An Investigation on the Discrepancies Between RANSE and BEM Approaches for the Prediction of Marine Propeller Unsteady Performances in Strongly Non-Homogeneous Wakes
An Investigation on the Discrepancies Between RANSE and BEM Approaches for the Prediction of Marine Propeller Unsteady Performances in Strongly Non-Homogeneous Wakes
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DOI：
10.1115/omae2014-23831
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发表时间：
2014-06
期刊：
影响因子：
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通讯作者：
S. Gaggero;D. Villa;M. Viviani
中科院分区：
文献类型：
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作者：
S. Gaggero;D. Villa;M. Viviani
本文分析了不同的数值方法，即边界元法和RANSE求解法，用于船舶螺旋桨非定常性能预测的可靠性。为此，我们考虑了著名的Seiun-Maru高倾斜螺旋桨在不同尾流中运行。分析结果表明，在特殊的条件下，即当存在非常明显的船舶尾迹时，这两种方法在螺旋桨机械特性和叶片压力分布方面可能会提供相当不同的结果。这一问题在采用推力同一性方法（例如，对于旨在评估空化扩展和/或诱导压力的螺旋桨分析，几乎总是采用这种方法）时可以隐式消除，但在将代码用于数值自推进试验时可能变得至关重要，因为在这种情况下，根据预先系数的规定值而不是推力系数来预测非定常螺旋桨性能的精度很高。是强制性的。所进行的分析可以强调在尾迹特征方面哪些可能是更有问题的情况，并提出遇到差异的一些可能原因，这些原因需要进一步分析以提高数值代码的预测能力。ASME版权所有©2014
In the present work an analysis of the reliability of different numerical approaches, namely BEM and RANSE solver, for the prediction of unsteady performances of marine propellers is presented. To this aim, the well-known Seiun-Maru Highly Skewed Propeller operating in different wakes is considered. The results of this analysis show that, in correspondence to particularly challenging conditions, i.e. when very pronounced ship wakes are present, the two approaches may provide considerably different results in terms of propeller mechanical characteristics and pressure distributions on the blades. This problem, which is implicitly eliminated when the thrust identity approach is applied (as almost always performed, as an example, for propeller analyses aimed to the evaluation of cavitation extension and / or induced pressures), may become critical in case the codes are used for numerical self-propulsion tests, where a high accuracy in the prediction of the unsteady propeller performances in correspondence to a prescribed value of the advance coefficient, instead of the thrust coefficient, is mandatory. The analyses carried out allow to underline which are the potentially more problematic cases, in terms of wakes characteristics, and to suggest some possible reasons of the encountered discrepancies, which will need further analyses to enhance the prediction capability of numerical codes.Copyright © 2014 by ASME