ABSTRACT: Evaluation of validity is realized by comparing results of computer model to data measured on physical full-scale model. Two characteristic parameters are evaluated, ratio of stagnation pressure in the outer stream of the outlet and in the inlet of outer stream. Used CFD system is Ansys CFX. System Ansys CFX is applied with turbulence model of k-epsilon SST with structured numerical grid with detailed resolution in the volume of boundary layer. Computational results confirm capability of current CFD systems to accurately predict parameters of air channel, without accounting for design details and as well to accurately predict the effect of losses on power parameters, provided the numerical grid which is used properly for solving details of the boundary layer. This work is very useful for practical communication in industry, because it specifies conditions for reliable application of CFD methods in computation of air channel around the historical building.