Abstract Maritime transport is the most energy-effective mode to move large amounts of goods around the world. Hauling cargo via waterway produces an enormous quantity of greenhouse gas emissions. Vessel fuel efficiency directly influences ship emissions by affecting the amount of burnt fuel. Optimizing ships operating in waves rather than in calm water conditions could decrease the fuel consumption of vessels. In particular, ship propellers are traditionally designed neglecting dynamic conditions such as time-varying wake distribution and propulsion factors, propeller speed fluctuations, ship motions, and speed loss. The effect of waves on the propeller performance can be evaluated using both a quasi-steady and a fully-unsteady approach. The former is a fast computational approximation method based on the assumption that the ratio of propeller angular frequency to wave encounter frequency is sufficiently large. The latter provides a complete representation of the propeller dynamics, but it is computationally expensive. The purpose of this paper is to compare the propeller performance in the presence of waves using the quasi-steady and the fully unsteady approach. This analysis is performed by observing the differences in unsteady propeller forces, cavitation volume, and hull pressure pulses between the two approaches. The full-scale KVLCC2 propeller is utilized for the investigation. Results show a good agreement between the quasi-steady and the fully-unsteady approach in the prediction of the temporal mean and the fluctuation amplitude of KT and KQ, the cavity volume variation, and the hull pressure pulses. Therefore, for the considered operating conditions, the quasi-steady approach can be used to compute the propeller performance in waves.

中文翻译：

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全非定常和准定常方法在波浪中预测螺旋桨性能的比较

摘要 海运是在世界范围内运输大量货物的最节能的方式。通过水路运输货物会产生大量的温室气体排放。船舶燃料效率通过影响燃烧燃料的量直接影响船舶排放。优化在波浪中而不是在平静水域条件下运行的船舶可以减少船舶的燃料消耗。特别是，船舶螺旋桨的传统设计忽略了动态条件，例如随时间变化的尾流分布和推进因素、螺旋桨速度波动、船舶运动和速度损失。波浪对螺旋桨性能的影响可以使用准稳态和完全非稳态方法进行评估。前者是一种基于螺旋桨角频率与波浪遭遇频率之比足够大的假设的快速计算近似方法。后者提供了螺旋桨动力学的完整表示，但计算成本很高。本文的目的是使用准稳态和完全非稳态方法比较存在波浪时的螺旋桨性能。该分析是通过观察两种方法之间非定常螺旋桨力、空化体积和船体压力脉冲的差异来进行的。全尺寸 KVLCC2 螺旋桨用于调查。结果表明，准稳态和全非稳态方法在预测 KT 和 KQ 的时间平均值和波动幅度、腔体积变化、和船体压力脉冲。因此，对于所考虑的操作条件，准稳态方法可用于计算波浪中的螺旋桨性能。