Simulating the Vortex in a Spinning Rocket
Abstract
The continuing phenomena of coning in spin stabilized motor/ spacecraft is investigated using a laboratory-scale vortex generating model. This model simulated some of the forces associated with a vortex flow and allowed for altering the relationship between the vortex core flow and the nozzle. Altering the vortex core centerline produced differences in the measured side forces. The first configuration, with the vortex center aligned with the nozzle, produced no disturbing side forces. In subsequent tests, the misalignment of the vortex centerline with the nozzle centerline produced a side force that deflected the model from the vertical reference. The tangential velocity of the forced vortex produced the disturbing moment on the model. Conclusions include: (1) For every configuration tested, a misalignment of the center of the vortex and the center of the nozzle resulted in a steady force exerted on the nozzle at a right angle to a line connecting the center of the vortex and the center of the nozzle and in the direction directed by the tangential velocity; (2) The magnitude of the produced force can be accurately predicted from simple momentum consideration. Summation at the entrance of the nozzle indicates that the force derives from turning the tangential flow 90 deg to exit the nozzle; (3) The primary dependent variable seems to be the magnitude of the tangential velocity of the gas at the exit nozzle; and (4) Preliminary tests to simulate a submerged nozzle show the submerged nozzle does not appreciably change the side force magnitude or the direction. (5) Cursory tests done to simulate a contoured aft end indicate that the side force magnitude can be dramatically reduced -- but not eliminated -- by contouring the aft end.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1991
- Accession Number
- ADA236345
Entities
People
- Anjanette Knappenberger