Aerodynamic Damping of Helical Shaped Super Tall Building

Abstract

Aerodynamic instability and aerodynamic damping ratio of 180° helical model which shows better aerodynamic behavior in both along-wind and crosswind responses on a super tall building was investigated through wind tunnel tests using rocking model, and the aerodynamic damping ratio was evaluated from the wind-induced responses of the model by using Random Decrement Technique (RDT). The aerodynamic damping ratios in along-wind and across-wind direction were verified through comparison with previous research results and that derived by quasi-steady theory. As a result, the aerodynamic instability of the 180&#61616 helical model in across-wind direction were not occurred for any conditions with increasing the reduced wind velocity while the square model generally encounters aerodynamic instability due to the vortex shedding (Lock-in Phenomenon).g model, and the aerodynamic damping ratio was evaluated from the wind-induced responses of the model by using Random Decrement Technique (RDT). The aerodynamic damping ratios in along-wind and across-wind direction were verified through comparison with previous research results and that derived by quasi-steady theory. As a result, the aerodynamic instability of the 180&#61616 helical model in across-wind direction were not occurred for any conditions with increasing the reduced wind velocity while the square model generally encounters aerodynamic instability due to the vortex shedding (Lock-in Phenomenon).