HELICAL STRAKES

While fairings consist of a structure having two sides that streamline the flow past the structure (such as an airplane wing), helical strakes consist of one or more fins that spiral along the structure's length. If the fins are effectively sized and designed, then th e fins cause the vortices to break up into short lengths. This causes the vortices along the structure's length to be broken up into shorter and weaker segments. Further, the breaking up of the vortices reduces their ability to correlate along the span, resulting a series of vortices that are randomly phased in time. The net result is that, while the structure still experiences strong local forces, the randomness of the forcing frequency along the structure's length produces only a small net vibration of the structure.