Abstract
The coupling between a pitching axisymmetric bluff body and its wake is modified in wind tunnel experiments using controlled interactions between fluidic actuators and the cross-flow over its aft end. The model trajectory is controlled using eight servo-controlled support wires with inline force transducers that are operated in closed loop with feedback from a motion analysis system which effects control authority of the wind tunnel model in all six degrees of freedom. The model dynamics studied in the present work is constrained to pitch. Actuation is effected by two integrated aft-facing synthetic jet actuators in the plane of the body pitch oscillation such that each actuator effects a time-dependent segment of local flow attachment over the aft surface. The present investigation focuses on the reciprocal relation between the response of the near and far wake to the actuation and the associated changes in the induced aerodynamic loads when the body executes nearly time-harmonic pitch over a range of reduced oscillation frequencies (up to k = 0.26) for ReD up to 2.3 × 105. The response of the wake to stabilizing and destabilizing actuations that effect reduction or enhancement of the aerodynamic loads is investigated using particle image velocimetry (PIV) and hotwire anemometry in the near and far wake, respectively. It is shown that the studied flow control approach induces aerodynamic loads that are comparable to the loads on the base flow pitching motions and therefore may be suitable for in-flight stabilization.
Graphic Abstract
The global unsteady aerodynamic loads on a pitching axisymmetric bluff body are controlled by modification of the coupling between the flow over body and its near wake using two synthetic jet actuators in the plane of motion on the body’s aft end. This actuation results in a time-dependent partial flow attachment of the nominally axisymmetric separating shear layer of the base flow over the aft end of the body, and the asymmetric changes have a profound effect on the evolution of the wake. These changes in the wake dynamics feed back to alter the global aerodynamic forces and moments, leading to about a 50% increase or decrease in the dynamic lift force or pitching moment, depending on the flow control strategy.
Similar content being viewed by others
References
Abramson P, Vukasinovic B, Glezer A (2011) Direct measurements of controlled aerodynamic forces on a wire-suspended axisymmetric body. Exp Fluids 50(6):1711–1725
Abramson P, Vukasinovic B, Glezer A (2012) Fluidic control of aerodynamic forces on a bluff body of revolution. AIAA J 50(4):832–843
Corke TC, Tillotson D, Patel MP, Su WJ, Toledo W (2008) Radius flow vectoring for projectile drag and steering control using plasma actuators. AIAA Paper 2008-3769
Freund JB, Mungal MG (1994) Drag and wake modification of axisymmetric bluff bodies using Coanda blowing. J Aircr 31(3):572–578
Hoerner SF (1965) Fluid-dynamic drag. In: Hoerner Fluid Dynamics. Bricktown, NJ
Jardin T, Bury Y (2014) Distributed forcing of the flow past a blunt-based axisymmetric bluff body. Theor Comput Fluid Dyn 28(3):259–266
Lācis U, Brosse N, Ingremeau F, Mazzino A, Lundell F, Kellay H, Bagheri S (2014) Passive appendages generate drift through symmetry breaking. Nat Commun 5:5310
Lambert TJ, Vukasinovic B, Glezer A (2015) Active decoupling of the axisymmetric body wake response to a pitching motion. J Fluid Struct 59:129–145
Lambert TJ, Vukasinovic B, Glezer A (2016) A six degrees of freedom dynamic wire-driven traverse. Aerospace 3:11
Lambert TJ, Vukasinovic B, Glezer A (2019) A freely yawing axisymmetric bluff body controlled by near-wake flow coupling. J Fluid Mech 863:1123–1156
Meliga P, Sipp D, Chomaz J-M (2010) Open-loop control of compressible afterbody flows using adjoint methods. Phys Fluids 22(5):054109
Monkewitz PA (1988) A note on vortex shedding from axisymmetric bluff bodies. J Fluid Mech 192:561–575
Oxlade AR, Morrison JF, Qubain A, Rigas G (2015) High-frequency forcing of a turbulent axisymmetric wake. J Fluid Mech 770:305–318
Rigas G, Oxlade AR, Morgans AS, Morrison JF (2014) Low-dimensional dynamics of a turbulent axisymmetric wake. J Fluid Mech 755:R5
Rinehart C, McMichael JM, Glezer A (2003) Transitory flow and force development on a body of revolution using synthetic jet actuation. AIAA Paper 2003-0618
Sevilla A, Martínez-Bazán C (2004) Vortex shedding in high Reynolds number axisymmetric bluff-body wakes: local linear instability and global bleed control. Phys Fluids 16(9):3460–3469
Wilson J, Schatzman D, Arad E, Seifert A, Shtendel T (2013) Suction and pulsed-blowing flow control applied to an axisymmetric body. AIAA J 51(10):2432–2446
Yeo LY, Friend JR (2014) Surface acoustic wave microfluidics. Annu Rev Fluid Mech 46:379–406
Acknowledgements
This work was supported by the Army Research Office monitored by Dr. M. Munson (Grant No. W911NF-15-1-0153).
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Lambert, T.J., Vukasinovic, B. & Glezer, A. Controlled axisymmetric body-wake coupling in a pitching motion. Exp Fluids 61, 109 (2020). https://doi.org/10.1007/s00348-020-02944-4
Received:
Revised:
Accepted:
Published:
DOI: https://doi.org/10.1007/s00348-020-02944-4