© 2022, Pleiades Publishing, Ltd.Abstract: The separation zones resulting from the wind interaction with a building and its immediate surroundings are of great importance for determination of multiple vortex systems interacting with the building and for consideration of appropriate design parameters. In this study, flow structures around building models having dimensions of 5 × 5 × 5 cm (Model B), 5 × 5 × 10 cm (Model C), and 5 × 10 × 5 cm (Model D) with a 30° slope and rooftop were examined experimentally with a distance of 13.75 cm between two models (Model B and C; Model C and D) with the use of Particle Image Velocimetry (PIV). Besides, the experimental work of placing binary building was numerically researched with the use of ANSYS Fluent 16.0 software program with the (Formula presented.) turbulence model for a three-dimensional steady state, and the obtained numerical results were compared with the experimental results. Instantaneous velocity fields were firstly obtained in the experiments, and then the streamlines (Formula presented.), velocity distributions < V >, and vortex peer curves (Formula presented.) were plotted based on these data. The average equivalent velocity curve distributions in the x and y directions were also investigated for both pairs of building models. The results showed that the vortex lengths on the back of Model C increased by 13.33% as compared with Model B. The obtained result demonstrated that the geometric features had an effect on the formation of vortex separation zones. Comparison of the experimental and numerical results gave a deviation of maximum 3%.