A synchronous strobed laser light sheet for rotor flow visualization

摘要

A synchronous strobed laser light sheet generator was designed and used for flow visualization of a helicopter rotor model. The laser light sheet strobe circuit was designed to allow selectable blade position viewing, strobe duration, and multiple pulses per revolution for rotors having 2 to 9 blades. A slip-sync mode permits slow motion visualization of the flow field over complete rotations of the rotor. The design was tested at NASA Langley Research Center's 14 by 22 foot subsonic tunnel where the flow was seeded with propylene glycol smoke. Between runs, a calibration grid board was placed in the plane of the laser sheet and recorded with the video camera at the position used to record the flow field. The system was used to make 2-dimensional flow field cuts of a four-bladed rotor operating at wind tunnel speeds up to 79.25 meters per second (260 feet per second).