# Law of the wall

(Difference between revisions)
 Revision as of 22:13, 16 May 2006 (view source)Jola (Talk | contribs)← Older edit Latest revision as of 08:32, 7 September 2011 (view source)Peter (Talk | contribs) m (Reverted edits by Peter (talk) to last revision by GeeZ) (9 intermediate revisions not shown) Line 1: Line 1: In the log layer the velocity profile can be estimated with the log law: In the log layer the velocity profile can be estimated with the log law: - :$u^+ = \frac{1}{\kappa} \, ln(y^+) + C$ + :$u^+ = \frac{1}{\kappa} \, ln(y^+) + B$ + + and close to the wall in the viscous sublayer + + :$u^+ = y^+$ Where: Where: Line 13: Line 17: |$\kappa$ || von Karman's constant ($\approx 0.41$) |$\kappa$ || von Karman's constant ($\approx 0.41$) |- |- - |$C$ || Constant ($\approx 5.1$) + |$B$ || Constant ($\approx 5.1$) |} |} ''We should have a lin-log plot here of a typical turbulent boundary layer to illustrate where the log-law is valid, anyone have one handy?'' ''We should have a lin-log plot here of a typical turbulent boundary layer to illustrate where the log-law is valid, anyone have one handy?'' + + In the image y is replaced with the letter n. + + [[Image:Img_lawOfTheWall_whiteBG.png‎]] {{stub}} {{stub}}

## Latest revision as of 08:32, 7 September 2011

In the log layer the velocity profile can be estimated with the log law:

$u^+ = \frac{1}{\kappa} \, ln(y^+) + B$

and close to the wall in the viscous sublayer

$u^+ = y^+$

Where:

 $u^+$ Dimensionless velocity $y^+$ Dimensionless wall distance $\kappa$ von Karman's constant ($\approx 0.41$) $B$ Constant ($\approx 5.1$)

We should have a lin-log plot here of a typical turbulent boundary layer to illustrate where the log-law is valid, anyone have one handy?

In the image y is replaced with the letter n.