Instabilities and Turbulence in Intermediate Altitude Fireballs
Abstract
Higher order and finely zoned calculations with the SHARC code have indicated that the tops of intermediate attitude fireballs are unstable. This report describes the characteristics of the instabilities and their evolution. To aid in the understanding and interpretation of the computed fireball instabilities, a number of idealized numerical experiments of the Rayleigh- Taylor and Richtmyer-Meshkow instabilities were completed. A strong zoning dependent numerical viscosity was noted. Results from the numerical experiments and their implications to fireball calculations are presented. The current SHARC turbulence model, when applied to fireballs, generates few identifiable effects. However, evidence is provided that the model, as currently implemented, provides an inadequate treatment for flows in which the dominant turbulence generation mechanism is due to the interaction of the density and pressure fields. Steps are underway to provide a more general formulation of the model. Intermediate Altitude SHARC Code Turbulence Modeling Nuclear Effects Hydrodynamics K-e Turbulence Model Instabilities Fireball.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1992
- Accession Number
- ADA248505
Entities
People
- Charles E. Needham
- Theodore C. Carney