Assessment of aerodynamic roughness parameters of turbulent boundary layers over barnacle-covered surfaces
Assessment of aerodynamic roughness parameters of turbulent boundary layers over barnacle-covered surfaces
复制标题
藤壶覆盖表面湍流边界层气动粗糙度参数的评估
DOI：
10.1007/s00348-023-03709-5
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发表时间：
2023
影响因子：
2.4
通讯作者：
Medjnoun T
中科院分区：
文献类型：
--
作者：
Medjnoun T
粗糙壁面流动的全尺寸阻力损失预测需要通过实验室试验或数值模拟获得表面粗糙度特性。无论采用哪种方法，都必须确定所谓的等效砂粒粗糙度高度（）。确定空气动力学粗糙度长度尺度涉及几个步骤，但其程序通常包括使用直接或间接方法测量壁面剪应力（）以及分析速度剖面。间接方法通常依赖于对流动及其缩放的假设，包括通用外层相似性的有效性。然而，涉及全尺寸阻力预测的基本假设的含义尚不清楚。在这项工作中，我们进行了风洞测量在一个现实的粗糙表面（从一个污损船体），以评估不同的方法的影响，重点是使用外层相似性假设的全尺寸阻力预测。壁面剪应力的测量使用内部浮动元件阻力天平（DB），并获得速度剖面使用粒子图像测速（PIV），允许的评估，并通过几种方法相关的唤醒参数。由此获得的气动粗糙度参数用于全尺寸阻力损失计算。据观察，预测的阻力损失可以在不同的方法之间变化超过15%，强调了在使用这些方法时应注意的问题。
Full-scale drag penalty predictions of flows over rough walls require surface roughness characterisation from laboratory experiments or numerical simulations. In either approach, it is necessary to determine the so-called equivalent sand-grain roughness height (). There are several steps involved in determining this aerodynamic roughness lengthscale, but its procedure typically includes a combination of measurement of wall-shear stress () using direct or indirect methods as well as analysis of velocity profiles. Indirect methods usually rely on assumptions made about flow and its scaling including the validity of universal outer-layer similarity. However, the implications of the underlying assumptions involved in full-scale drag prediction are unclear. In this work, we carry out wind tunnel measurements over a realistic rough surface (from a fouled ship-hull) to evaluate the impact of different methods with an emphasis on using the outer-layer similarity hypothesis for full-scale drag predictions. Wall-shear stress is measured using an in-house floating-element drag balance (DB), and velocity profiles are obtained using particle image velocimetry (PIV), allowing the evaluation of, and the associated wake parameters through several methods. The aerodynamic roughness parameters hence obtained are used for full-scale drag penalty calculations. It is observed that the predicted drag penalty can vary by over 15among the different methods highlighting the care that should be taken when employing such methods.
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影响因子：
2.4
作者：
M. Amir;I. Castro
通讯作者：
M. Amir;I. Castro
影响因子：
3.7
作者：
Womack, Kristofer M.;Meneveau, Charles;Schultz, Michael P.
通讯作者：
Schultz, Michael P.
影响因子：
4.6
作者：
K. Flack;M. Schultz;Jonathan S. Connelly
通讯作者：
K. Flack;M. Schultz;Jonathan S. Connelly
影响因子：
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作者：
A. Perry;J. D. Li
通讯作者：
A. Perry;J. D. Li
影响因子：
3.7
作者：
T. Medjnoun;C. Vanderwel;B. Ganapathisubramani
通讯作者：
T. Medjnoun;C. Vanderwel;B. Ganapathisubramani