Dynamic Response of Offshore Articulated Tower-Under Correlated Wind and Wave

Articulated tower is a compliant offshore structure that oscillates freely with environmental loads of wind and wave. Present study deals with the dynamic response of a single hinge Articulated tower. Hydrodynamic loading of the tower is computed using Morrisons equation. Acceleration and velocity terms used in Morrison equation is computed first by Airy theory and then by Stokes theory. Various responses of the Articulated tower are studied and a comparative analysis is done so as to see which of Airy wave and Stokes wave gives better response. Response of this Articulated tower is then studied under wave alone environment and wind+wave correlated environment. Fluctuating component of the wind is modelled by Simiu’s spectrum, while the sea state is characterized by Pierson-Mosokowitz (P-M) spectrum. Random waves and wind are simulated by Monte Carlo simulation technique. Response of Articulated tower is determined by time domain iterative method using Newmarks’s -β integration scheme. It is concluded that Stokes wave gives improved response and presence odd wind forces along with the waves amplify the responses significantly particularly at lower frequencies.