Active control of large-scales in a high-Reynolds-number turbulent boundary layer

Ruan, Z, Baars, W, Abbassi, M, Hutchins, N and Marusic, I 2018, 'Active control of large-scales in a high-Reynolds-number turbulent boundary layer', in T.C.W. Lau and R.M. Kelso (ed.) Proceeding of the 21st Australasian Fluid Mechanics Conference (AFMC 2018), Adelaide, Australia, 10-13 December 2018, pp. 1-4.


Document type: Conference Paper
Collection: Conference Papers

Title Active control of large-scales in a high-Reynolds-number turbulent boundary layer
Author(s) Ruan, Z
Baars, W
Abbassi, M
Hutchins, N
Marusic, I
Year 2018
Conference name AFMC 2018
Conference location Adelaide, Australia
Conference dates 10-13 December 2018
Proceedings title Proceeding of the 21st Australasian Fluid Mechanics Conference (AFMC 2018)
Editor(s) T.C.W. Lau and R.M. Kelso
Publisher Australasian Fluid Mechanics Society
Place of publication Western Australia, Australia
Start page 1
End page 4
Total pages 4
Abstract The relationship between large-scale structures and near-wall turbulence in both canonical and perturbed high Reynolds number turbulent boundary layers (Reτ = 14400, U∞ = 20 m/s) is investigated experimentally. A spanwise array of hot-film probes and wall-normal jets are placed 1.7δ apart in the streamwise direction to observe, and selectively perturb, large-scale events in the logarithmic region with the implementation of different control strategies. Using a further spanwise array of hot-films and a traversing hot-wire probe downstream of the actuators, we evaluate the influence of the modified large-scale structures on the wall-shear stress fluctuations. In terms of flow control, it is anticipated that the maximum skin-friction reduction with the current control infrastructure is bounded at 4.5%. Owing to the imperfection of the actuation process, this value fails to match the potential 8% mean-wall-shear-stress contributed by the large-scale motions and very large-scale motions with streamwise wavelength greater than 1.5δ in the turbulent boundary layer at Reτ = 14400, which is extrapolated based on the relationship between the large-scale turbulence energy variation for each perturbed boundary layer and their corresponding skinfriction drag change.
Subjects Aerodynamics (excl. Hypersonic Aerodynamics)
ISBN 9780646597843
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