Topic
Propulsion
About: Propulsion is a research topic. Over the lifetime, 24977 publications have been published within this topic receiving 200311 citations.
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TL;DR: This paper investigates a simple propulsion mechanism --an up-down asymmetric dumbbell rotating about its axis of symmetry-- unable to propel in the absence of inertia in a Newtonian fluid, and derives the optimal dumbbell geometry.
Abstract: The fluid mechanics of small-scale locomotion has recently attracted considerable attention, due to its importance in cell motility and the design of artificial micro-swimmers for biomedical applications. Most studies on the topic consider the ideal limit of zero Reynolds number. In this paper, we investigate a simple propulsion mechanism --an up-down asymmetric dumbbell rotating about its axis of symmetry-- unable to propel in the absence of inertia in a Newtonian fluid. Inertial forces lead to continuous propulsion for all finite values of the Reynolds number. We study computationally its propulsive characteristics as well as analytically in the small-Reynolds-number limit. We also derive the optimal dumbbell geometry. The direction of propulsion enabled by inertia is opposite to that induced by viscoelasticity.
54 citations
Patent•
19 Aug 2002
TL;DR: In this paper, a pair of elongated ducts on opposite sides of the vehicle body, and a plurality of powered propellers (or other propulsion units such as jet engines) mounted within and enclosed by each of these ducts were used to produce an upward lift force to the vehicle.
Abstract: A VTOL aircraft (10) (or other vehicle such as a sea vehicle) includes a pair of elongated ducts on opposite sides of the vehicle body, and a plurality of powered propellers (or other propulsion units such as jet engines) mounted within and enclosed by each of the elongated ducts (134a, 13b), such as to produce an upward lift force to the vehicle Each of the elongated ducts has a short transverse dimension slightly larger than the diameter of the blades of each propeller (14, 15) enclosed thereby, and a large transverse dimension slightly larger than the sum of the diameters of the blades of all the propellers enclosed thereby
54 citations
Patent•
01 Dec 1997
TL;DR: In this article, the propulsion motor is connected to receive electric power from the at least one fuel cell stack and is operatively connected to mechanically drive a device for directing a fluid stream into the stack.
Abstract: A fuel cell engine for a vehicle comprises at least one fuel cell stack for producing electric power from a fuel and an oxidant, a propulsion motor, for propelling the vehicle. The propulsion motor is connected to receive electric power from the at least one fuel cell stack and is operatively connected to mechanically drive a device for directing a fluid stream into the fuel cell stack. In preferred embodiments the propulsion motor is operatively connected to drive a device for directing at least one reactant fluid stream into the fuel cell stack.
54 citations
TL;DR: In this article, a case study of a 3.5-kg fixed-wing aircraft with a VTOL propulsion system is presented, where the required battery capacity and total mass are determined from mission analysis.
54 citations
Patent•
17 Mar 2000TL;DR: In this paper, a propulsion system for use in a hybrid vehicle, wherein a first propulsion system provides a driving force to a first pair of wheels and a second propulsion system provided a driving forces to a second pair of wheel, is presented.
Abstract: A propulsion system for use in a hybrid vehicle, wherein a first propulsion system provides a driving force to a first pair of wheels and a second propulsion system provides a driving force to a second pair of wheels. A system controller actuates the propulsion systems determines the necessary commands to be provided to the first and second propulsion systems so as to provide the vehicle with the most efficient driving and/or stopping force.
54 citations