..., the 2nd order diffraction quantities such as drift force and QTF are also affected by motion RAOs. In this paper the drift force coefficients and QTF calculation are based on the RAO where a Morison drag formula is included, and two cases are studied to investigate the effects of viscous loading...

... jonkman excitation second-order wave load upstream oil & gas simulation pitch eigenfrequency stiffness subsea system rigid tlp frequency qtf wind energy first-order wave load flexibility flexible tower eigenfrequency cutoff frequency wave load robertson renewable energy...

... Abstract This paper describes and validates a method for estimating quadratic transfer functions (QTF) for floating structures based on model experiments with irregular wave loading. With the QTF for a specific floating moored structure the slow drift forces acting on the structure can...

...) for simulation of extreme vertical motions of offshore structures in the very high seas. The UNIOM-diffraction (LTF and QTF) has been applied to lateral wave-exciting force due to high seas. For instance, simulation has been done for horizontal force on the fixed large diameter column in the phenomenal seas...

... ABSTRACT The objective of the paper is an analysis of the model test data of a mini-TLP, which includes the quality and degree of non-Gaussianity of the measured data; comparison of Gaussian and Non-Gaussian method for the estimation of QTFs. The comparison between the two methods is made...

... and compared with the experiment, both in the time and frequency domain. The LTF and linear coherency function are affected by the sea severity and data length. The non-Gaussian method for estimation of QTF is more affected by data length than Gaussian input method. INDRODUCTION Many a study on the response...

... measured the surge wave exciting forces. Using these waves and forces, we have estimated the cross and cross-bi-spectra, from which we determined experimental linear and quadratic transfer functions (LTF and QTF). Making use of the above we have reconstructed the wave forces and compared with measured wave...

... ABSTRACT Due to the lack of experimental data, we have simulated 2"d-order random waves and surging forces on a fixed barge to be used as input and output. These data were used for the cross spectral and cross-bispectral estimates, from which the system characteristics LTF and QTF were...

.... qtf offshore natural frequency simulation nonlinear response ringing tension time series spectrum wave force time domain simulation frequency artificial intelligence polar eng platform time series heidrun tlp uniom high frequency tension Time Domain Simulation of Ringing...

... to the numerical modeling. second-order diffraction wacyl transfer function platform qtf prediction skewness fine mesh wamit winterstein matrix multicolumn airgap response kurtosis calculation hydrodynamic analysis diagonal mesh Proceedings ofthe Eleventh (2001) International Offshore...

... against the measured loads on the fixed cylinder due to the MAR1NTEK ringing waves (Stansberg et al., 1995). The ULSM was applied in this paper to simulate the wave loads on ISSC TLP due to the above MARINTEK ringing wave. qtf ringing ulsm time series wave force marintek frequency resonance...

... krokstad frequency subsea system extreme value equation spectrum naess modeling & simulation qtf Proceedings of the Fourth (1994) InteTlUltional Offshore and Polar Engineering Conference Osaluz, Japan, April 10-15, 1994 Copynght © 1994 by The InternatIOnal SOCUIty of Offshore and Powr...

... is sometimes denoted as ringing, appears more or less as an Impulse response, i e a transient motion occurring at the platforms" eigenfrequencies in heave, roll and pitch. netherlands qtf estimate frequency model test wave component qtf artificial intelligence proceedmg spectrum transfer...

... sea state frequency sum-frequency force sum-frequency excitation variation procedure sum-frequency effect implementation qtf extreme response separation frequency case study platform transfer function tether response qtf data fatigue damage upstream oil & gas calculation...