  3D hydrodynamics models of deep stellar convection exhibit turbulent
entrainment at the convective-radiative boundary which follows the entrainment
law, varying with boundary penetrability. We implement the entrainment law in
the 1D Geneva stellar evolution code. We then calculate models between 1.5 and
60 M$_{\odot}$ at solar metallicity ($Z=0.014$) and compare them to previous
generations of models and observations on the main sequence. The boundary
penetrability, quantified by the bulk Richardson number, $Ri_{\mathrm{B}}$,
varies with mass and to a smaller extent with time. The variation of
$Ri_{\mathrm{B}}$ with mass is due to the mass dependence of typical convective
velocities in the core and hence the luminosity of the star. The chemical
gradient above the convective core dominates the variation of $Ri_{\mathrm{B}}$
with time. An entrainment law method can therefore explain the apparent mass
dependence of convective boundary mixing through $Ri_{\mathrm{B}}$. New models
including entrainment can better reproduce the mass dependence of the main
sequence width using entrainment law parameters $A \sim 2 \times 10^{-4}$ and
$n=1$. We compare these empirically constrained values to the results of 3D
hydrodynamics simulations and discuss implications.
