The Eckert number (Ec) is a dimensionless number used in continuum mechanics. It expresses the relationship between a flow's kinetic energy and the boundary layer enthalpy difference, and is used to characterize heat transfer dissipation. It is named after Ernst R. G. Eckert.
It is defined as
:<math>
\mathrm{Ec} = \frac{u^2}{c_p \Delta T} = \frac{ \mbox{Advective Transport} }{ \mbox{Heat Dissipation Potential
</math>
where
- u is the local flow velocity of the continuum,
- c<sub>p</sub> is the constant-pressure local specific heat of the continuum,
- <math>\Delta T</math> is the difference between wall temperature and local temperature.