# Dimensionless velocity

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
$u^+ \equiv \frac{U}{u_*}$
Where $U$ is the local velocity and $u_*$ is the friction velocity at the closest wall.
$u^+$ is called the dimensionless velocity and is commonly used in boundary layer theory and in defining the law of the wall.