speeds. In radial prow deployment the units bisected vortex streams are routed along the outer skins of the trailing hull surfaces via the recessed outlet manifolds, and along the inner skin of the hollow ducted prow to aft thruster ducts. The application of power to the pivoting flipper flexing produces thrust in the outlet manifolds and the ducted aft thrusters which can also be vectored to emulate a conventional bow thruster.

In the second instance, the units are mounted at repeater locations along the hull of the ship to maintain the vortices streaming from the bows. Semi-recessed into the hull, with the central hydroplane forming the hulls inner and outer skins, they consist of inlet and outlet recessed manifolds with an hydroplane outer manifold enclosing the flippers. The counterrotating vortex streams are bisected along the inner and outer hull skins, the inner skin streams being ducted to an aft vectored thruster unit mounted proud from the hull to enhance the trailing vortex streaming and provide hull roll stabilization through its vectoring, the outer skin streams being routed along the outer skin of the hull via the recessed outlet manifold.

In the third instance, the unit produces a vortex stream which is bisected by the central hydroplane into clockwise and anti-clockwise vortex streams which are routed to the port and starboard outer skins of the ships bow and trailing hull surfaces respectively. The flippers are mounted directly in front of the ships bows, the central hydroplanes forming the leading edge of the bows. Multiple units are stacked along the main part of the submerged bows.

According to a second aspect of the present invention, a ships stern wave vortex streamer unit comprising a stern-pivoting wave thruster, an articulating speedboat hull, an articulating cabin and a dual-opposed sliding lever pivoting mechanism creates an improved ride for a 3L given sea-state and wave-augmented thrust. The stern wave thruster consists of a "short engine" of the prior art embedded in a trailing, articulating central hydroplane flipper which acts as a stabiliser and thrust governor in a a choppy sea and reacts with the hull and stern wave to provide assisted propulsion and conserve momentum by reducing hull slamming and interrupted power-delivery.

The present invention will be described with respect to the accompanying drawings in which: Figure 1 shows the first instance in front and side sectional elevations a bow wave vortex streamer unit mounted in the prow of a ship.

Figure 2 shows the third instance of the bow wave vortex streamer unit and second instance of a repeater unit in sectional plan and a side elevation of several repeater units mounted along the hull of a ship.

Figure 3 shows a stern wave vortex streamer in a detail side elevational section and in a mounted side section in a speedboat with dual-lever pivoting stern wave vortex streamer, cabin and articulating hull.

A first example of a vortex-streaming marine propulsion system according to the first aspect of the present invention will be described by figures 1 and 2. In this case, the propulsion system reacts with the bow wave of a ship primarily to reduce hull drag used with a conventional propellerbased propulsion system.

A second example of a vortex-streaming marine propulsion system according to the second aspect of the present invention will be described by figure 3. In this case, the propulsion system reacts with the stern wave of a speedboat primarily to create thrust when used with a flipper-based "short engine" propulsion system.

Figure 1 shows in two sectional side and front elevational sketch views sections "X-X" and "Y-Y" a bow wave vortex streamer as mounted in the prow of a ship forming a radial array l 27. A stream of vortices 126 flows along the hull 130 to reduce the drag in surface water flow 136 imposed on a conventional stern propulsion system. Manifolded flippersl27 resonate in flow to generate streaming vortices in the wake or slip-stream.

The prow of the ship 128 comprises the inner wall of the manifold and a hydroplane cowl comprises the outer wall 129. The hollow prow of the ship 132 forms a duct 133 behind the head of the prow 128 to bisect the counter-rotating thrust vortices from the rotating vortices forming a vortex cushion running outside skin the bow 126. The counter-rotating vortices 134 are lead aft and cancel each others rotation out in the aft thruster duct to create an exhaust flow 135 which is vectored to reduce drag and or create propulsion for maneuvering.

The aft thruster duct 135 is mounted proud from the hulls outer skin 130 to enhance rather than counter vortex streaming 126. The flippers are powered for low-speed maneuvering and self-powering from the flow, acting as stream engines for high-speed operation. The flap valves mounted in the outer manifold cowl 129 enhance vortex stream production along the outer hull skin and reduce drag 136. Recessed outlet manifolds manage vortex flow streaming 126 along the trailing hull 131.

Figure 2 shows in two views figure 2b and figure 2a the second and third instances of this aspect of the invention respectively; a flipper based bow wave propulsion system mounted along the hull and directly in front of the bows. The bows bisect the trailing vortices into clockwise and counter clockwise-rotating streams running along either side of the "steep vee" of the ships bows. Wave guides 138 and repeater units 139, 149 maintain the vortex cushion as the hull passes through the water reinforcing their spinning as they are displaced aft wards along the hulls outer skin. The wave guides direct the flow of vortex streams along s the hull as the steep vee bow curves into a shallow vee at the stern.

Figure 2a shows the repeater units 143, 144 mounted along the hull 142 in sectional side elevation 144 and plan view. The outer hull skin of the ship is cut 146 and recessed 145. The resulting duct 147 transports exhaust counter-rotating vortices to a vent located further aft as described in figure 1. Recessed, tapered inlet and outlet waveguides 148, 149 provide vortex barrel collection and dispersion allowing fewer distributed units to serve a larger hull area 142.

Figure 2b shows single flipper repeater units 139 mounted at intervals along the hull with channels and wave guides 138 to prevent the dispersion of vortex barrels causing a loss of cushioning. The conventional stern propeller-based propulsion system providing the main source of thrust is shown 141. Ducted counter-rotating vortex barrels collected on the inner hull skin 147 are routed to aft-mounted vectored thruster ducts 147. The vectored thruster ducts alter the direction of thrust augmentation when acting as a group of units under central control to counter hull pitch and roll. Mounted proud from the hull on hollow vectored strut hydrofoils terminating in thruster nozzles, thrust losses caused by hull stabilization are compensated for.

Figure 3 shows the second aspect of this invention, a stern-wave vortexthruster that improves performance and ride whilst delivering additional thrust from stern slamming in sea water.

Figure 3a shows in detail sectional side elevation the tapering flexing hydroplane with embedded "short engine" stern wave propulsion system and slider 168. The embedded slider contains a pivot connecting dual-opposed levers 154, 155 to pivots on the articulating cabin and hull respectively.

Figure 3b shows an articulating hull lSO which has a trailing flexing hydroplane 151 attached to its stern via a pivot 152. A pivoting deck and cabin 153 is also attached to the pivot via a series of sliding pivoting levers 154, 155 and linkages which coordinate the movement of the hull, cabin deck and hydroplane relative to each other in such a way to provide sprung-damped resistance of the cabin and deck to bow and stern slamming, averaging-out the effects of each. Twin levers, 154, 155 pivot in a slider and a damped spring 157 provide controlled pivoting of the main components. As the hull encounters an advancing wave it pitches up 156. The stern hydroplane makes an angle with the hull through the pivot and the cabin pitches forward 157 towards the advancing hull reducing the discomfort of bow slamming to the occupants 158. Embedded in the trailing tapered flexing hydroplane is a manifolded flipper-based propulsion system that creates a stream of trailing vortices that are bisected alternately into clockwise and counter clockwise-rotating streams on either side of the flipper creating ripple flexing in the flipper that is made just sufficiently flexible to permit a little of this without compromising the stiffness required to react against the longer stern wave in the hull cavity.

The hull is continued aft of the stern and pivot point in a raised tapered concave cavity 162 forming a partial manifold between the hydroplane and the cavity. As the stern of the boat slams 163 the hydroplane advances and retreats in the raised tapered cavity 164 compressing and expanding the vortex stream present on the upper surface of the hydrofoil. This causes an acceleration and deceleration of vortex migration aft 165 and hence assists even thrust creation and transmission. At the same time, the cabin pivots in between, reducing discomfort from successive bow and stern slamming by averaging out the angular displacements incurred at the pivot between the hull and hydroplane. The hydroplane is neutrally-buoyant to bisect waves rather than ride them. The power unit for the stern wave propulsion system consists of a marine diesel 166 and fuel supply 167 mounted forward in the hull as a counter- balance. The trailing vortex cushion produced on the underside of the hydrofoil reduces drag that would otherwise be imparted to a large, semi- submersible aquaplaning hull footprint.

When travelling at low speed, the pivot extends to allow the hydroplane to lie in the water with adjustments made to the sprung-damped settings 157.

Claims (10)

1. A vortex-streaming marine propulsion unit emits two counter-rotating vortex streams from its ducted outlets which are bisected by central hydroplanes lying in the central axis of the flipper and its manifold comprises one or more pivoting flippers resonating in flow within throat valve manifolds located on or in the hull prow bow or skin, hull wave guides, a hollow dueled ships prow, recessed inlet manifolds, recessed outlet manifolds, aft thruster ducts, vectored duct thruster nozzles, a stern-pivoting sprung-damped trailing flipper hydrofoil, sprung flapvalves mounted and outlet manifold hydroplane cowls, generates thrust augmentation in a ship and reduces hull drag from the bows, generates hull pitch and roll stabilistaion and drag reduction when placed at repeater locations along the hull and generates propulsion and cabin stabilization from an embedded propulsion system when deployed in a speedboat hull within a recessed stern manifold.

2. A vortex-streaming marine propulsion unit as claimed in claim 1 mounted in the hollow ducted prow of a ship in which a radial array of vortex streamer units have their vortices bisected into clockwise and counter clockwise-rotating streams on the inner and outer skins of the prows central radial hydroplane, ducts the vortex streams on the outer skin onto the trailing outer hull skin via outlet manifolds and ducts the vortex streams on the inner skin via aft thrust ducts into vectored thruster ducts.

3. Multiple vortex-streamer units as claimed in claim 1 mounted along the hull of a ship in recessed or semi-recessed inlet and outlet manifolds at repeater locations has inlet and outlet waveguides to extend the manifolds capture range to distribute and gather vortices as they propagate along the outer skin of the submerged hull, a central hydrofoil comprising the hulls inner and outer skins to bisect contra-rotating vortices away from the outer skin to a vectored stub hydrofoil thruster duct mounted proud from the hull which through its thrust vectoring provides hull pitch and roll stabilization countering the losses caused by conventional hydrofoil stabilisers.

4. A vortex-streamer unit as claimed in claim 1 in which one or more units mounted in a vertical stack with their longitudinal central axees aligned with the front of a steep vee ships hull which forms the central hydroplane provides bisected contra-rotating vortex streams along each bow of the ship.

5. A vortex-streaming marine propulsion unit as claimed in claim 1 in which a pivoting stern-mounted trailing hydroplane suspension featuring an embedded "short engine" flipper-based or any other dueled propulsion system driven by an external motive source to include a marine diesel engine and gearbox-driven reciprocating or rotating flexible shaft drive articulating in a recessed pivoting speedboat hull cavity provides through its partial closing and opening against the pivoting hull in its tapered recessed manifold wave and slamming thrust augmentation and regulation.

6. A stern-pivoting vortex-streaming marine propulsion unit suspension as claimed in claim in which one or more tapered flexing central hydroplane flippers flex in a recessed raised stern hull cavity extending behind the heel point of a conventional speedboat steep vee hull forming a tail shaped in shallow vee or flat but also tapered and flexing which in conjunction with an adjustable sprung damped pivot provides effective absorption and damping of stern slamming.

7. A stern-pivoting marine propulsion unit suspension as claimed in claim 5 in which a dual- opposed sliding lever pivot has its slider mounted horizontally on the trailing hydroplane flipper its first lever pivot terminating in the heel point of the hull and its second lever pivot terminating in the central mast attached to the deck and cabin.

8. Any pivoting hull and trailing hydrofoil marine propulsion unit suspension as claimed in claim 5 consisting of pivots, levers, epicyclic gears, springs, flexible or rigid hydrofoils or hulls, dampers or hydraulic actuators.

Amendment to He claims have been filed as follows q Claims - Amended 1. A marine propulsion system comprising: one or more propulsion devices mounted about a ships hull, a means of generating rotating vortex streams which are spun thrust and streamed along the hull in the boundary layer to reduce hydrodynamic drag and provide propulsion.

2. A propulsion device as claimed in claim 1 mounted on the bow of a ship comprising: a hollow ducted prow with one or more vectored duct thruster nozzles, a radially- mounted plurality of aft thruster ducts, central hydroplanes, recessed inlet manifolds, recessed outlet manifolds and pivoted vanes or flippers which convert the ships bow wave and bow slamming into rotating vortices and direct them along the length of the ships hull to reduce hydrodynamic drag thereon.

3. A propulsion device as claimed in claim 2 that provides a means of directing bisected rotating and counter-rotating vortex streams outside and inside said outer hull skin using said central hydroplane mounted in the recessed outlet manifold forming the bows and or the outer hull skin.

4. Propulsion devices as claimed m claim 2 mounted in a modified ships prow, comprising: vectored xlaust thrust nozzles to form a bow thruster, recessed inlet and outlet manifolds, a radially-lounted outer manifold cowl, central pivoting vanes, a central hydroplane.

5. A propulsion device as claimed in claim 1 In which a means of generating vortex streams which are spun thrust and streamed along alternate sides of a central manifold hydroplane one side forming the propulsor stream the other the exhaust stream to include a powered pivoting vane or a powered tapered flexing flipper is provided. 1

5. A propulsion device as claimed in claim 1 mounted in the stern of a ships hull comprising: a stern-pivoting sprung-damped trailing flipper hydrofoil, sprung flap valves mounted on the outlet hydroplane manifold cowls. a plurality of pivoted vanes or flippers, a means of converting the hulls stern wave and stern slamming into rotating vortices, a mcan.s of thrusting said vortices aftward in said outlet manifold to produce wave propulsion augmentation thrust and hydrodynamic hull drag reduction.

7. A propulsion device as claimed in claim 1 mounted as a plurality of units along the hull of a ship comprising: recessed inlet manifolds, recessed outlet manifolds, outer manifold cowls, a plurality of pivoted vanes or flippers which produce spun rotating vortices which stream along the hull to reduce hydrodynamic drag thereon.

8. A votex-streaming marine propulsion system as claimed In claim 6 comprising: a stern-mounted trailing hydroplane, a trailing "long" hydroplane tail, an embedded "short" engine flipper vane or any other ducted propulsor, a motive source for said short engine propulsor to include a marine diesel engine and gearbox-driven reciprocating or rotating flexible shaft drive, a trailing hydroplane hull suspension about which the trailing.cini- submersible hydroplane articulates, a hull stern cavity forming an outlet Landlord, a means of providing propulsion augmentation and thrust regulation through said hydroplanes partial closing and opening in pivoting during hull, stern slamming a gair..t said tapered hull cavity wall.

9. A vortex-streaming n,;,rine propulsion system as claimed in claim 6 comprising: one or more recessed, flexing. tapered raised hull cavities forming an outlet manifold extending beyond flee necl point of an aquaplaning speedboat hull.

10.A speedboat hull as c n!ned in claims 6 and 8 comprising: a "steepvee" bows a "shallow vee" stern. ;r e-ailing central long hydroplane flipper tail pivoting in its suspension, a means of effective absorption damping and thrusting of the stern wave and stern slamming.