Shear velocity

Shear Velocity, also called friction velocity, is a form by which a shear stress may be re-written in units of velocity. It is useful as a method in fluid mechanics to compare true velocities, such as the velocity of a flow in a stream, to a velocity that relates shear between layers of flow. u ( z ) = u ∗ κ [ ln ⁡ ( z − d z 0 ) ] {displaystyle u(z)={frac {u_{*}}{kappa }}left} u ∗ = κ ( u ( z 2 ) − u ( z 1 ) ) ln ⁡ ( z 2 − d z 1 − d ) {displaystyle u_{*}={frac {kappa (u(z2)-u(z1))}{ln left({frac {z2-d}{z1-d}} ight)}}} Shear Velocity, also called friction velocity, is a form by which a shear stress may be re-written in units of velocity. It is useful as a method in fluid mechanics to compare true velocities, such as the velocity of a flow in a stream, to a velocity that relates shear between layers of flow.