46
P. Liu
Fig. 1.52 Turbulent velocity fluctuation and vortex structure
a change in physical quantities. If small eddies exist in large eddies, small fluctuations will occur in large fluctuations (as shown in Fig. 1.52). Because the
direction of velocity around these vortices is relative (opposite), large shear
stress will be produced.
(2) Irregularity of turbulence
The motion of fluid particles in turbulence is random and disorderly.
However, because turbulent flow contains vortices of different sizes, there is
no characteristic scale in theory, so this random walk must be accompanied
by transitions of various scales.
(3) Random Behavior of Turbulence
The physical quantities of particles in turbulent flow field are random variables of time and space, and their statistical average values obey certain regularity. In recent years, with the advent of fractal, chaotic science and the rapid
development of non-linear mechanics, people have a new understanding of
this randomness.
(4) Diffusion of turbulence
Due to the fluctuation and mixing of fluid particles, the diffusion of
momentum, energy, heat, mass, and concentration in turbulence is greatly
increased, which is obviously larger than that in laminar flow.
P. Liu
Fig. 1.52 Turbulent velocity fluctuation and vortex structure
a change in physical quantities. If small eddies exist in large eddies, small fluctuations will occur in large fluctuations (as shown in Fig. 1.52). Because the
direction of velocity around these vortices is relative (opposite), large shear
stress will be produced.
(2) Irregularity of turbulence
The motion of fluid particles in turbulence is random and disorderly.
However, because turbulent flow contains vortices of different sizes, there is
no characteristic scale in theory, so this random walk must be accompanied
by transitions of various scales.
(3) Random Behavior of Turbulence
The physical quantities of particles in turbulent flow field are random variables of time and space, and their statistical average values obey certain regularity. In recent years, with the advent of fractal, chaotic science and the rapid
development of non-linear mechanics, people have a new understanding of
this randomness.
(4) Diffusion of turbulence
Due to the fluctuation and mixing of fluid particles, the diffusion of
momentum, energy, heat, mass, and concentration in turbulence is greatly
increased, which is obviously larger than that in laminar flow.