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Predicting the response of turbulent channel flow to varying-phase opposition control: Resolvent analysis as a tool for flow control design

Toedtli, Simon S. and Luhar, Mitul and McKeon, Beverley J. (2019) Predicting the response of turbulent channel flow to varying-phase opposition control: Resolvent analysis as a tool for flow control design. Physical Review Fluids, 4 (7). Art. No. 073905. ISSN 2469-990X. https://resolver.caltech.edu/CaltechAUTHORS:20190731-130426261

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Abstract

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.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1103/PhysRevFluids.4.073905DOIArticle
https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.4.073905PublisherArticle
ORCID:
AuthorORCID
McKeon, Beverley J.0000-0003-4220-1583
Additional Information:© 2019 American Physical Society. Received 3 November 2018; published 31 July 2019. The authors gratefully acknowledge the U.S. Air Force Office of Scientific Research (Grant No. FA 9550-16-1-0361) for financial support of this work and a graduate fellowship (S.S.T.) from the Resnick Sustainability Institute at Caltech. We would also like to thank J. Jiménez for making his channel DNS code available, P. Koumoutsakos for providing the computational resources for this study, and the reviewers for their feedback, which has greatly improved the quality of this paper.
Group:GALCIT, Resnick Sustainability Institute
Funders:
Funding AgencyGrant Number
Air Force Office of Scientific Research (AFOSR)FA 9550-16-1-0361
Resnick Sustainability InstituteUNSPECIFIED
Issue or Number:7
Record Number:CaltechAUTHORS:20190731-130426261
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20190731-130426261
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97554
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:31 Jul 2019 20:11
Last Modified:03 Oct 2019 21:32

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