Serving as one key component of the most important lifeline infrastructure system, transmission towers are vulnerable to multiple nature hazards including strong wind and could pose severe threats to the power system security with possible blackouts under extreme weather conditions, such as hurricanes, derechoes, or winter storms. For the security and resiliency of the power system, it is impor...

This paper investigates the relationships between friction velocity, 10m drag coefficient, and 10m wind speed using data collected at two offshore observation towers (one over the sea and the other on an island) from seven typhoon episodes in the South China Sea from 2008 to 2014. The two towers were placed in areas with different water depths along a shore-normal line. The depth of water at th...

We investigate the strong stabilization of a wind turbine tower model in the plane of the turbine blades, which comprises a nonuniform SCOLE system and a two-mass drive-train model (with gearbox). The control input is the torque created by the electrical generator. Using a strong stabilization theorem for a class of impedance passive linear systems with bounded control and observation operators...

Wind tunnel experiments were performed to examine the effect of a tall tower on the flow around an otherwise uniform array of buildings. Additionally, preliminary CFD simulations were run to visualize the flow with more resolution. The model used in both the wind tunnel and CFD studies was designed to simulate an area of Brooklyn, NY, USA, where blocks of residential row houses form a neighborh...

Negative aerodynamic damping causes tower vibrations on turbines with stall rotors. Under certain conditions, these vibrations may rise to a level that causes a shutdown. Active stall turbines have a pitch system, and the objective of the work was to develop pitch control algorithms which would minimise the probability of tower vibrations rising to the shutdown level. The results of a root caus...

Wind catchers (wind towers) are one component of the traditional sustainable buildings with a centralcourtyard in the hot regions of Iran. In this research a most common type of the wind tower – the foursided wind catcherwas evaluated both experimentally and numerically. The tower of the Mortazhouse in the city center of Yazd was equipped with temperature, wind, air velocity and...

A wind turbine is a device that exploits the wind’s kinetic energy by converting it into useful mechanical energy. It basically consists of rotating aerodynamical surfaces (blades) mounted on a hub/shaft assembly, which transmits the produced mechanical power to the selected energy utilizer (e.g. milling or grinding machine, pump, or generator). A control system is usually provided for adjustin...

Operating horizontal axis wind turbines (HAWT) generate large-scale wake structures that can have considerable impact on downwind turbines. A HAWT exposed to vortices from upwind turbines generally produces reduced power and experiences increased structural vibrations that cause disproportionally accelerated material fatigue. Numerical simulation of the turbulent flow field is a viable approach...

This paper builds on previous research by the authors which determined the global state-of-the-art of constructing tall buildings by surveying the most active specialist tall building professionals around the globe. That research identified the effect of wind on tower cranes as a highly ranked, common critical issue in tall building construction. The research reported here presents a design for...