Turbulence and Dispersion over Complex Terrain

Abstract

Large-Eddy Simulation (LES) is used to generate explicit time-dependent, three-dimensional representations of the turbulent flow field over sinusoidal hills. An advanced Lagrangian puff model is used to calculate dispersion from a small source near the surface within the turbulent flow. The puff model represents the local shear distortions, and includes a splitting algorithm to give an accurate description of the inhomogeneous velocity field In order to provide a measure of confidence in the LES flow simulations, an extensive comparison with laboratory measurements of turbulent flow over wavy surfaces has been completed. Model predictions compare very favorably with the experimental data. Dispersion calculations using the LES velocity fields show strong effects of the terrain on releases from point sources near the surface. In separated flow conditions, wide variability in cloud behavior is observed due to the retention of material within the recirculating valley flow.

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Document Details

Document Type
Technical Report
Publication Date
Jun 01, 2000
Accession Number
ADA384744

Entities

People

  • D. S. Henn
  • R. I. Sykes

Organizations

  • Titan Corp.

Tags

DTIC Thesaurus Topics

  • Boundary Layer
  • Boundary Layer Flow
  • Central Processing Units
  • Computational Fluid Dynamics
  • Coordinate Systems
  • Equations Of Motion
  • Experimental Data
  • Fluid Dynamics
  • Fluid Mechanics
  • Measurement
  • Mechanics
  • Secondary Flow
  • Simulations
  • Stratified Fluids
  • Turbulence
  • Turbulent Flow
  • Turbulent Mixing

Fields of Study

  • Physics

Readers

  • Aerosol Science/Aerosol Physics
  • Computational Fluid Dynamics (CFD)
  • Fluid Mechanics and Fluid Dynamics.