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DNS-BASED ADJOINT OPTIMIZATION OF THE WALL SHAPE IN TURBULENT CHANNEL FLOW

Köthe, Thomas and Wagner, Claus (2017) DNS-BASED ADJOINT OPTIMIZATION OF THE WALL SHAPE IN TURBULENT CHANNEL FLOW. 16th European Turbulence Conference (ETC16), 21.-24. Aug. 2017, Stockholm, Schweden.

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Official URL: http://www.etc16.se/

Abstract

Direct Numerical Simulations (DNS) of turbulent channel flow are performed in a computaional domain and for the friction Reynolds number Reτ = 180 realized by Kim with the aim to reduce the skin friction by controlling the near- wall transport processes based on surface modifications. The latter are determined by solving the adjoint Navier-Stokes equations which depend on time-averaged DNS flow fields. It is well known that the wall-normal momentum Transport is organized in sweep and ejection events in the boundary layer which controls skin friction. Bewley et al. used adjoint optimization for suction and blowing in turbulent channel flow. They mitigated the effect of the wall-normal transport by opposing near-wall vertical motions of the fluid with an equal and opposite control velocity at the wall. The aim of this work is to achieve this with wall surface modifications. The idea is further to damp the spanwise fluctuations of streaky structures and thus, to reduce the associated skin friction.

Item URL in elib:https://elib.dlr.de/110964/
Document Type:Conference or Workshop Item (Speech)
Title:DNS-BASED ADJOINT OPTIMIZATION OF THE WALL SHAPE IN TURBULENT CHANNEL FLOW
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Köthe, Thomasthomas.koethe (at) dlr.deUNSPECIFIED
Wagner, ClausClaus.Wagner (at) dlr.deUNSPECIFIED
Date:2017
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:adjoint shape optimization, passive flow control, coherent structures
Event Title:16th European Turbulence Conference (ETC16)
Event Location:Stockholm, Schweden
Event Type:international Conference
Event Dates:21.-24. Aug. 2017
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Transport
HGF - Program Themes:Terrestrial Vehicles (old)
DLR - Research area:Transport
DLR - Program:V BF - Bodengebundene Fahrzeuge
DLR - Research theme (Project):V - Next Generation Train III (old)
Location: Göttingen
Institutes and Institutions:Institute for Aerodynamics and Flow Technology > Fluid Systems, GO
Deposited By: Bachmann, Barbara
Deposited On:27 Nov 2017 15:41
Last Modified:31 Jul 2019 20:08

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