Introduction. Paper considers methods for analyzing the impact of wind flow on chimney-type frame-and-sheath 12-sided steel cooling tower (SCT) with irrigation area of 1600 m². The main goal of conducting numerical and experimental studies of wind flow around the SCT is to verify the experimental data obtained in wind tunnel, as well as to select turbulence model that most accurately describes the phenomena obtained during experimental studies. The development of chimney-type frame-and-sheath steel cooling towers faces number of unsolved problems, which significantly complicates the design process. The main obstacle is lack of clearly substantiated values of loads and impacts on such structures in current regulatory documents. Wind action, being inconstant in strength and direction, has a significant impact on the bearing capacity of cooling tower, taking into account its shape. These studies will not only clarify the calculated values of wind pressure, but also develop more effective methods for calculating loads on cooling towers.

Materials and methods. The work is based on use of such approaches of construction aerodynamics as tensometric weight studies, method of drainage of models, methods of wind flow visualization "velocimetry", or shadow method, method of silk threads, allowing to fully evaluate the behavior of the structure in wind flow. Using AutoCAD CFD software was performed numerical analysis with subsequent comparison of data obtained results with experimental studies. During experimental part of study were used models made by means of 3D printing for blowing in construction wind tunnel, taking into account the frame of steel casing of cooling tower to determine the actual diagrams of wind pressure distribution on tower frame-casing cooling tower with hyperbolic shape, taking into account the seasonality of operation, as well as stages of construction, to identify the most unfavorable design situations of the wind influence.

Results. The values of the total wind pressure coefficients Cx, Cy, C_Mz have been determined, confirming the high comparability of the experimental data within the range from 95 % to 100 % with national standards. The values and nature of the distribution of local aerodynamic coefficients Cp differ from those proposed in regulatory documents in terms of peak values at an active pressure of 30 % to 50 %, the length of the region and zones with negative pressures that occur when a vortex comes off. The independence of the aerodynamic coefficient Cp from the Reynolds number R_e within the range from 2,71 × 105 to 3,29 × 105. Theory Reynolds Averaged Navier-Stokes SST k-ω DES analysis has been substantiated, most accurately describing the nature of wind flow around design models.

Conclusions. The data of experimental studies allowed to establish the values of the coefficients of total wind pressure, similarity criteria, as well as the values and nature of the distribution of local aerodynamic coefficients on the design of the cooling tower. Based on the results of numerical and experimental studies is proposed refined method for standardizing the wind effect on frame-and-sheath 12-sided steel cooling tower with irrigation area of 1600 m² taking into account the seasonality of operation and construction stages.