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
E c = u 2 c p Δ T = Advective Transport Heat Dissipation Potential {\displaystyle \mathrm {Ec} ={\frac {u^{2}}{c_{p}\Delta T}}={\frac {\mbox{Advective Transport}}{\mbox{Heat Dissipation Potential}}}}
where
u is the local flow velocity of the continuum, cp is the constant-pressure local specific heat of the continuum,
Δ T {\displaystyle \Delta T} is the difference between wall temperature and local temperature.
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