Development of the One-Component Diode-Array Velocimeter
VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF AEROSPACE AND OCEAN ENGINEERING
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A new optical flow measurement technique, the diode array velocimeter, has been proposed. A DAV works by timing the passage of seed particles through a small section of a light beam. This is achieved by imaging light scattered by the particles on to one or more photodiode arrays. The arrays have a few carefully shaped elements, the shapes and positions of the elements being used to control the measurement volume geometry and thus select the measurement made. Measurement volumes sensitive to velocity, position and acceleration may be designed. Measurements in highly turbulent and reversing flows are possible. A DAV for one-component velocity measurements has been developed to demonstrate this concept. This device uses a single laser beam to illuminate particles and a photodiode array with two rectangular elements to sense their motion. The sensitivity of this device to electrical noise in the photodiode circuitry is analyzed and found to decrease with reduction in measurement volume size. The angle response is also studied and, depending on the signal processing used, found to be closely cosinusoidal to about 60 deg. Changes to the photodiode array design could substantially increase this limit.
- Electrooptical and Optoelectronic Devices
- Fluid Mechanics