Premixed Flames

  • What are the names of the large and small scales of motion in turbulence?
  • Derive the small length scale of turbulence in terms of kinematic viscosity and kinetic energy dissipation rate.
  • Derive the small time scale of turbulence in terms of kinematic viscosity and kinetic energy dissipation rate.
  • What is the Reynolds number based on the small scales?
  • What is the ratio of the large-to-small length scales based on the large-scale Reynolds number?
  • What does a term like $\overline{u^\prime v^\prime}$ represent physically?
    • What are it’s units when multiplied by density?
    • How does this compare to the units of the viscous stress $\tau$?
  • For a given jet exit diameter, how does the length of a turbulent jet change when the exit velocity/flow rate changes?
  • What is a Reynolds decomposition?
  • What is a Favre decomposition and why is it used in combustion applications?