Measurement of Surface Pressures Caused by a Projectile Rotating Band at Supersonic Speeds.
ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
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The objective of this report is to describe the results from a series of supersonic wind tunnel tests designed to measure the pressure distribution in front of, as well as behind a ring protuberance of the order of the boundary layer thickness on an axisymmetric body. In principle, the construction of such a model is straight forward. However, there are practical limitations on the resolution of the pressure distribution which can be obtained particularly with small models. In order to increase the detail observed, an attempt has been made here to measure the pressure distribution using a few fixed pressure orifices located in front of and behind a movable band. The bands range of positions are all located in a nearly constant pressure region on the basic model. Therefore, it can be assumed that the boundary layer thickness varies only slightly over the region of the band positions. It was expected that the pressures induced by the protuberance would be effected only in a secondary way by the changing position of the band. Thus it is also an objective of this work to assess the validity of this assuption. The flow over a protuberance is a fundamental and difficult problem in fluid mechanics. It involves the strong interaction of separated flow regions ahead of and behind the obstacle, as well as the viscous and inviscid flow fields. The most frequently occurring situation involves separation of a turbulent boundary layer. Therefore, data on this type of flow provides a valuable test case for turbulent flow prediction techniques. Author
- Test Facilities, Equipment and Methods
- Ammunition and Explosives
- Fluid Mechanics