TY - JOUR
T1 - Active attenuation of a trailing vortex inspired by a parabolized stability analysis
AU - Edstrand, Adam M.
AU - Sun, Yiyang
AU - Schmid, Peter J.
AU - Taira, Kunihiko
AU - Cattafesta, Louis N.
N1 - Generated from Scopus record by KAUST IRTS on 2022-09-13
PY - 2018/11/25
Y1 - 2018/11/25
N2 - Designing effective control for complex three-dimensional flow fields proves to be non-trivial. Often, intuitive control strategies lead to suboptimal control. To navigate the control space, we use a linear parabolized stability analysis to guide the design of a control scheme for a trailing vortex flow field aft of a NACA0012 half-wing at an angle of attack α = 5° and a chord-based Reynolds number Re = 1000. The stability results show that the unstable mode with the smallest growth rate (fifth wake mode) provides a pathway to excite a vortex instability, whereas the principal unstable mode does not. Inspired by this finding, we perform direct numerical simulations that excite each mode with body forces matching the shape function from the stability analysis. Relative to the uncontrolled case, the controlled flows show increased attenuation of circulation and peak streamwise vorticity, with the fifth-mode-based control set-up outperforming the principal-mode-based set-up. From these results, we conclude that a rudimentary linear stability analysis can provide key insights into the underlying physics and help engineers design effective physics-based flow control strategies.
AB - Designing effective control for complex three-dimensional flow fields proves to be non-trivial. Often, intuitive control strategies lead to suboptimal control. To navigate the control space, we use a linear parabolized stability analysis to guide the design of a control scheme for a trailing vortex flow field aft of a NACA0012 half-wing at an angle of attack α = 5° and a chord-based Reynolds number Re = 1000. The stability results show that the unstable mode with the smallest growth rate (fifth wake mode) provides a pathway to excite a vortex instability, whereas the principal unstable mode does not. Inspired by this finding, we perform direct numerical simulations that excite each mode with body forces matching the shape function from the stability analysis. Relative to the uncontrolled case, the controlled flows show increased attenuation of circulation and peak streamwise vorticity, with the fifth-mode-based control set-up outperforming the principal-mode-based set-up. From these results, we conclude that a rudimentary linear stability analysis can provide key insights into the underlying physics and help engineers design effective physics-based flow control strategies.
UR - https://www.cambridge.org/core/product/identifier/S0022112018007012/type/journal_article
UR - http://www.scopus.com/inward/record.url?scp=85054687003&partnerID=8YFLogxK
U2 - 10.1017/jfm.2018.701
DO - 10.1017/jfm.2018.701
M3 - Article
SN - 1469-7645
VL - 855
JO - Journal of Fluid Mechanics
JF - Journal of Fluid Mechanics
ER -