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Autorotation of thin plates

University of British Columbia

A visualization technique is applied to the unsteady separated flow about an autorotatlng flat plate. An unsteady potential model is attempted to predict the pressure loading on the plate as a function of angle of attack. To visualize the flow, a streakline is marked by low density air created by the wake of a heated wire probe. An off-center parabolic mirror Schlieren system detects the density gradient. Due to the highly unsteady nature (in this project, the plate rotates at almost 1,000 r.p.m. for a 10-foot per second freestream velocity) of the flow, high-speed 35mm, single lens reflex shots or 16mm. movie films recorded the image. Timing marks on the movie film provided information of the angular speed of the plate during acceleration to the autorotation speed and at autorotation. The two-dimensional unsteady attached flow model attempts to duplicate the effects of separation by superimposing vortices in the wake, as shown in the flow visualization, and by eliminating terms representing the freestream velocity in the range of 60 to 150 degrees angle of attack.

Text

2011-05-25

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http://hdl.handle.net/2429/34846

Mechanical Engineering

University of British Columbia

Graduate