The goal of this study is to investigate ship propulsion system dynamics under sea wave conditions by including the interaction of hull, propeller, and engine. A mathematical ship propulsion system model was made and the related computer code was developed. To get the results as close as possible to real conditions, measured data for physical models, including the ship’s resistance in calm and sea waves and propeller performance, were implemented in the model. For a diesel engine, performances provided by the manufacturer were used. The wave force time series, as exciting force, changed the propulsion system state from steady to transient. It activated system variables including ship’s speed, advance number, propeller and engine torque, propeller and engine rotational speeds, effective and generated powers, and net thrust. The analysis was performed for a container ship for two regular waves. Using the developed computer code, the ship’s speed and system variables, as well as the consumed fuel and the voyage distance, were calculated and compared with the calm water condition. The voyage mode was set on constant rotational engine speed implementing a P-action governor with fuel rate and engine torque limiters. The outcomes of the research explain the influence of the governor and its limiters on fuel consumption, identify the nonlinear impact of sea waves on propeller characteristics, and underline the effect of voyage mode on system response and the consumed fuel. The results also show that the conventional method for calculating speed reduction based on the added resistance is not capable of justifying the system’s dynamic behaviour.

中文翻译：

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通过实验和模拟相结合的方法分析规则波浪中的船体、螺旋桨和发动机相互作用

本研究的目的是通过包括船体、螺旋桨和发动机的相互作用来研究海浪条件下的船舶推进系统动力学。建立了船舶推进系统的数学模型并开发了相关的计算机代码。为了使结果尽可能接近真实条件，模型中采用了物理模型的测量数据，包括船舶在平静和海浪中的阻力以及螺旋桨性能。对于柴油发动机，使用制造商提供的性能。波浪力时间序列作为激振力，将推进系统的状态从稳态转变为瞬态。它激活了系统变量，包括船速、前进数、螺旋桨和发动机扭矩、螺旋桨和发动机转速、有效功率和发电功率以及净推力。对一艘集装箱船进行了两次规则波浪的分析。使用开发的计算机代码，计算船舶的速度和系统变量，以及消耗的燃料和航行距离，并与平静的水面条件进行比较。航行模式设置在恒定的发动机转速上，采用带有燃油率和发动机扭矩限制器的 P 动作调节器。研究结果解释了调速器及其限制器对燃料消耗的影响，确定海浪对螺旋桨特性的非线性影响，并强调航行模式对系统响应和消耗燃料的影响。结果还表明，基于增加的阻力计算减速的传统方法不能证明系统的动态行为是合理的。