A Simple Method of Adapting a Wind Tunnel Schlieren System for Interferometry,
Abstract
A simple method of adapting a wind tunnel Schlieren system for interferometry is described. This new interferometer arrangement employs a laser light source, a lens which splits off the reference beam after test beam expansion and a lens and Lloyd mirror to recombine the two beams. The reference beam passes through the test section but is contracted to a narrow waist and displaced well away from the model location. The proposed design combines a number of favourable characteristics which render it particularly useful for wind tunnel tests. These characteristics include: simplicity, optical robustness, low vibration sensitivity, modest coherence requirements and ease of interferogram analysis. The main disadvantage is that slightly less than half of the total field of view can be recorded on a single interferogram. Interferograms obtained from tests on a prototype instrument based on a Schlieren system of low mechanical rigidity are presented. Also included is a comparison between aerofoil pressure distributions obtained by direct measurement and by interferogram analysis. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1978
- Accession Number
- ADA067233
Entities
People
- N. Pollock