<p>The article describes the main methods for determining the hydrodynamic characteristics of a water flow interacting with a pipeline crossing. Mathematical modeling of free-stream flow around a pipeline junction was performed using the ANSYS^® Fluent software package. The mathematical model was verified based on a comparison of the results of numerical modeling with the experimental results obtained in a wind tunnel for flow around a pipeline lying on the screen. The degree of influence of the method of attaching the pipeline transition model to the screen during physical modeling in a wind tunnel was determined.</p>