Research

Development of a service performance simulator of ships

If a ship's voyage can be simulated on a "time" basis, it will be possible to rationally clarify the causal relationships among operational scenarios, encountered sea conditions, and service performance. We can provide useful information for the research and development of hull forms and the development of new routes. Service performance should be evaluated from a long-term perspective. They are specifically such as fuel consumption (economic efficiency), maximum swing and average period (safety, comfort), and voyage time (punctuality, reliability). In addition to the propulsion performance as a transport vessel, such performance is greatly related to operational scenarios and stormy weather avoidance. We will establish a method of service performance simulation that incorporates the rational combination and mutual influence of these, and consider what is the optimal service performance of a ship.

The principle of the simulator is to solve the equilibrium of forces under the constraints of the operational scenario. The ship's speed is obtained by solving the equilibrium between the resistance induced by waves, winds and current, the propeller thrust, and the engine torque. The interaction of resistance, propulsion, and engine motion and the operational scenarios are important. It is also necessary to simulate waves, winds and current, but it is not always necessary to use actual waves, winds and current data. For the performance evaluation of a ship, it is essential to give it a disturbance with equivalent characteristics. The figure shows an example of stochastically generating waves, winds and current and sailing a ship in it.

If a voyage can be simulated in the scale of “seconds”, it will be possible to predict the behavior of a ship in response to each wave it encounters, which will contribute to safe voyages. In the field of seakeeping research, analytical theories for estimating the behavior and loads of ships in waves have been constructed based on hydrodynamics and kinematics. Utilizing this knowledge, we will develop a simulator that obtains the behavior and load in waves in real time. Again, the state-space model is useful here.

If a voyage can be simulated in the scale of “seconds”, it will be possible to predict the behavior of a ship in response to each wave it encounters, which will contribute to safe voyages. In the field of seakeeping research, analytical theories for estimating the behavior and loads of ships in waves have been constructed based on hydrodynamics and kinematics. Utilizing this knowledge, we will develop a simulator that obtains the behavior and load in waves in real time. Again, the state-space model is useful here.

By considering a ship's service performance in a wide range of the scale from “seconds” to “hours”, we can comprehensively simulate service performance in actual seas.

Contact person: Munehiko Minoura