Numerical prediction of deflection of a cylindrical hollow structure due to steady wind loads

Abstract

A raising population and to meet the raising needs there is an increasing demand for tall structure both for commercial use and industrial purpose. Wind behaviour is a key design parameter for such structures and need to be assessed accurately in the preliminary and secondary design stages. This study is aimed at prediction and analysis of deflection of hollow structure due to steady wind loads. Hollow structures typically represent chimneys that are used in the coal fired stream power plant. A hollow cylindrical part with base diameter of 6 cm is fabricated and tested in wind tunnel at constant speeds of 10, 15 and 20 m/s. An accelerometer is mounted on top of body to measure the deflection. Next, the deflection of the body is predicted numerically using commercial ANSYS software. Initially Computational Fluid Dynamics (CFD) simulations are performed to predict the flow field and associated wind force acting on the body. The wind load is transferred to the structural solver to predict the deflection of the body. The predicted deflection compared well with the wind tunnel experiments. Further FSI simulations are performed by changing the thickness of the hollow structure. The results are analysed to study the effect of wind speed and thickness on the deflection. A cubic polynomial curve-fit for the deflection, as a function of the wind speed is developed.