Pressures on a Slender, Axisymmetric Body at High Angle of Attack in a Very Low Turbulence Level Air Stream.
Abstract
The report describes experimentally measured transient pressures at low speeds on a model consisting of a circular cylinder with four different interchangeable tangent ogive noses in the angle of attack range from 30 to 90. Great care was taken to eliminate extraneous disturbances: a wind tunnel with an extremely low level of free stream turbulence (approx. 0.01%) was used, the model was rigidly mounted and efforts were made to ensure laminar separation without turbulent re-attachment. By comparing the results with those obtained previously on the same model in similar tests at a higher level of free stream turbulence (approx. 0.7%) it is shown that there is a dramatic reduction in unsteadiness in the low turbulence level air stream and switching of the flow pattern is virtually eliminated. However, it is also found that the mean unswitched level is dependent on the roll angle of the model and hence that strict control of the free stream conditions is not sufficient to guarantee results which are independent of the experimental equipment. Details of the inherent unsteadiness present in the flow pattern are presented. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1978
- Accession Number
- ADA062093
Entities
People
- B. L. Hunt
- P. C. Dexter
Organizations
- University of Bristol