Abstract While maneuvering or positioning in different situations, the hull, the angle of the inlet current, and the tunnel opening fairing onto the hull have serious impacts on the performance of the bow thruster. The co-operation of multiple bow thrusters affects each other in the hydrodynamic performance. In this study, we report a thorough investigation of the hydrodynamic performance of the bow thruster combining experimental and numerical methods. The influence of the hull, the inflow angle, and the fillet radius of the tunnel opening is considered. The interaction between multiple bow thrusters is also studied. Open water tests and single bow thruster tests with the hull at eight different inflow angles were performed. Numerical simulations under the same condition were performed using the u-RANS method, and the accuracy of numerical results is verified by comparing with experimental data. Then, the flow field details of the single bow thruster condition were extracted. By analyzing the velocity distribution in the tunnel, the coupling influence of the hull and the inflow angle can be studied. Moreover, numerical simulations were performed for four hull models with different fillet radii for the tunnel opening. The influence of the opening fairing is analyzed by comparing numerical results and detailed flow fields. Finally, the co-operation of two bow thrusters is simulated, and the interaction between three bow thrusters is investigated. The results show that the joint influence will lead to a large-scale, asymmetric reversed flow zone at the tunnel opening. The reversed flow zone changes with the inflow angle and leads to a great difference in pressure distribution for different blades of the propeller. The opening fairing of the tunnel can improve the uniformity of the flow field in the tunnel, restrain the asymmetric pressure distribution on the propeller, and raise the efficiency of bow thruster. In addition, during co-operation, the induced flow direction of the propeller has a significant influence on the performance of the bow thruster. The upstream bow thruster can slightly improve the efficiency of the downstream bow thruster.

中文翻译：

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船首推进器水动力特性的实验与数值研究

摘要 在不同情况下操纵或定位时，船体、进水流角度以及船体上的隧道开口整流罩对船首推进器的性能有严重影响。多个船首推进器的配合在水动力性能上相互影响。在这项研究中，我们报告了结合实验和数值方法对船首推进器的水动力性能的彻底调查。考虑了船体、入流角和隧道开口圆角半径的影响。还研究了多个船首推进器之间的相互作用。进行了开放水域测试和单船首推进器测试，船体处于八个不同的流入角度。使用u-RANS方法进行相同条件下的数值模拟，并通过与实验数据的对比验证了数值结果的准确性。然后，提取单艏推进器条件的流场​​细节。通过分析隧道内的速度分布，可以研究船体与入流角的耦合影响。此外，对隧道开口不同圆角半径的四种船体模型进行了数值模拟。通过比较数值结果和详细的流场，分析了开口整流罩的影响。最后，模拟了两个船首推进器的协作，并研究了三个船首推进器之间的相互作用。结果表明，联合影响将导致隧道洞口处出现大规模的、不对称的逆流区。逆流区随着流入角的变化而变化，导致螺旋桨不同叶片的压力分布差异很大。隧道开口整流罩可以提高隧道内流场的均匀性，抑制螺旋桨上的不对称压力分布，提高艏侧推效率。此外，在配合过程中，螺旋桨的诱导流向对船首推进器的性能有显着影响。上游船首推进器可以稍微提高下游船首推进器的效率。此外，在配合过程中，螺旋桨的诱导流向对船首推进器的性能有显着影响。上游船首推进器可以稍微提高下游船首推进器的效率。此外，在配合过程中，螺旋桨的诱导流向对船首推进器的性能有显着影响。上游船首推进器可以稍微提高下游船首推进器的效率。