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An extended wind boundary layer profile

机译：扩展的风边界层剖面

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摘要

Wind over the ocean can be divided into two parts: the mean wind and the unsteady, time-varying wind. The unsteady component of the wind profile is not often included when modeling wind and predicting its impact on ship motions, but may have an effect, particularly in extreme cases. The mean velocity profiles for the wind have been thoroughly investigated and documented, however the time varying portion is not as well understood, mostly due to insufficient data. A portion of the time-varying wind is due to wind gusts, which are typically modeled as a Gaussian stochastic process and can be fully described by a wind gust spectrum [Ocean Engineering 34 (2007), 354-358]. Wind gust spectra measured over land typically have less energy at lower frequencies than measured spectra over the ocean, and this low frequency energy can be important in design of ships and offshore structures. Several wind gust spectra have been proposed, with various dependencies on frequency, height above sea level, and mean wind speed, including Ochi [Proceedings of 20th Offshore Technology Conference, Vol. 2, 1988, pp. 461-467], Wills [Marine Structures 19 (2006), 173-192] and Froya [Marine Structures 19 (2006), 173-192]. These spectra are compared with data collected from the High Resolution Air Sea Interaction (HIRES) research program, sponsored by the Office of Naval Research (ONR), from surface buoy data at 1 m as well as from the R/P FLIP at 30 m above sea level. The various spectra from the literature bound the data at the 1 m level, but all tend to over predict the spectra at the 30 m level. In addition to gusts, the mean wind profile may be modified by the time-varying wave profile, another aspect of wind behavior that can affect the design of ships and offshore structures. Air flow separation over water waves has been observed by many researchers over the years, though a global criterion for separation and a model for the separated flow have not yet been conclusively determined. Evidence in the literature shows that both the wave age and wave slope play a role in separation (for example, in: Proceedings of the ASME 2010 29th International Conference on Ocean, Offshore, and Arctic Engineering, 2010). A separation criterion is proposed, based on data from the literature, as well as a model for the adjusted wind profile based on a separation profile developed for land. The adjusted profile compares well with data from the literature. The criterion and proposed model are also compared with preliminary results from the ONR supported computational fluid dynamics code, Numerical Flow Analysis (NFA). The objective of this numerical effort is to research and develop the capability to couple advanced free-surface hydrodynamic predictions with numerical wind distributions in a marine atmospheric boundary layer. By developing a wind/wave boundary interaction model for the Numerical Flow Analysis (NFA) code, an important step towards carrying out this objective is achieved. It is the final goal of this development to provide a wind/wave interaction prediction capability that includes the possibility of correctly predicting the impact of breaking ambient waves.
机译：海洋上空的风可分为两部分：平均风和不稳定的时变风。在对风进行建模并预测其对船舶运动的影响时，通常不会包括风廓线的非平稳分量，但可能会产生影响，尤其是在极端情况下。已经对风的平均速度分布进行了彻底的调查和记录，但是，由于大部分数据不足，因此对时变部分的了解还不够。一部分随时间变化的风是由于阵风造成的，通常将阵风建模为高斯随机过程，并且可以用阵风谱来全面描述[Ocean Engineering 34（2007），354-358]。通常，在陆地上测得的阵风频谱在较低的频率上具有比在海洋上测得的频谱低的能量，这种低频能量在船舶和海上结构的设计中可能很重要。已经提出了几种阵风谱，其与频率，海拔高度和平均风速有关，包括Ochi [第20届海洋技术会议论文集，第1988年第2卷，第461-467页]，Wills [海洋结构19（2006），第173-192页]和Froya [海洋结构19（2006），第173-192页]。将这些光谱与由海军研究办公室（ONR）赞助的高分辨率空中海洋相互作用（HIRES）研究计划收集的数据，1 m处的表面浮标数据以及30 m处的R / P FLIP数据进行比较海拔以上。来自文献的各种光谱将数据限制在1 m的水平，但是所有这些都倾向于过度预测30 m的光谱。除阵风外，平均风廓线还可以通过随时间变化的波廓线进行修改，这是风行为的另一个方面，会影响船舶和海上结构的设计。多年来，许多研究人员已经观察到水波在气流中的分离，尽管尚未最终确定分离的全球标准和分离流的模型。文献证据表明，波浪年龄和波浪坡度在分离中都起着作用（例如，在：ASME 2010第29届国际海洋，近海和北极工程会议论文集，2010）中。基于文献数据，提出了一种分离标准，并基于针对土地开发的分离剖面，提出了一种用于调整后的风廓线的模型。调整后的配置文件可以很好地与文献数据比较。还将该标准和建议的模型与ONR支持的计算流体动力学代码“数值流分析（NFA）”的初步结果进行了比较。此数值工作的目的是研究和开发将高级自由表面水动力预测与海洋大气边界层中数值风分布耦合的能力。通过为数值流分析（NFA）代码开发风/波边界相互作用模型，朝着实现此目标迈出了重要一步。该开发的最终目标是提供风/波相互作用预测功能，其中包括正确预测破裂环境波的影响的可能性。

著录项

  • 来源
    《International Shipbuilding Progress》 |2013年第4期|495-521|共27页
  • 作者

    A.M. Fullerton; K.L.C. Beale; E. Terrill; D. Dommermuth;

  • 作者单位

    Naval Surface Warfare Center, Carderock Division, West Bethesda, MD, USA;

    Science Applications International Corporation, McLean, VA, USA;

    Scripps Institution of Oceanography, San Diego, CA, USA;

    Science Applications International Corporation, McLean, VA, USA;

  • 收录信息
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    Wind; waves; NFA;

    机译：风;波浪;NFA;

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