Date of Award

3-2005

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Aeronautics and Astronautics

First Advisor

Raymond C. Maple, PhD

Abstract

Validation of the turbulence models in the CFD code Beggar for unsteady turbulent flow are discussed. Six validation cases of the code are considered, three cases with the intent of validating the code without the turbulence model and three cases to validate the turbulence model itself. Finally, a more realistic simulation of a simplified store is examined. The turbulence models considered are the Baldwin-Lomax, Spalart-Allmaras, and a DES model. The conclusions made deal with necessary prerequisites to properly simulating unsteady turbulent flow and model selection. The prerequisites necessary in the Beggar code are a second order temporal discretization and the calculation of at least three Newton dt-iterations per time step. Baldwin-Lomax overpredicts unsteady effects. The Spalart-Allmaras model was found to not properly simulate unsteady turbulent flow and is possible written incorrectly in Beggar. A recommendation of whether to use the DES model or not cannot be made due to time and computational constraints and temporary problems within the Beggar code.

AFIT Designator

AFIT-GAE-ENY-05-M22

DTIC Accession Number

ADA437548

Download

Share

COinS