scholarly journals NON-LINEAR WAVE FORCES ON FLOATING BREAKWATERS

1982 ◽  
Vol 1 (18) ◽  
pp. 120
Author(s):  
C.T. Niwinski ◽  
M. De St. Q. Isaacson
Keyword(s):  
Wave Train ◽  
Wave Forces ◽  
Linear Wave ◽  
Floating Bodies ◽  
Time Stepping ◽  
Non Linear ◽  
Force Curves ◽  
Accuracy Of Results ◽  
Floating Breakwaters ◽  
Linear Nature

A non-linear numerical method for calculating wave forces on floating bodies has been developed by Isaacson (1981). The time stepping procedure is programmed for a computer solution, and an incident wave train is time stepped past a fixed two-dimensional rectangular breakwater. The influence of various input parameters on the accuracy of results is investigated, and optimal values of the parameters are determined. The optimal numerical parameters are used to generate force and transmission coefficient results, which are compared to the results of other published studies. The method is shown to compare favorably with other results, with the non-linear nature of the method being clearly demonstrated by the different force curves produced by varying the wave height.

scholarly journals ACCURATE PREDICTION OF NON-LINEAR WAVE FORCES: PART II (RESPONDING CYLINDER)

1998 ◽  
Vol 12 (3) ◽  
pp. 487-498 ◽  
Author(s):  
S.A. Billings ◽  
P.K. Stansby ◽  
A.K. Swain ◽  
M. Baker
Keyword(s):  
Accurate Prediction ◽  
Wave Forces ◽  
Linear Wave ◽  
Non Linear

scholarly journals Influence of Viscosity and Non-Linearities in Predicting Motions of a Wind Energy Offshore Platform in Regular Waves

2018 ◽  
Author(s):  
José del Águila Ferrandis ◽  
Ricardo Zamora Rodríguez ◽  
Chryssostomos Chryssostomidis ◽  
Luca Bonfiglio
Keyword(s):  
Frequency Domain ◽  
Stokes Equations ◽  
Offshore Platform ◽  
Operating Conditions ◽  
Boundary Element Methods ◽  
Linear Wave ◽  
Floating Bodies ◽  
Computational Costs ◽  
Non Linear ◽  
Flow Theories

Motion prediction of floating bodies in waves represents one of the most challenging problems in naval hydrodynamics. The solution of the seakeeping problem involves the study of complex non-linear wave-body interactions that require large computational costs. For this reason, over the years many seakeeping models have been formulated in order to predict ship motions using simplified flow theories, usually based on potential flow theories solved within the linear assumption. Neglecting viscous effects in the computation of radiation forces might largely underestimate the energy dissipated by the system while moving at the free surface. This problem is particularly relevant for unconventional floating bodies at resonance. In these operating conditions the linear assumption is no longer valid and conventional Boundary Element Methods, solved in the frequency domain, might predict unrealistic large responses if not corrected with empirical damping coefficients. The application considered in this study is an offshore platform to be operated in a wind farm requiring operability even in extreme meteorological conditions. In this paper, we compare heave and pitch Response Amplitude Operators, predicted for an offshore platform using three different seakeeping models of increasing complexity; namely a frequency-domain BEM, a high-order BEM solved in time-domain and a non-linear fully viscous model based on the solution of the Unsteady Reynolds Averaged Navier-Stokes equations (URANS). Results are critically compared in terms of accuracy, applicability and computational costs.

scholarly journals ACCURATE PREDICTION OF NON-LINEAR WAVE FORCES: PART I (FIXED CYLINDER)

1998 ◽  
Vol 12 (3) ◽  
pp. 449-485 ◽  
Author(s):  
A.K. Swain ◽  
S.A. Billings ◽  
P.K. Stansby ◽  
M. Baker
Keyword(s):  
Accurate Prediction ◽  
Wave Forces ◽  
Linear Wave ◽  
Non Linear ◽  
Fixed Cylinder
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