Regeneration and Self-Maintaining of Coherent Structures - Transport and Coherent Structures in Wall Turbulence - page 308

) (

)

(

see that the contribution of is five

− ∂∂ ∂ wx Uu y + ∂

( ) ( )( )

times greater than is

an entire order of magnitude lesser than the tilting
[BRO 93]. The regeneration begins in the lower buffer
sublayer

, and that

ω∂ ∂ ux ∂∂ ∂∂ vx uz

x

in which production by tilting of the wall-
normal vorticity is dominant.

y + ≤ 10

Figure 5.15. Regeneration of structures according to [BRO 93].
This figure is adapted from [TAR 95a]

[BRO 93] analyze conditional aver ag es to reveal the
structures associated with

) (

)

(

, at a

− ∂∂ ∂ wx Uu y + ∂ > 0.03

reference position . The data at a

given time are stored when the corresponding criterion is
fulfilled, and are averaged later on. Figure 5.17 shows the

+ +

==

and y + = 6.5

xz 0