QTF data are typically obtained as part of a larger set of vessel type data from a diffraction analysis, performed in the frequency domain. That data set is then input to OrcaFlex, to be used in time domain analysis.

The RAO and QTF data can be specified by period in seconds, by angular frequency in radians/second or by frequency in hertz. RAO & QTF phases. The RAO & QTF phase convention is specified by three data items: Phases are either …

OrcaFlex calculates the vessel primary motion in only three degrees of freedom (surge, sway, yaw) based on the included effects plus loads from any child objects connected to the vessel. There is no primary motion in heave, roll, or pitch. The data for each of the the included effects must be defined. Calculated (6 DOF).

2016年11月1日 · Compared fixed, time variant and interpolated local frequencies in single summation. This paper compares five numerical methods for calculating drift forces in time domain analysis of moored bodies. The first method is the most basic one. It uses all terms of QTF (quadratic transfer function) matrix based on double summation.

2012年10月15日 · It has been found that the low (difference) frequency components of the incident waves can excite the resonant response of floating platforms in their horizontal modes (surge, sway, and yaw). This phenomenon is called low-frequency drift response.

•FDG is one of the three wave drift loads applied to the body CoG, corresponding to FDy (surge), FDz (sway) or MDθ (yaw). •QTFG(αk,ωk) is the QTF value for relative wave incidence αk (wave direction relative to the instantaneous body orientation) and …

2021年11月7日 · In order to investigate the effects of second-order hydrodynamic loads on a 15 MW floating offshore wind turbine (FOWT), this study employs a tool that integrates AQWA and OpenFAST to conduct fully coupled simulations of the FOWT subjected to …

2019年10月30日 · Quadratic Transfer Functions (QTF) are generated for each combination of two incident wave frequencies and subsequently, a QTF matrix is computed. For uni-directional seas the drift force for each pair of wave frequencies (i, j) is defined as the product of the pair of incident wave heights \((\eta )\) and the corresponding QTF component, i.e ...

2020年9月16日 · The hydrodynamic loads were computed by summarizing forces from the wave radiation added mass and damping, the first-order wave loads, the second-order hydrodynamic quadratic transfer function (QTF), and the additional viscous force based on the viscous drag term of Morison’s equation.

Validation of the identified QTF is provided by comparing low frequency motions reconstructed from the empirical QTF with measurements. The numerical QTFs are calculated by a panel code that solves the wave- structure potential flow problem up to the second order.