A Volterra series approach to the frequency domain analysis of non-linear viscous Burgers’ equation

2012 ◽  
Vol 70 (3) ◽  
pp. 1753-1765 ◽  
Author(s):  
L. Z. Guo ◽  
Y. Z. Guo ◽  
S. A. Billings ◽  
D. Coca ◽  
Z. Q. Lang
Keyword(s):  
Frequency Domain ◽  
Burgers Equation ◽  
Volterra Series ◽  
Domain Analysis ◽  
Frequency Domain Analysis ◽  
Non Linear

scholarly journals Numerical Study of Non-Linear Dynamic Behavior of an Asymmetric Rotor for Wave Energy Converter in Regular Waves

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1477
Author(s):  
Yoon-Jin Ha ◽  
Ji-Yong Park ◽  
Seung-Ho Shin
Keyword(s):  
Frequency Domain ◽  
Wave Height ◽  
Cfd Simulation ◽  
Domain Analysis ◽  
Frequency Domain Analysis ◽  
Linear Motion ◽  
Regular Waves ◽  
Cfd Simulations ◽  
Non Linear ◽  
Wave Heights

This study conducted a numerical investigation on the non-linear motion problems between a Salter duck-type rotor and large waves using CFD simulations. Regular waves of five different wave heights were generated. First, the linear motion of the rotor from the CFD simulation was verified by comparing it with the existing experimental and frequency domain analysis results. Then, a series of CFD simulations were performed to investigate the non-linear motions of the rotor. In the case of a lower wave height, the CFD simulation results were in good agreement with the experimental and frequency domain analysis results. However, as the wave height increased, the resonance periods were different in each other. In addition, the magnitudes of normalized pitch motions by the wave heights decreased as the wave heights increased. To investigate the aforementioned phenomena, the pitch motion equation was examined using separate CFD simulations. The results showed that changing the restoring moments induced changes in the maximum pitch motions and magnitudes of the normalized pitch motions. In the case of a higher wave height, non-linear phenomena and the changing restoring moments induced non-linear motion.

TIME-SEGMENTED FREQUENCY-DOMAIN ANALYSIS FOR NON-LINEAR MULTI-DEGREE-OF-FREEDOM STRUCTURAL SYSTEMS

2000 ◽  
Vol 237 (3) ◽  
pp. 457-475 ◽  
Author(s):  
W.J. MANSUR ◽  
J.A.M. CARRER ◽  
W.G. FERREIRA ◽  
A.M. CLARET DE GOUVEIA ◽  
F. VENANCIO-FILHO
Keyword(s):  
Frequency Domain ◽  
Domain Analysis ◽  
Frequency Domain Analysis ◽  
Degree Of Freedom ◽  
Structural Systems ◽  
Non Linear

Coupled Dynamic Analysis of a Moored Spar in Random Waves and Currents (Time-Domain Versus Frequency-Domain Analysis)

1999 ◽  
Vol 121 (3) ◽  
pp. 194-200 ◽  
Author(s):  
Z. Ran ◽  
M. H. Kim ◽  
W. Zheng
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Software Package ◽  
Volterra Series ◽  
Domain Analysis ◽  
Frequency Domain Analysis ◽  
Random Waves ◽  
Mooring Lines ◽  
Drag Forces ◽  
The Time Domain

Nonlinear coupled responses of a moored spar in random waves with and without colinear currents are investigated in both time and frequency domains. The first and second-order wave forces, added mass and radiation damping, and wave drift damping are calculated from a hydrodynamics software package called WINTCOL. The total wave force time series (or spectra) are then generated in the time (or frequency) domain based on a two-term Volterra series model. The mooring dynamics are solved using the software package WINPOST, which is based on a generalized-coordinate-based finite element method. The mooring lines are attached to the platform through linear and rotational springs and dampers so that various boundary conditions can be modeled using proper spring and damping values. In the time-domain analysis, the nonlinear drag forces on the hull and mooring lines are applied at the instantaneous position. In the frequency-domain analysis, nonlinear drag forces are stochastically linearized, and solutions are obtained by an iterative procedure. The time-domain results are systematically compared with the frequency-domain results.

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