Most deepwater tubulars experiencing high currents frequently require vortex-induced vibration (VIV) suppression to maintain an acceptable fatigue life. Helical strakes and fairings are the most popular types of VIV suppression devices in use today.
It is quite common to use only one type of device (helical strakes or fairings) on a single tubular and, in fact, to use a single device type on an entire tubular array. The use of both styles of suppression devices on a single tubular has grown in popularity, but mixing them within an array is a relatively new concept. It is sometimes desirable to use one suppression device on one tubular and another suppression device on an adjacent or tandem tubular.
This paper utilizes results from two different types of VIV experiments. The first consists of a long tubular at high Reynolds numbers with VIV suppression on the outer end where current speeds are the highest. The use of only fairings, only strakes, or a mixture of the two devices is examined.
The second VIV experiment examines the use of helical strakes on one tubular and fairings on a tandem tubular. Results are compared to experiments with either helical strakes on both tubulars or fairings on both tubulars. This paper is intended to provide some direction, and in many cases assurance, for mixing helical strakes and fairings on deepwater tubulars.