Introduction to turbulence

From CFD-Wiki

Contents 1 What is turbulence? 2 The elements of statistical analysis 3 Reynolds averaged equations and the Turbulence Closure Problem 4 Turbulence kinetic energy 5 Stationarity and homogeneity 6 Homogeneous turbulence 7 Free turbulent shear flows 8 Wall bounded turbulent flows 9 Credits

What is turbulence?

• Why study turbulence?
• The cost of our ignorance
• What do we really know for sure?

The elements of statistical analysis

• Foreword

• The ensemble and Ensemble Average
  • The mean or ensemble average
  • Fluctuations about the mean
  • Higher moments
• Probability
  • The histogram and probability density function
  • The probability distribution
  • Gaussian (or normal) distributions
  • Skewness and kurtosis
• Multivariate random vaiables
  • Joint pdfs and joint moments
  • The bi-variate normal (or Gaussian) distribution
  • Statistical independence and lack of correlation
• Estimation from a Finite Number of Realizations
  • Estimators for averaged quantities
  • Bias and convergence of estimators
• Generalization to the estimator of any quantity

Reynolds averaged equations and the Turbulence Closure Problem

• The equations governing the instantaneous fluid motions
• Equations for the average velocity
• The turbulence problem
• The origins of turbulence

Turbulence kinetic energy

Stationarity and homogeneity

Homogeneous turbulence

Free turbulent shear flows

Wall bounded turbulent flows

Credits

This text was based on "Introduction to Turbulence" by Professor William K.George, Chalmers University of Technology, Sweden.

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