A time-periodic blowing/suction is provided to control turbulent separation in a boundary layer using direct numerical simulation. The blowing/suction is given just before the separation point, and its nondimensional forcing frequency ranges from F* = fLb/U∞ = 0.28–8.75, where f is the forcing frequency, Lb is the streamwise length of uncontrolled separation bubble, and U∞ is the freestream velocity. The size of separation bubble is minimum at F* = 0.5. At low forcing frequencies of F* ≤ 0.5, vortices generated by the forcing travel downstream at convection velocity of 0.32–0.35 U∞, bring high momentum toward the wall, and reduce the size of separation bubble. However, at high forcing frequencies of F* ≥ 1.56, flow separation disappears and appears in time during the forcing period. This phenomenon occurs due to high wall-pressure gradients alternating favorably and adversely in time. A potential flow theory indicates that this rapid change of the wall pressure in time occurs through an inviscid mechanism. Finally, it is shown that this high-frequency forcing requires a large control input power due to high pressure work.
Skip Nav Destination
Article navigation
October 2016
Research-Article
Control of Flow Separation in a Turbulent Boundary Layer Using Time-Periodic Forcing
Minjeong Cho,
Minjeong Cho
Department of Mechanical and
Aerospace Engineering,
Seoul National University,
1 Gwanak-ro, Gwanak-gu,
Seoul 08826, South Korea
e-mail: minjeongcho1127@gmail.com
Aerospace Engineering,
Seoul National University,
1 Gwanak-ro, Gwanak-gu,
Seoul 08826, South Korea
e-mail: minjeongcho1127@gmail.com
Search for other works by this author on:
Sangho Choi,
Sangho Choi
Department of Mechanical and
Aerospace Engineering,
Seoul National University,
1 Gwanak-ro, Gwanak-gu,
Seoul 08826, South Korea
e-mail: sirius_35@hanmail.net
Aerospace Engineering,
Seoul National University,
1 Gwanak-ro, Gwanak-gu,
Seoul 08826, South Korea
e-mail: sirius_35@hanmail.net
Search for other works by this author on:
Haecheon Choi
Haecheon Choi
Department of Mechanical and
Aerospace Engineering;
Institute of Advanced Machines and Design,
Seoul National University,
1 Gwanak-ro, Gwanak-gu,
Seoul 08826, South Korea
e-mail: choi@snu.ac.kr
Aerospace Engineering;
Institute of Advanced Machines and Design,
Seoul National University,
1 Gwanak-ro, Gwanak-gu,
Seoul 08826, South Korea
e-mail: choi@snu.ac.kr
Search for other works by this author on:
Minjeong Cho
Department of Mechanical and
Aerospace Engineering,
Seoul National University,
1 Gwanak-ro, Gwanak-gu,
Seoul 08826, South Korea
e-mail: minjeongcho1127@gmail.com
Aerospace Engineering,
Seoul National University,
1 Gwanak-ro, Gwanak-gu,
Seoul 08826, South Korea
e-mail: minjeongcho1127@gmail.com
Sangho Choi
Department of Mechanical and
Aerospace Engineering,
Seoul National University,
1 Gwanak-ro, Gwanak-gu,
Seoul 08826, South Korea
e-mail: sirius_35@hanmail.net
Aerospace Engineering,
Seoul National University,
1 Gwanak-ro, Gwanak-gu,
Seoul 08826, South Korea
e-mail: sirius_35@hanmail.net
Haecheon Choi
Department of Mechanical and
Aerospace Engineering;
Institute of Advanced Machines and Design,
Seoul National University,
1 Gwanak-ro, Gwanak-gu,
Seoul 08826, South Korea
e-mail: choi@snu.ac.kr
Aerospace Engineering;
Institute of Advanced Machines and Design,
Seoul National University,
1 Gwanak-ro, Gwanak-gu,
Seoul 08826, South Korea
e-mail: choi@snu.ac.kr
1Corresponding author.
Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received March 7, 2016; final manuscript received June 7, 2016; published online July 29, 2016. Assoc. Editor: D. Keith Walters.
J. Fluids Eng. Oct 2016, 138(10): 101204 (10 pages)
Published Online: July 29, 2016
Article history
Received:
March 7, 2016
Revised:
June 7, 2016
Citation
Cho, M., Choi, S., and Choi, H. (July 29, 2016). "Control of Flow Separation in a Turbulent Boundary Layer Using Time-Periodic Forcing." ASME. J. Fluids Eng. October 2016; 138(10): 101204. https://doi.org/10.1115/1.4033977
Download citation file:
Get Email Alerts
Entrance Lengths for Fully Developed Laminar Flow in Eccentric Annulus
J. Fluids Eng (May 2025)
Switching Events of Wakes Shed From Two Short Flapping Side-by-Side Cylinders
J. Fluids Eng (May 2025)
Related Articles
Separation Control on Low-Pressure Turbine Airfoils Using Synthetic Vortex Generator Jets
J. Turbomach (October,2003)
Large-Eddy Simulation of Unsteady Surface Pressure Over a Low-Pressure Turbine Blade due to Interactions of Passing Wakes and Inflexional Boundary Layer
J. Turbomach (April,2006)
Unsteady Surface Pressures Due to Wake-Induced Transition in a Laminar Separation Bubble on a Low-Pressure Cascade
J. Turbomach (October,2004)
Separated Flow Transition on an LP Turbine Blade With Pulsed Flow Control
J. Turbomach (April,2008)
Related Proceedings Papers
Related Chapters
Cavitating Structures at Inception in Turbulent Shear Flow
Proceedings of the 10th International Symposium on Cavitation (CAV2018)
Introduction
Design and Analysis of Centrifugal Compressors
Extended Surfaces
Thermal Management of Microelectronic Equipment