High Seas Engineering LLC

Other

Millipore Corporation

Bolt Beranek and Newman Inc.

Bird-johnson Company

Atlantic Applied Research Corporation

Neal A Brown

Cam M Shaar

Victor G Grinius

Anthony J DiLeo

Michael W Phillips

Francesco Lanni

John A Norton

George E Hecker

Michael W Haberland

Philip S Stacy

A marine riser that includes active boundary-layer control ('BLC') for reducing hydrodynamic drag and vortex-induced-vibration ('VIV') caused by currents. The marine riser includes at least one riser pipe surrounded by a BLC sheath. Extending through the sheath is at least one nozzle, preferably at least one pair of slot-nozzles, for discharging water into the sea in which the marine riser is deployed. The BLC sheath may be rotate-able to align a pair of slit-nozzles with the current direction, or in a fixed BLC sheath, pairs of slot-nozzles may be selectively activated based on the current direction. The BLC sheath may also include a tail-jet or retractable tail-fin. The BLC sheath may be formed from telescoping sections that decrease in diameter toward the bottom of the riser and that are nested when the telescoping sheath is retracted. Finally, a BLC system may also be implemented in a production riser system.

System and method for reducing drag and vortex induced vibration in marine applications

A system for reducing hydrodynamic drag and vortex-induced-vibration (&ldquo;VIV&rdquo;) in a bluff hull. In a bluff hull that is designed to be at least partially submerged in a fluid, such as water, the hull has an internal area for holding or transferring fluid. When the hull is beset by a current present in the water, the surface of the bluff hull has an up-current side and a down-current side. The hull surface has at least one opening, preferably a slot-nozzle, for discharging the fluid from the internal fluid area of the bluff hull out of the hull surface and into the surrounding water at a velocity greater than the current velocity, so as to reduce flow separation of the current on the down-current side of the hull surface. Also, preferably, the fluid is discharged out of the opening at an angle substantially tangential to the hull surface at the location of the opening and substantially in the direction of the current.

Vibration and drag reduction system for fluid-submersed hulls

A system for reducing hydrodynamic drag and vortex-induced-vibration ('VIV') in a bluff hull. In a bluff hull that is designed to be at least partially submerged in a fluid, such as water, the hull has an internal area for holding or transferring fluid. When the hull is beset by a current present in the water, the surface of the bluff hull has an up-current side and a down-current side. The hull surface has at least one opening, preferably a slot-nozzle, for blowing the fluid from the internal fluid area of the bluff hull out of the hull surface and into the surrounding water at a velocity greater than the current velocity, so as to reduce flow separation of the current on the down-current side of the hull surface. Also, preferably, the fluid is blown out of the opening at an angle substantially tangential to the hull surface at the location of the opening and substantially in the direction of the current.

An impeller for a marine waterjet propulsion system has blades that are configured to reduce cavitation, vibration, noise and physical damage to the major components of the propulsion system or host vessel of installation. The leading edge of each blade of the impeller is skewed forwardly over at least the outer 70% of its span, the forward skew being maximum at the tip and being not less than 35.degree.. The impeller has a blade area ratio of not less than 1.5. The chord lengths of each blade increase progressively from the point of minimum skew to the tip, resulting in reduced loading in the cavitation critical region. A partial or full tip band may be affixed to the blade tips.

Impeller for marine waterjet propulsion apparatus

A filtration process and apparatus are provided wherein feed fluid to be filtered is introduced into a small gap between two rectangular plates. At least one of the plates supports a porous filtration membrane within the gap. During filtration, at least one of the plates is oscillated to effect a continuously changing gradient of gap width between opposing surfaces of the plate. A permeate is collected and a seal is provided to prevent admixture of the permeate with either feed fluid or retentate.

Vibrationally-induced dynamic membrane filtration

A deterrent system is provided for repelling selected species of aquatic animals from an underwater deterrence zone, for example, from the opening of a municipal or industrial water intake. A conduit for fluid, generally water, has an outlet at the deterrence zone. Intermittent flow means cause one-way fluid flow through the conduit, visiting at the outlet as pulses of fluid alternating with periods of insubstantial fluid flow. The pulses have a volume and flow rate sufficiently in excess of the insubstantial fluid flow to repel the selected aquatic animals from the deterrence zone. The conduit outlet does not serve also as a substantial fluid inlet to the conduit and, rather, the system provides substantial net positive outflow from the conduit outlet over one or more full cycles of the aforesaid pulsed fluid flows alternating with periods of insubstantial fluid flow. Volumetric displacement of water from the deterrence zone can be accomplished without generating a current through the use of an optional inflatable boot or bladder to capture the fluid pulses from the outlet for subsequent recirculation or remote discharge.

Underwater deterrent system

This disclosure is concerned with reducing blade-generated cavitation and accompanying noise in systems such as marine ducted reversible thrusters and the like, by novel techniques including a skew-forward blade configuration at the outer radii and particular blade thickness/chord length ratios associated therewith.

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Lexington, MA, United States of America

Neal A Brown