The frequency of the vortices is dependent on the shape of the blunt body, and the velocity of the fluid flow or wind hitting this body. The vortices create low pressure zones on the downwind side of the object on alternate sides. As the fluid flows to fill the low pressure zone, it produces a vibration at a specific calculable frequency. This vibration is only a major concern if it happens to coincide with the natural frequency of the structure. For structures that are tall and uniform in size and shape, the vibrations can be damaging and ultimately lead to fatigue failure. Masts or towers are highly susceptible to vibrations induced by vortex shedding. By completing a vortex shedding analysis of structures under realistic wind loading, engineers can evaluate whether more efficient structures can and should be developed.