Abstract: A reduced drag surface involves a perforated or porous surface exposed to a flowing fluid and a slip interface disposed between the surface and the flowing fluid, wherein the slip interface is formed from an entrapped fluid trapped at the surface. A method for modifying a drag coefficient on a reduced drag surface involves the steps of supplying a fluid to a perforated or porous surface exposed to a flowing fluid, wherein the surface traps the fluid at the surface to form an entrapped fluid and forming a slip interface between the surface and the flowing fluid, wherein the slip interface is formed from the entrapped fluid. An apparatus for a reduced drag surface includes the reduced drag surface described above and a source of fluid fluidically coupled to the surface such that the source supplied fluid to the surface to form the entrapped fluid.

Abstract: A method of producing a pulsatile jet flow from a substantially constant flow primary jet in a way that is mechanically efficient, easy to implement, and allows direct control over pulse duration and pulsing frequency is disclosed herein. The invention includes at least two components: (a) a constant flow fluid jet produced by any normal method (e.g., propeller) that can be directionally vectored fluidically, mechanically, or electromagnetically and (b) a nozzle with multiple outlets (orifices) through which the vectored jet may be directed. By alternately vectoring the jet through different outlets, a transient (pulsatile) flow at an outlet is obtained even with a substantially constant primary jet flow. Additionally, the nozzle outlets may be oriented in different directions to provide thrust vectoring, making the invention useful for maneuvering, directional control, etc.

Abstract: A method of producing a pulsatile jet flow from a substantially constant flow primary jet in a way that is mechanically efficient, easy to implement, and allows direct control over pulse duration and pulsing frequency is disclosed herein. The invention includes at least two components: (a) a constant flow fluid jet produced by any normal method (e.g., propeller) that can be directionally vectored fluidically, mechanically, or electromagnetically and (b) a nozzle with multiple outlets (orifices) through which the vectored jet may be directed. By alternately vectoring the jet through different outlets, a transient (pulsatile) flow at an outlet is obtained even with a substantially constant primary jet flow. Additionally, the nozzle outlets may be oriented in different directions to provide thrust vectoring, making the invention useful for maneuvering, directional control, etc.

Abstract: A method of producing a pulsatile jet flow from a substantially constant flow primary jet in a way that is mechanically efficient, easy to implement, and allows direct control over pulse duration and pulsing frequency is disclosed herein. The invention includes at least two components: (a) a constant flow fluid jet produced by any normal method (e.g., propeller) that can be directionally vectored fluidically, mechanically, or electromagnetically and (b) a nozzle with multiple outlets (orifices) through which the vectored jet may be directed. By alternately vectoring the jet through different outlets, a transient (pulsatile) flow at an outlet is obtained even with a substantially constant primary jet flow. Additionally, the nozzle outlets may be oriented in different directions to provide thrust vectoring, making the invention useful for maneuvering, directional control, etc.

Abstract: A method of producing a pulsatile jet flow from a substantially constant flow primary jet in a way that is mechanically efficient, easy to implement, and allows direct control over pulse duration and pulsing frequency is disclosed herein. The invention includes at least two components: (a) a constant flow fluid jet produced by any normal method (e.g., propeller) that can be directionally vectored fluidically, mechanically, or electromagnetically and (b) a nozzle with multiple outlets (orifices) through which the vectored jet may be directed. By alternately vectoring the jet through different outlets, a transient (pulsatile) flow at an outlet is obtained even with a substantially constant primary jet flow. Additionally, the nozzle outlets may be oriented in different directions to provide thrust vectoring, making the invention useful for maneuvering, directional control, etc.

Abstract: Measuring mechanical propulsive power includes establishing a first power and a second power. The first power is associated with a first rate of energy conversion by a device in a fluid, where the device is in the wake of a self-propelled conveyance moving with respect to the fluid. The average distance between the device and self-propelled conveyance may remain substantially unchanged. The second power is associated with a second rate of energy conversion by the device in the fluid without the self-propelled conveyance, where the other physical factors are substantially similar to that associated with the first power. The difference between the first power and the second power is calculated. The mechanical propulsive power for the self-propelled conveyance is determined using mappings, where a mapping associates the difference with the mechanical propulsive power.

Abstract: A method of producing a pulsatile jet flow from a substantially constant flow primary jet in a way that is mechanically efficient, easy to implement, and allows direct control over pulse duration and pulsing frequency is disclosed herein. The invention includes at least two components: (a) a constant flow fluid jet produced by any normal method (e.g., propeller) that can be directionally vectored fluidically, mechanically, or electromagnetically and (b) a nozzle with multiple outlets (orifices) through which the vectored jet may be directed. By alternately vectoring the jet through different outlets, a transient (pulsatile) flow at an outlet is obtained even with a substantially constant primary jet flow. Additionally, the nozzle outlets may be oriented in different directions to provide thrust vectoring, making the invention useful for maneuvering, directional control, etc.

Abstract: Measuring mechanical propulsive power includes establishing a first power and a second power. The first power is associated with a first rate of energy conversion by a device in a fluid, where the device is in the wake of a self-propelled conveyance moving with respect to the fluid. The average distance between the device and self-propelled conveyance may remain substantially unchanged. The second power is associated with a second rate of energy conversion by the device in the fluid without the self-propelled conveyance, where the other physical factors are substantially similar to that associated with the first power. The difference between the first power and the second power is calculated. The mechanical propulsive power for the self-propelled conveyance is determined using mappings, where a mapping associates the difference with the mechanical propulsive power.

Abstract: A pump augmentation uses a nozzle output which is controlled in pulses to produce vortex rings and is controlled such that 1 F = Formation ⁢   ⁢ Number = m ρ ⁢   ⁢ A ⁢   ⁢ D = U ⁢   ⁢ t D