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Law of the wall

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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:
-
:<math>u^+ = \frac{1}{\kappa} \, ln(y^+) + C</math>
+
:<math>u^+ = \frac{1}{\kappa} \, ln(y^+) + B</math>
 +
 
 +
and close to the wall in the viscous sublayer
 +
 
 +
:<math>u^+ = y^+</math>
Where:
Where:
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|<math>\kappa</math> || von Karman's constant (<math>\approx 0.41</math>)
|<math>\kappa</math> || von Karman's constant (<math>\approx 0.41</math>)
|-
|-
-
|<math>C</math> || Constant (<math>\approx 5.0</math>)
+
|<math>B</math> || Constant (<math>\approx 5.1</math>)
|}
|}
''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]]
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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.

Img lawOfTheWall whiteBG.png


My wiki