Predicting the response of turbulent channel flow to varying-phase opposition control: Resolvent analysis as a tool for flow control design
Predicting the response of turbulent channel flow to varying-phase opposition control: Resolvent analysis as a tool for flow control design
复制标题
预测湍流通道流对变相反对控制的响应：溶解分析作为流量控制设计的工具
DOI：
10.1103/physrevfluids.4.073905
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发表时间：
2019
影响因子：
2.7
通讯作者：
B. McKeon
中科院分区：
文献类型：
--
作者：
Simon S. Toedtli;M. Luhar;B. McKeon
本研究基于McKeon和Sharma [B. McKeon和A. S. Sharma，J.Fluid Mech.658，336（2010）]，用于壁边界湍流中的减阻的控制器设计。为此，我们首先表明，该模型是能够近似的平均壁面剪应力，这是常用的减阻措施的变化。我们还推导出一个解析表达式，分解的内部流的减阻到条款，可以直接预测的模型和条款，允许量化的模型误差，如果高保真数据可用。然后，我们通过在低雷诺数湍流槽道流中的变相反向控制的示例表明，由预解式模型预测的减阻捕获了在宽范围的控制器参数上在直接数值模拟（DNS）中观察到的趋势。DNS结果证实了预解模型预测，可达到的减阻强烈依赖于传感器测量和致动器响应之间的相对相位，这为未来的研究提出了有趣的流动物理问题。的预解模型和DNS之间的良好协议进一步表明，预解分析，这在其心脏是一个线性技术，是能够近似的全非线性系统的控制响应。我们还表明，为了作出准确的预测，该模型只需要解决一个小的DNS波数的子集和控制的预解模式服从的不受控制的预解算子由Moarref等导出的Molds数标度律。Moarref等人，J. Fluid Mech.734，275（2013）]。因此，我们的研究结果表明，预解式分析可以提供一个合适的流动模型，设计反馈流控制方案的目的，在不可压缩的壁有界湍流的阻力减少，即使在技术相关的雷诺数。
The present study evaluates the capabilities of a low-order flow model based on the resolvent analysis of McKeon and Sharma [B. J. McKeon and A. S. Sharma, J. Fluid Mech. 658, 336 (2010)] for the purpose of controller design for drag reduction in wall-bounded turbulent flows. To this end, we first show that the model is able to approximate the change in mean wall shear stress, which is commonly used as measure for drag reduction. We also derive an analytical expression that decomposes the drag reduction in internal flows into terms that can be predicted directly by the model and terms that allow for quantification of model error if high-fidelity data are available. We then show by example of varying-phase opposition control in a low-Reynolds-number turbulent channel flow that the drag reduction predicted by the resolvent model captures the trend observed in direct numerical simulation (DNS) over a wide range of controller parameters. The DNS results confirm the resolvent model prediction that the attainable drag reduction strongly depends on the relative phase between sensor measurement and actuator response, which raises interesting flow physics questions for future studies. The good agreement between the resolvent model and DNS further reveals that resolvent analysis, which at its heart is a linear technique, is able to approximate the response of the full nonlinear system to control. We also show that in order to make accurate predictions the model only needs to resolve a small subset of the DNS wave numbers and that the controlled resolvent modes obey the Reynolds-number scaling laws of the uncontrolled resolvent operator derived by Moarref et al. [R. Moarref et al., J. Fluid Mech. 734, 275 (2013)]. As a consequence, our results suggest that resolvent analysis can provide a suitable flow model to design feedback flow control schemes for the purpose of drag reduction in incompressible wall-bounded turbulent flows even at technologically relevant Reynolds numbers.
影响因子：
3.7
作者：
McKeon, B. J.;Sharma, A. S.
通讯作者：
Sharma, A. S.