Experimental Investigation of Propeller Wake Wash

螺旋桨尾流洗流实验研究

• 批准号: RGPIN-2016-03905
• 负责人: Veitch, Brian
• 金额: $ 2.11万
• 依托单位: Memorial University of Newfoundland
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=683091
• 关键词: Experimental; Investigation; Propeller; Wake; Wash

Navigation in ice-covered waters requires that vessels be capable of operating in natural ice conditions, such as broken pack ice and intact level ice. Conventional ice-breaking operations rely largely on the mass and power of the vessel to break through ice. The ship's structure must be correspondingly strong. Recent innovations in marine propulsion technology have provided opportunities to use propeller wake wash as another means to break, clear, and otherwise manage ice. Icebreaking operations employing propeller wake wash can reduce significantly the ship structure-ice interaction involved in conventional icebreaking, thereby reducing the likelihood of structural damage and accidental spills of fuel or cargo, and improving the operation's energy efficiency. Propeller wake wash has been used for years by mariners to clear broken ice from shipping channels, but it has only been since the advent of azimuthing types of propulsors that it has been incorporated into operations by design. At present, the design is done on an ad hoc basis as there is limited fundamental understanding of how the wake wash develops downstream of the propeller and subsequently interacts with sea ice at the free surface. The proposed research will address this knowledge gap. *******The proposed research will characterize propeller wake wash in terms of the 3-D fluid velocity field downstream, including the velocity field at the free surface. The characterization will be based on laboratory experiments. Experiments will be done in the tow tank at Memorial University's Ocean Engineering Research Centre. Experiments will focus first on the propeller wake wash in the absence of ice, and then on the interactions of the wake wash and ice. The focus of interest in terms of ice features will be on pack ice. A semi-empirical mathematical model will be developed of the downstream wake, and the interaction between the flow at the free surface and its interaction with pack ice. The model of the wake wash field will include mean velocities, as well as of its variability throughout the downstream wake. It will be tested against field observations of ships in ice, as the final experimental element of the proposed work. The wake model will predict the downstream surface velocity field in terms of key factors: delivered power, depth of submergence of the propeller, and inclination angle of the propeller to the free surface. When coupled to the ice interaction model, the model should predict how wake wash can clear pack ice en masse downstream from the propeller. This will be useful for designers and operators, such as commercial shipping, the Coast Guard, Navy and others who navigate in ice in connection with transportation, exploration and defense.******The proposed research covers a 5 year time span. Four Master's students will work on this program. All graduate students will be in a thesis-based degree program.

在冰覆盖水域航行要求船舶能够在自然冰况下作业，例如破碎的浮冰和完整的平冰。传统的破冰作业很大程度上依靠船舶的质量和动力来破冰。船舶的结构必须相应坚固。船舶推进技术的最新创新提供了使用螺旋桨尾流冲洗作为破冰、清除和以其他方式管理冰的另一种手段的机会。采用螺旋桨尾流冲洗的破冰作业可以显着减少传统破冰中涉及的船舶结构与冰的相互作用，从而减少结构损坏和燃料或货物意外泄漏的可能性，并提高作业的能源效率。多年来，海员一直使用螺旋桨尾流清洗来清除航道中的碎冰，但直到全向型推进器出现后，它才被设计纳入运营中。目前，该设计是在临时基础上完成的，因为对尾流如何在螺旋桨下游发展以及随后与自由表面的海冰相互作用的基本了解有限。拟议的研究将解决这一知识差距。 ******拟议的研究将根据下游 3-D 流体速度场（包括自由表面的速度场）来表征螺旋桨尾流冲刷。表征将基于实验室实验。实验将在纪念大学海洋工程研究中心的拖曳水池中进行。实验将首先关注没有冰的情况下的螺旋桨尾流，然后研究尾流与冰的相互作用。就冰特征而言，人们关注的焦点将是浮冰。将开发下游尾流、自由表面流动及其与浮冰相互作用之间的相互作用的半经验数学模型。尾流冲刷场的模型将包括平均速度及其在整个下游尾流中的变化。它将针对冰中船舶的现场观察进行测试，作为拟议工作的最终实验要素。尾流模型将根据关键因素预测下游表面速度场：传递功率、螺旋桨浸没深度以及螺旋桨相对于自由表面的倾斜角。当与冰相互作用模型耦合时，该模型应预测尾流冲洗如何清除螺旋桨下游的大量浮冰。 这对于商业航运、海岸警卫队、海军和其他在冰上航行的运输、勘探和国防领域的设计者和操作者来说非常有用。******拟议的研究涵盖了 5 年的时间跨度。四名硕士生将参与该项目。所有研究生都将参加基于论文的学位课程。