Computational Fluid Dynamics Laboratory

Turbulent Inlet Conditions

A study has been performed which investigates the effect of stochastic inlet conditions on the development of a fully-turbulent jet. The jet under consideration has a Reynolds number of 21,000, to match the experimental jet of Amielh et al. (1996). Both Gaussian random fluctuations and a Spectral Representation of turbulence were tested as stochastic representations of inlet turbulence. It was found that Gaussian random fluctuations dissipate almost immediately, while the spectral fluctuations yield sustaining structures that develop rapidly into real turbulence. Please see the following reference for details of this work.
Glaze, David J. and Frankel, Steven H., "Stochastic Inlet Conditions for Large-Eddy Simulation of a Fully Turbulent Jet," AIAA Journal, 41(6):1064-1073, 2003.
Below is an animation of mixture fraction in a slice through the centerline of a jet using the Spectral Representation inlet conditions.

Mixture Fraction
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Below is an animation of an isosurface of mixture fraction (Z=0.05) in a turbulent jet, colored by the mixture fraction dissipation rate. The bottom and back walls show mixture fraction and dissipation rate, respectively, in slices through the jet centerline.

Mixture Fraction Colored
by Dissipation Rate
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Below is an animation of turbulent structures in a turbulent jet, along with a slice of mixture fraction and velocity vectors through the jet centerline.

Vortical Turbulent Structures
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