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Evolutional Fundamental Study on Active Control of Wall Turbulence

壁面湍流主动控制的演化基础研究

基本信息

批准号：
20246036
负责人：
KASAGI Nobuhide
金额：
$ 31.78万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2008
资助国家：
日本
起止时间：
2008 至 2010
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-20246036/
关键词：
乱流流体制御能動制御数値シミュレーション MEMS

项目摘要

Facing the global issues such as depletion of energy resources and environmental deterioration, highly advanced technology of turbulence control is ever more needed. Turbulence control opens up new possibilities to achieve far greater efficiency and least environmental impact of various thermal-fluid systems supporting the human society through the manipulation and modification of momentum/heat/mass transfer, noise as well as chemical reaction. In the present study, we focused on one of the most canonical flows, i.e., wall turbulence and associated transport phenomena. We particularly aimed at developing innovative predetermined controls to drastically reduce skin friction drag and enhance heat/mass transfer. Specifically, we introduced new control indices such as the net energy saving rate and the control gain in order to evaluate cost effectiveness of existing control strategies and also a newly proposed traveling wave-like wall blowing/suction. We also applied uniform blowing/suction to a turbulent boundary layer to obtain general control strategies for spatially developing flows. For heat/mass transfer enhancement, we reexamined the governing equations and boundary conditions for the velocity and scalar fields in order to clarify possible scenarios for dissimilar heat transfer enhancement control. By applying the optimal control theory, we demonstrated that the dissimilar control is possible with a simple open-loop control strategy.

面对能源枯竭、环境恶化等全球性问题，对湍流控制技术的需求越来越高。湍流控制开辟了新的可能性，以实现更高的效率和最小的环境影响的各种热流体系统支持人类社会通过操纵和修改的动量/热量/质量传递，噪音以及化学反应。在本研究中，我们专注于最规范的流之一，即，壁湍流和相关的传输现象。我们特别致力于开发创新的预定控制，以大幅降低表面摩擦阻力并增强热/质传递。具体而言，我们引入了新的控制指标，如净节能率和控制增益，以评估现有的控制策略的成本效益，也是一个新提出的行波式壁吹/吸。我们还应用均匀吹/吸湍流边界层，以获得空间发展流动的一般控制策略。对于传热/传质增强，我们重新检查了速度和标量场的控制方程和边界条件，以澄清不同的传热增强控制的可能方案。通过应用最优控制理论，我们证明了用简单的开环控制策略实现不同控制是可能的。