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Impact of hydrodynamics on ship handling characteristics in training simulators

Kobyliński L.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

2016

nr 45 (117)

9--16

Currently, ship operators (ship masters and pilots) are trained on ship simulators, either Full Mission Bridge (FMB) simulators, or Manned Model (MM) simulators. Both types of simulator increase an operator’s skill in manoeuvring a ship, and both incorporate the impact of hydrodynamic forces on the handling characteristics of a simulated ship. However, all forces affecting manoeuvring are the result of flow patterns that build up around the hull. These flow patterns may have extremely complex effects on many practical manoeuvres. Recent advances in hydrodynamic theory allow the impact of hydrodynamic forces on manoeuvrability to be simulated quite accurately so long as the simulated ship is moving straight ahead or performing standard manoeuvres. These advances also allow the simulation of such external influences as bank effects, shallow water effects, and canal effects, as well as the effect of the passage of other ships in the immediate vicinity. With a measure of simplification, these effects can be incorporated in FMB simulators. They can also be simulated by MM simulators provided both the models and training areas are properly prepared. As they are now, training simulators do not contribute to a trainee’s understanding of the way in which flow patterns develop or of the forces they create. This article discusses this deficiency and proposes a solution for it. Several examples of specific manoeuvring scenarios are used to illustrate the solution.

The analytical study on the optimal ballistic performance using interface theory

Hegde G. S., Narasimha Murthy H. N., Krishna M.

Journal of Achievements in Materials and Manufacturing Engineering

2010

Vol. 41, nr 1-2

112-123

Purpose: Analytical determination of impact velocity for different combination of target and projectile materials is the objective of this paper. Design/methodology/approach: The penetration efficiency is maximum when the interaction between the projectile and target is hydrodynamic. Considering zero strength for target and projectile the hydrodynamic impact velocities are predicted using hydrodynamic equation of state. Findings: The hydrodynamic equation being an indeterminate equation is solved using interface theory (briefed in the appendix). The indeterminate Johnson-Cook (JC) model and Steinberg-Guinian (SG) model are also solved using interface theory to predict the influence of static strength of projectile and thermal softening effects. It is inferred that the penetration efficiency decreases with increasing static strength of target and also due to thermal softening of the projectile. In the process the plastic strain, the strain rate and the increase in temperature during impact are theoretically predicted. The segmented projectiles have less/more penetration efficiency than the monolithic impactors and hence require higher/lower impact velocities nearing to hydrodynamic state. Research limitations/implications: The analytical results obtained are in fair agreement with experimental results obtained in the reviewed literatures. Some contrasts are also observed. Originality/value: The paper present the analytical study on the optimal ballistic performance using interface theory.