Experimental data have been gathered on the local parameters of a boundary layer gas flow with ethanol combustion behind a 3 mm-high rib. These parameters include averaged velocities, temperatures, concentrations of stable substances and OH radicals and mass fluxes on the wall. The temperature and composition of the gases were studied with probe methods (thermocouple and chromatography). To measure the velocity and concentration of radicals, we applied the laser optical measurement methods of LDA and LIF. We propose a way of processing the obtained data utilizing balances in the continuity and motion equations. The influence of incident flow acceleration on the viscous and turbulent shear stresses at the wall and in the volume of the boundary layer has been analyzed to determine the acceleration parameters to be K = (0, 0.7, 13, and 4.1) x 10(-6). It is shown that without a longitudinal pressure gradient (K = 0) on the combustion that is behind the rib, OH radicals accumulate with their highest concentrations existing in areas that do not coincide with the flame front and are shifted toward the oxidizer. The main mechanism of momentum transfer is connected to the boundary layer separation. In the presence of acceleration caused by a negative longitudinal pressure gradient, the detachment area does not show up (in experiments with K > 0.7 x 10(-6)); shear stresses increase substantially and reach one percent of the dynamic pressure. The general level of turbulent stresses in the reacting boundary layer becomes higher than in the case without acceleration. The incident airflow is also accelerated by the reacting boundary layer in which the maximum velocity is formed. (C) 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.