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Periodic forcing of a large turbulent separation bubble

Published online by Cambridge University Press:  11 March 2021

Abdelouahab Mohammed-Taifour  and
Julien Weiss Open the ORCID record for Julien Weiss [Opens in a new window]
Abdelouahab Mohammed-Taifour
Affiliation:
Laboratoire de thermo-fluide pour le transport, École de technologie supérieure, Montréal, QuébecH3C 1K3, Canada
Julien Weiss*
Affiliation:
Laboratoire de thermo-fluide pour le transport, École de technologie supérieure, Montréal, QuébecH3C 1K3, Canada Institute of Aeronautics and Astronautics, Technical University of Berlin, 10587Berlin, Germany
*
†Email address for correspondence: [email protected]
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Abstract

The response of a pressure-induced turbulent separation bubble (TSB) to periodic forcing by pulsed-jet actuators (PJAs) positioned in the upstream boundary layer is investigated experimentally in an attempt to elucidate the mechanism of low-frequency contraction and expansion (‘breathing’) already documented in this flow by Mohammed-Taifour & Weiss (J. Fluid Mech., vol. 799, 2016, pp. 383–412). The TSB is generated on a flat test surface by a combination of adverse and favourable pressure gradients and the free-stream velocity is $25\ \textrm {m}\,\textrm {s}^{-1}$. The results indicate that periodic forcing artificially reduces the size of the TSB by moving separation downstream and reattachment upstream. The smaller TSB is associated with narrower streamwise distributions of average pressure and forward-flow fraction, as well as smaller turbulent stresses in the shear layer bounding the recirculation region. Transient forcing experiments further demonstrate that the TSB responds to upstream forcing with a characteristic time scale that is of the same order of magnitude as that of the breathing motion. Overall, the results of this study support a mechanism whereby the low-frequency breathing motion is a response of the TSB to upstream perturbations that affect the position of separation first and, indirectly, the position of reattachment through a global redistribution of the pressure and velocity fields. The low-frequency behaviour of the TSB appears to be well illustrated by a first-order low-pass filter model that converts the broadband fluctuations of the incoming turbulent boundary layer into a low-frequency, large-scale oscillation of the separation and reattachment fronts, thus leading to a contraction and expansion of the TSB. The results of the continuous forcing experiments also offer new insights into active separation control with PJAs by showing that such actuators generate strong starting vortices that, when convected within an adverse pressure gradient, are associated with a downstream shift of the separation front.

JFM classification

Turbulent Flows: Turbulent boundary layers Boundary Layers: Boundary layer separation
Type
JFM Papers
Information
Journal of Fluid Mechanics , Volume 915 , 25 May 2021 , A24
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Copyright
© The Author(s), 2021. Published by Cambridge University Press

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References

REFERENCES

Alam, M. & Sandham, N.D. 2000 Direct numerical simulation of ‘short’ laminar separation bubbles with turbulent reattachment. J. Fluid Mech. 410, 1–28.CrossRefGoogle Scholar
Amitay, M. & Glezer, A. 2002 Role of actuation frequency in controlled flow reattachment over a stalled airfoil. AIAA J. 40 (2), 209–216.CrossRefGoogle Scholar
Babinsky, H. & Harvey, J.K. 2011 Shock Wave-Boundary-Layer Interactions. Cambridge University Press.CrossRefGoogle Scholar
Bendat, J.S. & Piersol, A.G. 2010 Random Data: Analysis and Measurement Procedures, 3rd edn. John Wiley & Sons.CrossRefGoogle Scholar
Bhattacherjee, S., Troutt, T.R. & Scheelke, B. 1986 Modification of vortex interactions in a reattaching separated flow. AIAA J. 24 (4), 623–629.CrossRefGoogle Scholar
Boiko, A.V., Grek, G.R., Dovgal, A.V. & Kozlov, V.V. 2013 The Origin of Turbulence in Near-Wall Flows. Springer Science & Business Media.Google Scholar
Brunn, A. & Nitsche, W. 2003 Separation control by periodic excitation in a turbulent axisymmetric diffuser flow. J. Turbul. 4, N9.CrossRefGoogle Scholar
Brunn, A. & Nitsche, W. 2006 Active control of turbulent separated flows over slanted surfaces. Intl J. Heat Fluid Flow 27 (5), 748–755.CrossRefGoogle Scholar
Camussi, R., Felli, M., Pereira, F., Aloisio, G. & Di Marco, A. 2008 Statistical properties of wall pressure fluctuations over a forward-facing step. Phys. Fluids 20 (7), 075113.CrossRefGoogle Scholar
Cattafesta, L.N. III & Sheplak, M. 2011 Actuators for active flow control. Annu. Rev. Fluid Mech. 43, 247–272.CrossRefGoogle Scholar
Cherry, N.J., Hillier, R. & Latour, M.E.M.P. 1984 Unsteady measurements in a separated and reattaching flow. J. Fluid Mech. 144, 13–46.CrossRefGoogle Scholar
Chun, K.-B. & Sung, H.J. 1996 Control of turbulent separated flow over a backward-facing step by local forcing. Exp. Fluids 21 (6), 417–426.Google Scholar
Clemens, N.T. & Narayanaswamy, V. 2014 Low-frequency unsteadiness of shock wave/turbulent boundary layer interactions. Annu. Rev. Fluid Mech. 46, 469–492.CrossRefGoogle Scholar
Coleman, G.N., Rumsey, C.L. & Spalart, P.R. 2018 Numerical study of turbulent separation bubbles with varying pressure gradient and Reynolds number. J. Fluid Mech. 847, 28–70.CrossRefGoogle ScholarPubMed
D'Adamo, J., Sosa, R. & Artana, G. 2014 Active control of a backward facing step flow with plasma actuators. Trans. ASME: J. Fluids Engng 136 (12).Google Scholar
Dandois, J., Garnier, E. & Sagaut, P. 2007 Numerical simulation of active separation control by a synthetic jet. J. Fluid Mech. 574, 25–58.CrossRefGoogle Scholar
Darabi, A. & Wygnanski, I.J. 2004 a Active management of naturally separated flow over a solid surface. Part 1. The forced reattachment process. J. Fluid Mech. 510, 105–129.CrossRefGoogle Scholar
Darabi, A. & Wygnanski, I.J. 2004 b Active management of naturally separated flow over a solid surface. Part 2. The separation process. J. Fluid Mech. 510, 131–144.CrossRefGoogle Scholar
Dolling, D.S. 2001 Fifty years of shock-wave/boundary-layer interaction research: what next? AIAA J. 39 (8), 1517–1531.CrossRefGoogle Scholar
Dovgal, A.V. & Kozlov, V.V. 1995 On nonlinearity of transitional boundary-layer flows. Phil. Trans. R. Soc. Lond. A 352 (1700), 473–482.Google Scholar
Driver, D.M., Seegmiller, H.L. & Marvin, J.G. 1987 Time-dependent behavior of a reattaching shear layer. AIAA J. 25 (7), 914–919.Google Scholar
Dussauge, J.-P., Dupont, P. & Debiève, J.-F. 2006 Unsteadiness in shock wave boundary layer interactions with separation. Aerosp. Sci. Technol. 10 (2), 85–91.Google Scholar
Eaton, J.K., Jeans, A.H., Ashjaee, J. & Johnston, J.P. 1979 A wall-flow-direction probe for use in separating and reattaching flows. Trans. ASME: J. Fluids Engng 101 (3), 364–366.Google Scholar
Eaton, J.K. & Johnston, J.P. 1982 Low frequency unsteadiness of a reattaching turbulent shear layer. In Turbulent Shear Flows 3, vol. 2, pp. 162–170. Davis.CrossRefGoogle Scholar
Glezer, A. 2011 Some aspects of aerodynamic flow control using synthetic-jet actuation. Phil. Trans. R. Soc. A 369 (1940), 1476–1494.CrossRefGoogle ScholarPubMed
Graftieaux, L., Michard, M. & Grosjean, N. 2001 Combining PIV, POD and vortex identification algorithms for the study of unsteady turbulent swirling flows. Meas. Sci. Technol. 12 (9), 1422.Google Scholar
Graziani, A., Kerhervé, F., Martinuzzi, R.J. & Keirsbulck, L. 2018 Dynamics of the recirculating areas of a forward-facing step. Exp. Fluids 59 (10), 154.CrossRefGoogle Scholar
Greenblatt, D., Whalen, E.A. & Wygnanski, I.J. 2019 Introduction to the flow control virtual collection. AIAA J. 57 (8), 3111–3114.CrossRefGoogle Scholar
Greenblatt, D. & Wygnanski, I.J. 2000 The control of flow separation by periodic excitation. Prog. Aerosp. Sci. 36 (7), 487–545.CrossRefGoogle Scholar
Hain, R., Kähler, C.J. & Radespiel, R. 2009 Dynamics of laminar separation bubbles at low-Reynolds-number aerofoils. J. Fluid Mech. 630, 129–153.Google Scholar
Hecklau, M., Salazar, D.P. & Nitsche, W. 2013 Influence of the actuator jet angle on the reattachment process with pulsed excitation. In New Results in Numerical and Experimental Fluid Mechanics VIII, pp. 143–150. Springer.Google Scholar
Hudy, L.M., Naguib, A.M. & Humphreys, W.M. Jr. 2003 Wall-pressure-array measurements beneath a separating/reattaching flow region. Phys. Fluids 15 (3), 706–717.CrossRefGoogle Scholar
Hussain, A.K.M.F. & Reynolds, W.C. 1970 The mechanics of an organized wave in turbulent shear flow. J. Fluid Mech. 41 (2), 241–258.CrossRefGoogle Scholar
Kiya, M. & Sasaki, K. 1983 Structure of a turbulent separation bubble. J. Fluid Mech. 137, 83–113.CrossRefGoogle Scholar
Kiya, M., Shimizu, M. & Mochizuki, O. 1997 Sinusoidal forcing of a turbulent separation bubble. J. Fluid Mech. 342, 119–139.CrossRefGoogle Scholar
Kotapati, R.B., Mittal, R., Marxen, O., Ham, F., You, D. & Cattafesta, L.N. 2010 Nonlinear dynamics and synthetic-jet-based control of a canonical separated flow. J. Fluid Mech. 654, 65–97.CrossRefGoogle Scholar
Larchevêque, L. 2020 Normalizing low-frequency unsteadiness in compressible separated flows (AIAA 2020-0561). In AIAA SciTech 2020 Forum. AIAA.Google Scholar
LeFloc'h, A., Mohammed-Taifour, A., Dufresne, L. & Weiss, J. 2018 Spanwise aspects of unsteadiness in a pressure-induced turbulent separation bubble (AIAA 2018-3538). In AIAA AVIATION 2018 Forum. AIAA.Google Scholar
LeFloc'h, A., Weiss, J., Mohammed-Taifour, A. & Dufresne, L. 2020 Measurements of pressure and velocity fluctuations in a family of turbulent separation bubbles. J. Fluid Mech. 902, A13.Google Scholar
Ma, X. & Schröder, A. 2017 Analysis of flapping motion of reattaching shear layer behind a two-dimensional backward-facing step. Phys. Fluids 29 (11), 115104.CrossRefGoogle Scholar
Mabey, D.G. 1972 Analysis and correlation of data on pressure fluctuations in separated flows. J. Aircraft 9 (9), 642–645.CrossRefGoogle Scholar
Marxen, O. 2020 Viscous inviscid interaction in laminar separation bubbles (AIAA 2020-1555). In AIAA SciTech 2020 Forum. AIAA.CrossRefGoogle Scholar
Marxen, O. & Henningson, D.S. 2011 The effect of small-amplitude convective disturbances on the size and bursting of a laminar separation bubble. J. Fluid Mech. 671, 1–33.CrossRefGoogle Scholar
Marxen, O. & Rist, U. 2010 Mean flow deformation in a laminar separation bubble: separation and stability characteristics. J. Fluid Mech. 660, 37–54.CrossRefGoogle Scholar
Michelis, T., Yarusevych, S. & Kotsonis, M. 2017 Response of a laminar separation bubble to impulsive forcing. J. Fluid Mech. 820, 633–666.CrossRefGoogle Scholar
Mohammed-Taifour, A. 2017 Instationnarités dans une bulle de décollement turbulente: étude expérimentale. PhD thesis, École de technologie supérieure.Google Scholar
Mohammed-Taifour, A., Dufresne, L. & Weiss, J. 2019 Numerical simulation of a large pressure-induced turbulent separation bubble. In Proceedings of the 27th Canadian Congress of Applied Mechanics, Sherbrooke, Québec, Canada.Google Scholar
Mohammed-Taifour, A., Le Floc'h, A. & Weiss, J. 2020 Active forcing of a pressure-induced turbulent separation bubble (AIAA 2020-1061). In AIAA Scitech 2020 Forum. AIAA.CrossRefGoogle Scholar
Mohammed-Taifour, A., Schwaab, Q., Pioton, J. & Weiss, J. 2015 A new wind tunnel for the study of pressure-induced separating and reattaching flows. Aeronaut. J. 119 (1211), 91–108.CrossRefGoogle Scholar
Mohammed-Taifour, A. & Weiss, J. 2016 Unsteadiness in a large turbulent separation bubble. J. Fluid Mech. 799, 383–412.CrossRefGoogle Scholar
Pasquariello, V., Hickel, S. & Adams, N.A. 2017 Unsteady effects of strong shock-wave/boundary-layer interaction at high Reynolds number. J. Fluid Mech. 823, 617–657.CrossRefGoogle Scholar
Petz, R. & Nitsche, W. 2007 Active separation control on the flap of a two-dimensional generic high-lift configuration. J. Aircraft 44 (3), 865–874.CrossRefGoogle Scholar
Piponniau, S., Dussauge, J.-P., Debiève, J.F. & Dupont, P. 2009 A simple model for low-frequency unsteadiness in shock-induced separation. J. Fluid Mech. 629, 87–108.CrossRefGoogle Scholar
Plotkin, K.J. 1975 Shock wave oscillation driven by turbulent boundary-layer fluctuations. AIAA J. 13 (8), 1036–1040.CrossRefGoogle Scholar
Poggie, J., Bisek, N.J., Kimmel, R.L. & Stanfield, S.A. 2015 Spectral characteristics of separation shock unsteadiness. AIAA J. 53 (1), 200–214.CrossRefGoogle Scholar
Porter, K.M. & Poggie, J. 2019 Selective upstream influence on the unsteadiness of a separated turbulent compression ramp flow. Phys. Fluids 31 (1), 016104.CrossRefGoogle Scholar
Priebe, S., Tu, J.H., Rowley, C.W. & Martín, M.P. 2016 Low-frequency dynamics in a shock-induced separated flow. J. Fluid Mech. 807, 441–477.CrossRefGoogle Scholar
Schwaab, Q. & Weiss, J. 2015 Evaluation of a thermal-tuft probe for turbulent separating and reattaching flows. Trans. ASME: J. Fluids Engng 137, 011401.Google Scholar
Sigurdson, L.W. 1995 The structure and control of a turbulent reattaching flow. J. Fluid Mech. 298, 139–165.CrossRefGoogle Scholar
Simpson, R.L. 1989 Turbulent boundary-layer separation. Annu. Rev. Fluid Mech. 21, 205–234.CrossRefGoogle Scholar
Spalart, P.R. & Strelets, M.K. 2000 Mechanisms of transition and heat transfer in a separation bubble. J. Fluid Mech. 403, 329–349.CrossRefGoogle Scholar
Steinfurth, B. & Weiss, J. 2020 Vortex rings produced by non-parallel planar starting jets. J. Fluid Mech. 903, A16.CrossRefGoogle Scholar
Threadgill, J.A.S. & Bruce, P.J.K. 2020 Unsteady flow features across different shock/boundary-layer interaction configurations. AIAA J. 58 (7), 1–13.CrossRefGoogle Scholar
Touber, E. & Sandham, N. 2011 Low-order stochastic modelling of low-frequency motions in reflected shock-wave/boundary-layer interactions. J. Fluid Mech. 671, 417–465.CrossRefGoogle Scholar
Weiss, J., Little, J., Threadgill, J. & Gross, A. 2021 Low-frequency unsteadiness in pressure-induced separation bubbles (AIAA 2021-1324). In AIAA SciTech 2021 Forum. AIAA.CrossRefGoogle Scholar
Weiss, J., Mohammed-Taifour, A. & Schwaab, Q. 2015 Unsteady behavior of a pressure-induced turbulent separation bubble. AIAA J. 53 (9), 2634–2645.CrossRefGoogle Scholar
Weiss, J., Schwaab, Q., Boucetta, Y., Giani, A., Guigue, C., Combette, P. & Charlot, B. 2017 Simulation and testing of a MEMS calorimetric shear-stress sensor. Sensors Actuators A 253, 210–217.CrossRefGoogle Scholar
Wu, W., Meneveau, C. & Mittal, R. 2020 Spatio-temporal dynamics of turbulent separation bubbles. J. Fluid Mech. 883, A45.CrossRefGoogle Scholar
Yarusevych, S. & Kotsonis, M. 2017 Steady and transient response of a laminar separation bubble to controlled disturbances. J. Fluid Mech. 813, 955–990.CrossRefGoogle Scholar

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