  We evaluate the effect of boundary layer losses on two-dimensional H2/O2/Ar
cellular detonations obtained in narrow channels. The experiments provide the
details of the cellular structure and the detonation speed deficits from the
ideal CJ speed. We model the effect of the boundary layer losses by
incorporating the flow divergence in the third dimension due to the negative
boundary layer displacement thickness, modeled using Mirels' theory. The
cellular structures obtained numerically with the resulting quasi-2D
formulation of the reactive Euler equations with two-step chain-branching
chemistry are found in excellent agreement with experiment, both in terms of
cell dynamics and velocity deficits, provided the boundary layer constant of
Mirels is modified by a factor of 2. A significant increase in the cell size is
found with increasing velocity deficit. This is found to be very well captured
by the induction zone increase in slower detonations due to the lower
temperatures in the induction zone.
