Dynamic Instability in Quartering Seas: The Behavior of a Ship During Broaching

1996 ◽  
Vol 40 (01) ◽  
pp. 46-59 ◽  
Author(s):  
K. J. Spyrou
Keyword(s):  
Steady State ◽  
Transient Analysis ◽  
Dynamic Instability ◽  
Dynamical Analysis ◽  
Wave Excitation ◽  
Periodic Motions ◽  
Regular Waves ◽  
Limit Sets ◽  
Diffraction Wave ◽  
Surf Riding

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.

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

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Jeffrey M. Falzarano ◽  
Srinivas Vishnubhotla ◽  
Sarah E. Juckett
Keyword(s):  
Dynamical System ◽  
Steady State ◽  
Critical Behavior ◽  
Large Amplitude ◽  
Transient Analysis ◽  
System Analysis ◽  
Random Wave ◽  
Rolling Motion ◽  
Wave Excitation ◽  
Random Forcing

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.

Evaluation of Single-Hole Hydraulic Tests in Fractured Crystalline Rock by Steady-State and Transient Methods: A Comparison

1985 ◽  
Vol 50 ◽  
Author(s):  
J-E. Andersson ◽  
O. Persson
Keyword(s):  
Steady State ◽  
Hydraulic Conductivity ◽  
Flow Pattern ◽  
Transient Analysis ◽  
Crystalline Rock ◽  
Steady State Analysis ◽  
Single Hole ◽  
The Mean ◽  
Transient Methods ◽  
State Analysis

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.

Dynamic Instability in Quartering Seas—Part II: Analysis of Ship Roll and Capsize for Broaching

1996 ◽  
Vol 40 (04) ◽  
pp. 326-336
Author(s):  
K. J. Spyrou
Keyword(s):  
Design Methodology ◽  
Dynamic Instability ◽  
Global Analysis ◽  
Theoretical Background ◽  
Dynamic Effects ◽  
Arbitrary Initial Condition ◽  
Forced Turn ◽  
Surf Riding ◽  
Ship Roll ◽  
Ship Capsize

In earlier studies we have analyzed the phenomena which can generate loss of ship controllability in astern seas. In this paper we examine how the yaw instability associated with broaching can lead to roll instability and ship capsize. The dynamic effects responsible for capsize during the forced turn of broaching do not have their origin in the customary roll equation but are the result of interactions with other motions of the ship. Stability studies based solely on the roll equation are thus clearly inappropriate for this case where a multidimensional approach is deemed necessary. After presenting the theoretical background we set out a multi-degree method of global analysis which is based on transient maps. We apply this method to clarify how capsize occurs during the escape from surf-riding and also during transients from arbitrary initial condition of the ship. Our study establishes the connection between speed, heading, automatic control parameters and capsize. The proposed method can be useful in the context of a design methodology for minimizing the risk of ship capsize in astern seas.

Dynamical analysis of a reaction–diffusion SEI epidemic model with nonlinear incidence rate

2021 ◽  
pp. 2150041
Author(s):  
Jianpeng Wang ◽  
Binxiang Dai
Keyword(s):  
Steady State ◽  
Incidence Rate ◽  
Epidemic Model ◽  
Reaction Diffusion ◽  
Dynamical Analysis ◽  
Asymptotically Stable ◽  
Nonlinear Incidence Rate ◽  
Globally Asymptotically Stable ◽  
Nonlinear Incidence ◽  
Positive Steady State

In this paper, a reaction–diffusion SEI epidemic model with nonlinear incidence rate is proposed. The well-posedness of solutions is studied, including the existence of positive and unique classical solution and the existence and the ultimate boundedness of global solutions. The basic reproduction numbers are given in both heterogeneous and homogeneous environments. For spatially heterogeneous environment, by the comparison principle of the diffusion system, the infection-free steady state is proved to be globally asymptotically stable if [Formula: see text] if [Formula: see text], the system will be persistent and admit at least one positive steady state. For spatially homogenous environment, by constructing a Lyapunov function, the infection-free steady state is proved to be globally asymptotically stable if [Formula: see text] and then the unique positive steady state is achieved and is proved to be globally asymptotically stable if [Formula: see text]. Finally, two examples are given via numerical simulations, and then some control strategies are also presented by the sensitive analysis.

Analytical Rate-Transient Analysis and Production Performance of Waterflooded Fields with Delayed Injection Support

2021 ◽  
pp. 1-23
Author(s):  
Daniel O'Reilly ◽  
Manouchehr Haghighi ◽  
Mohammad Sayyafzadeh ◽  
Matthew Flett
Keyword(s):  
Steady State ◽  
Transient Analysis ◽  
Water Injection ◽  
Data Interpretation ◽  
Production Performance ◽  
Production Data ◽  
Reservoir Properties ◽  
Two Phase ◽  
Production Forecasting ◽  
Rate Transient Analysis

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.

scholarly journals Alternating Strain Regimes for Failure Propagation in Flexural Systems

2019 ◽  
Vol 72 (3) ◽  
pp. 305-339 ◽  
Author(s):  
M Garau ◽  
M J Nieves ◽  
I S Jones
Keyword(s):  
Steady State ◽  
Transient Analysis ◽  
Fracture Process ◽  
Mechanical Load ◽  
Dynamic Features ◽  
Hopf Equation ◽  
Beam Structure ◽  
Numerical Studies ◽  
Failure Propagation ◽  
Discrete Mass

Summary We consider both analytical and numerical studies of a steady-state fracture process inside a discrete mass-beam structure, composed of periodically placed masses connected by Euler–Bernoulli beams. A fault inside the structure is assumed to propagate with a constant speed and this occurs as a result of the action of a remote sinusoidal, mechanical load. The established regime of fracture corresponds to the case of an alternating generalised strain regime. The model is reduced to a Wiener–Hopf equation and its solution is presented. We determine the minimum feeding wave energy required for the steady-state fracture process to occur. In addition, we identify the dynamic features of the structure during the steady-state fracture regime. A transient analysis of this problem is also presented, where the existence of steady-state fracture regimes, revealed by the analytical model, are verified and the associated transient features of this process are discussed.

Transient and Steady-State Operational Limits for Ship Roll

1993 ◽  
Vol 46 (11S) ◽  
pp. S47-S52 ◽  
Author(s):  
Steven R. Bishop ◽  
Jesse Rebello de Souza
Keyword(s):  
Steady State ◽  
Numerical Methods ◽  
Basins Of Attraction ◽  
Ship Motion ◽  
Resonant Response ◽  
Regular Waves ◽  
Steady State Analysis ◽  
Small Vessels ◽  
Ship Roll ◽  
Transient And Steady State

This paper investigates the safe operational limits of roll for small vessels in regular waves through the use of an archetypal model of ship motion. The technique incorporates steady-state analysis with methods of quantifying the engineering integrity of transient motions. Both analytical and numerical methods are used and compared. The resonant response of the vessel is examined to reveal unacceptable solutions and superimposed on parameter space diagrams which include lower bounds for fractal erosion of basins of attraction.

The high magnetic coupling passive loop: A steady-state and transient analysis of the thermal behavior

2012 ◽  
Vol 37 ◽  
pp. 154-164 ◽  
Author(s):  
Aldo Canova ◽  
Fabio Freschi ◽  
Luca Giaccone ◽  
Alessandra Guerrisi
Keyword(s):  
Steady State ◽  
Thermal Behavior ◽  
Transient Analysis ◽  
Magnetic Coupling
Sign in / Sign up

Export Citation Format

Share Document