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Study of 3-D Dynamic Roughness Effects on Flow Over a NACA 0012 Airfoil Using Large Eddy Simulations at Low Reynolds Numbers.

机译：使用低雷诺数下的大型涡流模拟研究3-D动态粗糙度对流经NACA 0012翼型的影响。

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摘要

There have been several advancements in the aerospace industry in areas of design such as aerodynamics, designs, controls and propulsion; all aimed at one common goal i.e. increasing efficiency --range and scope of operation with lesser fuel consumption. Several methods of flow control have been tried. Some were successful, some failed and many were termed as impractical. The low Reynolds number regime of 104 - 105 is a very interesting range. Flow physics in this range are quite different than those of higher Reynolds number range. Mid and high altitude UAV's, MAV's, sailplanes, jet engine fan blades, inboard helicopter rotor blades and wind turbine rotors are some of the aerodynamic applications that fall in this range. The current study deals with using dynamic roughness as a means of flow control over a NACA 0012 airfoil at low Reynolds numbers. Dynamic 3-D surface roughness elements on an airfoil placed near the leading edge aim at increasing the efficiency by suppressing the effects of leading edge separation like leading edge stall by delaying or totally eliminating flow separation. A numerical study of the above method has been carried out by means of a Large Eddy Simulation, a mathematical model for turbulence in Computational Fluid Dynamics, owing to the highly unsteady nature of the flow. A user defined function has been developed for the 3-D dynamic roughness element motion. Results from simulations have been compared to those from experimental PIV data. Large eddy simulations have relatively well captured the leading edge stall. For the clean cases, i.e. with the DR not actuated, the LES was able to reproduce experimental results in a reasonable fashion. However DR simulation results show that it fails to reattach the flow and suppress flow separation compared to experiments. Several novel techniques of grid design and hump creation are introduced through this study.
机译：航空航天工业在设计领域取得了一些进步，例如空气动力学，设计，控制和推进。所有这些都旨在实现一个共同的目标，即提高效率-减少油耗的运行范围和范围。已经尝试了几种流量控制方法。一些成功，一些失败，许多被认为是不切实际的。 104-105的低雷诺数范围是一个非常有趣的范围。该范围内的流动物理学与雷诺数范围较大的物理学有所不同。中空和高空无人机，无人飞行器，风帆飞机，喷气发动机风扇叶片，舷内直升机旋翼叶片和风力涡轮机旋翼属于该范围内的一些空气动力学应用。当前的研究涉及使用动态粗糙度作为低雷诺数下NACA 0012机翼的流量控制手段。位于前缘附近的机翼上的动态3-D表面粗糙度元素旨在通过延迟或完全消除流分离来抑制前缘分离（如前缘失速）的影响，从而提高效率。由于流动的高度不稳定，已经通过大涡模拟对上述方法进行了数值研究，大涡模拟是计算流体动力学中湍流的数学模型。已经为3D动态粗糙度元素运动开发了用户定义的功能。模拟结果已与实验PIV数据进行了比较。大型涡流模拟已相对较好地捕获了前缘失速。对于干净的情况，即在不启动DR的情况下，LES能够以合理的方式重现实验结果。但是，DR模拟结果表明，与实验相比，它无法重新附着流并抑制流分离。通过这项研究介绍了几种新颖的网格设计和驼峰创建技术。

著录项

  • 作者

    Guda, Venkata Subba Sai Satish.;

  • 作者单位

    West Virginia University.;

  • 授予单位 West Virginia University.;
  • 学科 Mechanical engineering.;Aerospace engineering.
  • 学位 M.S.
  • 年度 2015
  • 页码 90 p.
  • 总页数 90
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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