Aerodynamic Side Force Induced by Nozzle Entrance Flow Asymmetry
Abstract
The Star 48 upper stage rocket motor and payload system appears to precess in a coning motion which affects the flight path. The coning motion has been attributed to side forces generated because of deviations of the rocket nozzle entrance flow from truly axisymmetric conditions. In this report, an experimental investigation is described in which intentional nozzle entrance flow misalignment was produced and consequent side force was measured on a model at a simulated altitude of 170,000 ft. Side forces generated with an approximately 1/50th scale Star 48 rocket nozzle were quite small when compared to the predictions and measurements of previous investigators, but the difference was attributed to the difference where the flow inclination or misalignment occurs. When the flow is inclined at the nozzle throat, the downstream effect of the inclination is predictably large. When the flow is inclined in the plenum upstream of the nozzle entrance, the downstream effect is smaller by an order of magnitude. The observed side forces show a dependence on the nozzle length, as indicated by earlier investigators. Keywords: Rocket nozzles; Nozzle gas flow; Liquid propellant rockets; Rocket nozzles.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1988
- Accession Number
- ADA206631
Entities
People
- Donald A. Durran
- Edward K. Ruth
- James S. Whittier
- Robert L. Varwig
- Rudolf X. Meyer
Organizations
- The Aerospace Corporation