A mean wind force acts on a building. This means wind force is derived from the mean wind speed and the fluctuating wind force produced by the fluctuating flow field. The effect of the fluctuating wind force on the building or part thereof depends not only on the characteristics of the fluctuating wind force but also on the size and vibration characteristics of the building or part thereof.
Therefore, in order to estimate the design wind load, it is necessary to evaluate the characteristics of fluctuating wind forces and the dynamic characteristics of the building. The following factors are generally considered in determining the fluctuating wind force.
1- wind turbulence (temporal and spatial fluctuation of wind)
2- vortex generation in the wake of building
3- the interaction between building vibration and surrounding airflow