Computations of Chaotic Flows in Micromixers

Abstract

Three-dimensional simulations of the incompressible Navier-Stokes equations are used to examine the effects of repeating sequences of herringbone ridges in a microchannel. The calculations show how the presence of the structures leads to an asymmetrical pattern of transverse vortices in the velocity field, how this pattern repeats as the fluid moves over each similar sequence of ridges, how this velocity field stretches and folds fluid elements, and how this can lead to chaotic advection. A series of calculations with increasing numerical resolution show the varying rates of convergence of the flow velocity and passive-scalar convection and mixing as the fluid traverses more sequences. Mixing and convection are studied through traces of marker particles and through fluid convection of passive scalars, and these are compared. Numerical tests show the adequacy of structured grids and a numerical algorithm for multidimensional incompressible flow. A methodology is developed and described that is used to assess accuracy and reduce the cost of such computations.

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Document Details

Document Type
Technical Report
Publication Date
Apr 07, 2006
Accession Number
ADA446806

Entities

People

  • Carolyn R. Kaplan
  • David R. Mott
  • Elaine Oran
  • Junhui Liu

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Boundary Layer
  • Computational Fluid Dynamics
  • Convection
  • Fluid Dynamics
  • Fluid Flow
  • Fluid Mechanics
  • Incompressible Flow
  • Mechanical Properties
  • Navier Stokes Equations
  • Physics Laboratories
  • Pipe Flow
  • Pressure Gradients
  • Steady State
  • Stratified Fluids
  • Three Dimensional
  • Turbulent Mixing
  • Viscous Flow

Readers

  • Computational Fluid Dynamics (CFD)
  • Fluid Mechanics and Fluid Dynamics.