This is an adjunct to Project No. 2, Dynamic Response of Offshore Structures. Strumming experiments were conducted on long pipes in a tidal estuary where currents range to 1.5 knots. These experiments will simulate the strumming characteristics of production risers which may be used in deepwater operations. Future plans include possible testing of riser behavior in deep water where they can be vertically oriented.
Complete. A peculiar experimental observation deduced from the Castine data is that the in-line response frequencies do not always correspond to the structures natural frequencies. Instead, they are equal to double or sum of some of the cross-flow response frequencies for both lock-in and non lock-in cases. Additional studies were conducted on these observations.