Combined Steady State and Transient Analysis of a Patrol Vessel as Affected by Varying Amounts of Damping and Periodic and Random Wave Excitation

Author(s):  
Jeffrey M. Falzarano ◽  
Srinivas Vishnubhotla ◽  
Sarah E. Juckett

In this paper various techniques of dynamical system analysis are used to analyze the effect of damping on large amplitude nonlinear ship-rolling motion of a patrol vessel. In particular steady state magnification curves, Poincare maps are for harmonic forcing and project phase planes are for random forcing. It has been found that varying amounts of damping substantially affect the vessel’s critical behavior. This is important since most stability regulations ignore damping and solely concentrate on the vessel’s righting ram curve. Moreover roll damping is difficult to predict accurately and small changes in damping may have a significant effect.

1996 ◽  
Vol 40 (01) ◽  
pp. 46-59 ◽  
Author(s):  
K. J. Spyrou

The dynamic stability of ships encountering large regular waves from astern is analyzed, with focus on delineating the specific conditions leading to the uncontrolled turn identified as broaching. The problem's formulation takes into account motions of the actively steered or controls-fixed vessel in surge-sway-yaw-roll with consideration of Froude-Krylov and diffraction wave excitation. Dynamical analysis of surf-riding is carried out for the general case of quartering waves, exploring the route periodic motions—surf riding, loss of stationary stability, turn, capsize. Steady-state and transient analysis is carried out in the system's multidimensional state-space in order to identify all existing limit sets and locate attracting domains. Broaching from periodic motions is also a part of the investigation.


Author(s):  
J. Falzarano ◽  
R. Kota ◽  
I. Esparza

Abstract For ships, rolling motion is the most critical due to the possibility of capsizing. In a regular (periodic) sea, if no bounded steady state solutions exist, then capsizing may be imminent. Determining for exactly which wave amplitude and frequency the steady-state solutions disappear or become unstable is of great practical importance. In previous works (Falzarano, Esparza, and Taz Ul Mulk, 1994) and abstracted presentations (Falzarano, 1993), the global transient dynamics of large amplitude ship rolling motion was studied. The effect on the steady-state solutions of changing wave frequency for a fixed wave amplitudes was studied. It was shown how the in-phase and out-of-phase solutions evolve as the frequency passes through the linear natural frequency. For small wave amplitudes (external forcing) there exists a single steady-state throughout the frequency range, for moderate wave amplitudes there exists a frequency range where multiple steady state harmonic solutions exists. As the wave amplitude was increased further there existed a frequency range where no steady-state harmonic solution existed. In the present work, the very large amplitude ship rolling motion in the region where no steady-state solutions exist will be studied in more detail. Moreover, the mechanisms (bifurcations) that cause this type of behavior to evolve from more simple behavior will be studied using a combination of both frequency response curves and Poincaré maps. It is expected that global chaotic bifurcations such as those previously described (e.g., Thompson and Stewart, 1989) will be identified.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ali Osman Yılmaz ◽  
Ertan Güdekli

AbstractWe investigate Friedmann–Lamaitre–Robertson–Walker (FLRW) models with modified Chaplygin gas and cosmological constant, using dynamical system methods. We assume $$p=(\gamma -1)\mu -\dfrac{A}{\mu ^\alpha }$$ p = ( γ - 1 ) μ - A μ α as equation of state where $$\mu$$ μ is the matter-energy density, p is the pressure, $$\alpha$$ α is a parameter which can take on values $$0<\alpha \le 1$$ 0 < α ≤ 1 as well as A and $$\gamma$$ γ are positive constants. We draw the state spaces and analyze the nature of the singularity at the beginning, as well as the fate of the universe in the far future. In particular, we address the question whether there is a solution which is stable for all the cases.


1985 ◽  
Vol 50 ◽  
Author(s):  
J-E. Andersson ◽  
O. Persson

AbstractThe results from a large number of single-hole packer tests in crystalline rock from three test sites in Sweden have been analysed statistically. Average hydraulic conductivity values for 25 m long test intervals along boreholes with a maximal length of about 700 m are used in this study. A comparison between steady state and transient analysis of the same test data has been performed.The mean vaule of the hydraulic conductivity determined from steady state analysis was found to be about two to three times higher compared to transient analysis. However, in some cases the steady state analysis resulted in 10 to 20 times higher values compared to the transient analysis. Such divergence between the two analysis methods may be caused by deviations from the assumed flow pattern, borehole skin effects and influence of hydraulic boundaries.


2009 ◽  
Vol 29 (3) ◽  
pp. 370-376 ◽  
Author(s):  
Sheri P. Silfies ◽  
Anand Bhattacharya ◽  
Scott Biely ◽  
Sue S. Smith ◽  
Simon Giszter

2021 ◽  
pp. 1-23
Author(s):  
Daniel O'Reilly ◽  
Manouchehr Haghighi ◽  
Mohammad Sayyafzadeh ◽  
Matthew Flett

Summary An approach to the analysis of production data from waterflooded oil fields is proposed in this paper. The method builds on the established techniques of rate-transient analysis (RTA) and extends the analysis period to include the transient- and steady-state effects caused by a water-injection well. This includes the initial rate transient during primary production, the depletion period of boundary-dominated flow (BDF), a transient period after injection starts and diffuses across the reservoir, and the steady-state production that follows. RTA will be applied to immiscible displacement using a graph that can be used to ascertain reservoir properties and evaluate performance aspects of the waterflood. The developed solutions can also be used for accurate and rapid forecasting of all production transience and boundary-dominated behavior at all stages of field life. Rigorous solutions are derived for the transient unit mobility displacement of a reservoir fluid, and for both constant-rate-injection and constant-pressure-injection after a period of reservoir depletion. A simple treatment of two-phase flow is given to extend this to the water/oil-displacement problem. The solutions are analytical and are validated using reservoir simulation and applied to field cases. Individual wells or total fields can be studied with this technique; several examples of both will be given. Practical cases are given for use of the new theory. The equations can be applied to production-data interpretation, production forecasting, injection-water allocation, and for the diagnosis of waterflood-performanceproblems. Correction Note: The y-axis of Fig. 8d was corrected to "Dimensionless Decline Rate Integral, qDdi". No other content was changed.


2020 ◽  
Vol 80 (9) ◽  
Author(s):  
Soumya Chakraborty ◽  
Sudip Mishra ◽  
Subenoy Chakraborty

AbstractA cosmological model having matter field as (non) interacting dark energy (DE) and baryonic matter and minimally coupled to gravity is considered in the present work with flat FLRW space time. The DE is chosen in the form of a three-form field while radiation and dust (i.e; cold dark matter) are the baryonic part. The cosmic evolution is studied through dynamical system analysis of the autonomous system so formed from the evolution equations by suitable choice of the dimensionless variables. The stability of the non-hyperbolic critical points are examined by Center manifold theory and possible bifurcation scenarios have been examined.


1977 ◽  
Vol 10 (2) ◽  
pp. 44-50 ◽  
Author(s):  
C. McCorkell ◽  
N. Wilson

Dynamical system analysis is included in undergraduate courses in the Northern Ireland Polytechnic, as part of a presentation of general engineering methodology and more particularly, accompanied by synthesis techniques, in control options at final year honours level. Such is the extent of the computational requirement, necessary for a non-trivial treatment, that steps have been taken to introduce computer usage where possible. Included is information on the initial stage of a project undertaken to provide for the computational needs of undergraduates involved in dynamical problems in the laboratory.


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