Chaoqun LI, Shuo TANG, Yi LI, et al. Sub⁃optimization of riblet shape based on neural networks[J]. Journal of Aerospace Power, 2022, 37(3): 639-648.
DOI:
Chaoqun LI, Shuo TANG, Yi LI, et al. Sub⁃optimization of riblet shape based on neural networks[J]. Journal of Aerospace Power, 2022, 37(3): 639-648.DOI: 10.13224/j.cnki.jasp.20210683.
Sub⁃optimization of riblet shape based on neural networks
For the riblet drag reduction,a neural network⁃based method was used to optimize the shape of the riblet surface.This work employed the channel flow model and the governing equations were the viscous incompressible Navier⁃Stokes (NS) equations.The turbulent flow inside the channel was resolved by the direct numerical simulation (DNS) method.According to the numerical method,a compact fourth⁃order central scheme was used for the discretization of the convective term,a fourth⁃order central scheme was applied to the discretization of the viscous term,and a third⁃order Runge⁃Kutta scheme was employed for the time advancement.In the neural network sub⁃optimization process,the constraint equation was the incompressible NS equation,and an adaptive controller based on online learning was used.In the optimization procedure,the control law was based on weakening the spanwise shear stress,and the control quantities were provided by the wall deformation.The optimization results demonstrated that the maximum wall drag reduction reached 17.41%.For the wall optimization,the turbulence intensity was reduced by 19.68%,besides,the vorticity and Reynolds shear stress at the wall also declined.Since the turbulent flow was unsteady,the shape of the optimized wall also varied with time,but the overall shape of the riblets still illustrated a streamwise riblet⁃like configuration.
HU Haibao , SONG Baowei , LIU Zhanyi , et al . Research about the characteristic of drag reduction over riblets surface based on average velocity profile in the turbulent boundary layer [J]. Journal of Aerospace Power , 2009 , 24 ( 5 ): 1040 ⁃ 1047 . (in Chinese)
WALSH M J . Riblets as a viscous drag reduction technique [J]. AIAA Journal , 1983 , 21 ( 4 ): 485 ⁃ 486 .
WALSH M J . Effect of detailed surface geometry on riblet drag reduction performance [J]. Journal of Aircraft , 1990 , 27 ( 6 ): 572 ⁃ 573 .
LUCHINI P , MANZO F , POZZI A . Resistance of a grooved surface to parallel flow and cross⁃flow [J]. Journal of Fluid Mechanics , 1991 , 228 : 87 ⁃ 109 .
CHANG Yuefeng , JIANG Nan . Experimental study on coherent structure passive control and drag reduction in turbulent boundary layer with grooved surface [J]. Journal of Aerospace Power , 2008 , 23 ( 5 ): 788 ⁃ 795 . (in Chinese)
WANG Jinjun , CHEN Guang . Experimental studies on the near wall turbulent coherent structures over riblets surfaces [J]. Acta Aeronautica et Astronautica Sinica , 2001 , 22 ( 5 ): 400 ⁃ 405 . (in Chinese)
CUI G Y , PAN C , WU D , et al . Effect of drag reducing riblet surface on coherent structure in turbulent boundary layer [J]. Chinese Journal of Aeronautics , 2019 , 32 ( 11 ): 2433 ⁃ 2442 .
WANG Erdan , TIAN Haiping , ZHANG Jingxian , et al . TRPIV experimental investigation of drag⁃reduction mechanism in turbulent boundary layer over super hydrophobic surfaces [J]. Journal of Aerospace Power , 2016 , 31 ( 12 ): 2870 ⁃ 2877 . (in Chinese)
SUNDARAM S , VISWANATH P R , RUDRAKUMAR S . Viscous drag reduction using riblets on a NACA 0012 airfoil to moderate incidence [J]. AIAA Journal , 1996 , 34 ( 4 ): 676 ‑ 682 .
SUBASHCHANDAR N , RAJEEV K , SUNDARAM S . Drag reduction due to riblets on a GAW(2) airfoil [J]. Jornal of Aircraft , 1999 , 36 ( 5 ): 890 ⁃ 892 .
ZHANG Y F , CHEN H X , FU S , et al . Numerical study of an airfoil with riblets installed based on large eddy simulation [J]. Aerospace Since and Technology , 2018 , 78 : 661 ⁃ 670 .
ZHANG Ziliang , ZHANG Mingming . Aerodynamic performance for bionic drag⁃reducing airfoil [J]. Journal of Aerospace Power , 2021 , 36 ( 8 ): 1740 ⁃ 1748 . (in Chinese)
JIMÉNEZ J , MOIN P . The minimal flow unit in near⁃wall turbulence [J]. Journal of Fluid Mechanics , 1991 , 225 : 213 ⁃ 240 .
CARLSON H , LUMLEY J . Active control in the turbulent wall layer of a minimal flow unit [J]. Journal of Fluid Mechanics , 1996 , 329 : 341 ⁃ 371 .
KIM J , MOIN P . Application of a fractional⁃step method to incompressible Navier⁃Stokes equations [J]. Journal of Computational Physics , 1985 , 59 ( 2 ): 308 ⁃ 323 .
CHOI H , MOIN P , KIM J . Direct numerical simulation of turbulent over riblets [J]. Journal of Fluid Mechanics , 1993 , 255 : 503 ⁃ 539 .
CHU C D , KARNIADAKIS E G . A direct numerical simulation of laminar and turbulent flow over riblet⁃mounted surfaces [J]. Journal of Fluid Mechanics , 1993 , 250 : 1 ⁃ 42 .
GOLDSTEIN D , HANDLER R , SIROVICH L . Direct numerical simulation of turbulent flow over a modeled riblet covered surface [J]. Journal of Fluid Mechanics , 1995 , 302 : 333 ⁃ 376 .
CHOI H , MOIN P , KIM J . Active turbulence control for drag reduction in wall⁃bounded flows [J]. Journal of Fluid Mechanics , 1994 , 262 : 75 ⁃ 110 .
ENDO T , KASAGI N , SUZUKI Y . Feedback control of wall turbulence with wall deformation [J]. International Journal of Heat and Fluid Flow , 2000 , 21 ( 5 ): 568 ⁃ 575 .
KANG S , CHOI H . Active wall motions for skin⁃friction drag reduction [J]. Physics of Fluids , 2000 , 12 ( 12 ): 3301 ⁃ 3304 .
LEE C , KIM J , BABCOCK D , et al . Application of neural networks to turbulence control for drag reduction [J]. Physics of Fluids , 1997 , 9 ( 6 ): 1740 ⁃ 1747 .
HAN Bingzheng , HUANG Weixi . Active control for drag reduction of turbulent channel flow based on convolutional neural networks [J]. Physics of Fluids , 2020 , 32 ( 9 ): 095108.1 ⁃ 095108.13 .
RABAULT J , KUCHTA M , JENSEN A , et al . Artificial neural networks trained through deep reinforcement learning discover control strategies for active flow control [J]. Journal of Fluid Mechanics , 2019 , 865 : 281 ⁃ 302 .
VIQUERAT J , RABAULT J , KUHNLE A , et al . Direct shape optimization through deep reinforcement learning [J]. Journal of Computational Physics , 2021 , 428 : 110080.1 ⁃ 110080.12 .
LELE S K . Compact finite difference schemes with spectral⁃like resolution [J]. Journal of Computational Physics , 1992 , 103 ( 1 ): 16 ⁃ 42 .
SHAH A , FAYYAZ H , RIZWAN M . Fourth⁃order central compact scheme for the numerical solution of incompressible Navier⁃Stokes equations [J]. International Journal of Computer Mathematics , 2017 , 94 ( 12 ): 2492 ⁃ 2507 .
LORANG LV , PODVIN B , Le QUÉRÉ P . Application of compact neural network for drag reduction in a turbulent channel flow at low Reynolds numbers [J]. Physics of Fluids , 2008 , 20 ( 4 ): 045104.1 ⁃ 045104.13 .
POPE S B . Turbulent flows [M]. Cambridge : Cambridge University Press , 2000 .