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Blade Vortex Interaction
A blade vortex interaction (BVI) is an unsteady phenomenon of three-dimensional nature, which occurs when a rotor blade passes within a close proximity of the shed tip vortices from a previous blade. The aerodynamic interactions represent an important topic of investigation in rotorcraft research field due to the adverse influence produced on helicopter noise reduction, rotor noise, particularly in low speed descending flight condition or maneuver, which generates high amplitude Impulse noise (audio), impulsive noise. Classes of blade vortex interactions Literature distinguishes different classes of BVIs in helicopter rotors depending on the impacting vortex axis with respect to the blade span. Generally, It can be divided into four distinct types, which will be described as follows: Parallel BVI Parallel (geometry), Parallel BVI occurs when the vortex and the blade axes are nominally parallel. It is the BVI phenomenon that produces the largest-amplitude impulse noise (audio) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helicopter Blade Tip Vortex Simulation By DLR
A helicopter is a type of rotorcraft in which Lift (force), lift and thrust are supplied by horizontally spinning Helicopter rotor, rotors. This allows the helicopter to VTOL, take off and land vertically, to hover (helicopter), hover, and to fly forward, backward and laterally. These attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft and many forms of STOL (Short TakeOff and Landing) or STOVL (Short TakeOff and Vertical Landing) aircraft cannot perform without a runway. In 1942, the Sikorsky R-4 became the first helicopter to reach full-scale Mass production, production.Munson 1968.Hirschberg, Michael J. and David K. Dailey"Sikorsky". ''US and Russian Helicopter Development in the 20th Century'', American Helicopter Society, International. 7 July 2000. Although most earlier designs used more than one main rotor, the configuration of a single main rotor accompanied by a vertical anti-torque tail rotor (i.e. unicopter, not to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
