Imperial College London
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DrAndrewWynn

Faculty of Engineering, Department of Aeronautics

Reader in Control and Optimization
 
 
 
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Contact

 

+44 (0)20 7594 5047a.wynn Website

 
 
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Location

 

340City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Mahfoze:2019,
author = {Mahfoze, O and Moody, A and Wynn, A and Whalley, R and Laizet, S},
journal = {Physical Review Fluids},
pages = {094601--1--094601--23},
title = {Reducing the skin-friction drag of a turbulent boundary-layer flow with low-amplitude wall-normal blowing within a Bayesian optimisation framework},
url = {https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.4.094601},
volume = {4},
year = {2019}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - A Bayesian optimisation framework is developed to optimise low-amplitude wall-normal blowing control of a turbulent boundary-layer flow. The Bayesian optimisation framework determines the optimum blowing amplitude and blowing coverage to achieve up to a 5% net-power saving solution within 20 optimisation iterations, requiring 20 Direct Numerical Simulations (DNS). The power input required to generate the low-amplitude wall-normal blowing is measured experimentally for two different types of blowing device, and is used in the simulations to assess control performance. Wall-normal blowing with amplitudes of less than 1% of the free-stream velocity generate a skin-friction drag reduction of up to 76% over the control region, with a drag reduction which persists for up to 650δ0 downstream of actuation (where δ0 is the boundary-layer thickness at the start of the simulation domain). It is shown that it is the slow spatial recovery of the turbulent boundary-layer flow downstream of control which generates the net-power savings in this study. The downstream recovery of the skin-friction drag force is decomposed using the Fukagata-Iwamoto-Kasagi (FIK) identity, which shows that the generation of the net-power savings is due to changes in contributions to both the convection and streamwise development terms of the turbulent boundary-layer flow.
AU  - Mahfoze,O
AU  - Moody,A
AU  - Wynn,A
AU  - Whalley,R
AU  - Laizet,S
EP  - 1
PY  - 2019///
SN  - 2469-990X
SP  - 094601
TI  - Reducing the skin-friction drag of a turbulent boundary-layer flow with low-amplitude wall-normal blowing within a Bayesian optimisation framework
T2  - Physical Review Fluids
UR  - https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.4.094601
UR  - http://hdl.handle.net/10044/1/73016
VL  - 4
ER  -
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