A New Paradigm for Turbulence Control for Drag Reduction

Abstract

Direct numerical simulations (DNS) of span wise-rotating turbulent channel flow as well as the neutral and unstable turbulent Ekman layer were conducted. These DNS results were used to evaluate various turbulence and heat transfer models for the Reynolds stresses, turbulent heat fluxes and higher-order moments of velocity and temperature. Explicit Algebraic Reynolds Stress Models (EARSM) obtained the Reynolds stress distributions in best agreement with DNS data for rotational flows and turbulent heat flux distributions obtained from two explicit algebraic heat flux models consistently displayed increasing disagreement with DNS data with increasing rotation rate. DNS results were also used to determine the proper computational box size for a minimal flow unit (MFU) at Ro_b=0.5. For the neutrally stratified Ekman layer, the higher-order moments of velocity were examined and the accuracy of a kurtosis model was assessed. For the unstable Ekman layer, the analysis of higher-order moments was extended to temperature-velocity correlations.

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Document Details

Document Type
Technical Report
Publication Date
Feb 27, 2017
Accession Number
AD1030879

Entities

People

  • Mahmoud Hussein

Organizations

  • Regents of the University of Colorado

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Amplitude
  • Boundary Layer
  • Channel Flow
  • Computational Fluid Dynamics
  • Computational Science
  • Drag
  • Drag Reduction
  • Energy
  • Energy Transfer
  • Flow
  • Fluid Dynamics
  • Fluid Flow
  • Heat Flux
  • Heat Transfer
  • Hypervelocity Flow
  • Kinetic Energy
  • Reynolds Number

Readers

  • Fluid Dynamics.
  • Ocean-Atmosphere Mesoscale Modeling, Data Assimilation, and Flux Boundary Layers