Determination of wind force acting on an object in the shape of a bent pipe

The aim of the paper is to determine the aerodynamic forces acting on a torus-shaped structure fragment at high wind velocity which are impossible to obtain from the existing standard EN 1991-1-4 (the so-called wind standard). The most important problem is the correct modeling of turbulence and laminar-turbulent transition in the conditions of flow interference resulting from the presence of other obstacles. For this reason, forces are obtained by two methods: fluid-structure interaction (FSI, force transfer) and user-defined functions (UDF). Variations of the total aerodynamic lift force of the half of the torus with angle β and velocity of wind w, and the formula for estimating the horizontal force P_z perpendicular to drag force are presented. Additionally, useful engineering parameters (such as pressure distribution and air velocity field) are determined. The forces of wind influence on two cylinders and a torus-shaped object are obtained and compared.