Laser Streak Velocimeter for Two-Dimensional Flows in Gases.
Abstract
A new velocity measuring technique, laser streak velocimetry (LSV), was developed for two-dimensional flows in gases. A high power argon ion laser beam was formed into a thin sheet of light to illuminate a two-dimensional plane in the flow around a body. Ten micron sized particles were introduced into the flow, and photographs were taken of the particles as they traversed the light sheet. The length of the streak made by each particle on the photograph was a measure of its velocity since the camera shutter speed was known. The velocity profile in the boundary layer of a flat plate was measured and found to agree within 4% of the theoretical value. Low Reynolds number flow around a circular cylinder was measured, and velocities in the wake were found in close agreement with theory and with previous measurements. A velocity mapping of the non-steady vortex shedding of a Karman vortex street was also made. The flow around a delta wing was analyzed due to current interest in low speed separation. The velocities above the surface of a 60 deg delta wing were measured by LSV, and results were compared to theory. The flow was found to be non-conical, contrary to the assumption of most analytical treatments. Future developments of the laser streak velocimeter were discussed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1976
- Accession Number
- ADA045379
Entities
People
- George William Sparks Jr
Organizations
- Air Force Institute of Technology