Large-Eddy/Reynolds-Averaged Navier-Stokes Simulation of Shock-Train Development in a Coil-Laser Diffuser

Abstract

This report describes the application of a hybrid large-eddy simulation / Reynolds-averaged Navier-Stokes method to predict shock train formation and reactant mixing in a model Chemical Oxygen Iodine Laser (COIL) unit. The configuration consists of a converging-diverging nozzle, a lasing cavity, and a diffuser. Results have been obtained for several grids and for several back pressures, the variation of which fixes the average shock-train position within the nozzle. Predictions of wall pressure are in reasonable accord with experimental observations for both LES/RANS and RANS model but tend to under-predict the initial rate of pressure increase as the flow encounters the leading edge of the shock train. Though the shock train induces a transition to turbulence as well as local flow separation, the effects of resolved turbulence and unsteady separation do not appear to influence the mixing process in the lasing cavity significantly.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Sep 06, 2014
Accession Number
ADA612441

Entities

People

  • Jack R. Edwards

Organizations

  • North Carolina State University

Tags

Communities of Interest

  • Energy and Power Technologies
  • Space

DTIC Thesaurus Topics

  • Air Force Research Laboratories
  • Back Pressure
  • Boundary Layer
  • Chemical Oxygen Iodine Lasers
  • Computational Fluid Dynamics
  • Diffusers
  • Flow
  • Large Eddy Simulation
  • Lasers
  • Mach Number
  • Payload
  • Pressure Distribution
  • Simulations
  • Supersonic Diffusers
  • Transitions
  • Turbulence
  • Turbulent Mixing

Fields of Study

  • Physics

Readers

  • Combustion and Flow Dynamics.
  • Fluid Mechanics and Fluid Dynamics.
  • Molecular Photonics/Laser Physics

Technology Areas

  • Directed Energy