Abstract <p>This paper deals with justification of the applicability of a model for a coupled prediction of flows in a porous body–free stream system. The considered model is based on the generalized Navier‒Stokes equations for an incompressible fluid obtained by averaging over a representative elementary volume of the porous medium and written for the entire computational domain, including both the porous medium and the pure fluid. Numerical implementation of the model is performed using the open computational platform FEniCS. To validate the model, we used the experimental data containing measured flow velocity profiles in a channel of a rectangular cross section partially filled with a porous body. The model porous body is a square array of parallel circular rods arranged vertically on a section of the channel bottom. The validation calculations of the flow corresponding to the Darcy filtration regime demonstrate close agreement of the numerical results with the values of local measurements in a wide range of porosity values.</p>