Properties of Turbulent Flow

• Turbulent fluid flows are characterized by chaotic fluid motions. A high degree of mixing exists and a high diffusivity is observed.

Figure 1.2

• The diffusion processes that are caused by molecular motions are usually small in comparison to those caused by turbulent fluid motions.

Figure 1.3

• The velocity gradient results in a amplification of disturbances as explained above.
  
  
  
• Damping and amplification can appear in a super imposed way.

Figure 1.4

Turbulent flows contain vorticity. Vortices of different length scales occur in the flow.

L = integral length scale             λ = micro scale of turbulence

Turbulent flows are mostly explained by L and λ .