[en] The effect of stochastic inflow fluctuations on the jet-switching characteristics of a harmonically plunging elliptic foil at a low Reynolds number regime has been analyzed in the present study. The inflow fluctuations are generated by simulating an Ornstein–Uhlenbeck process—a stationary Gauss–Markov process—with a chosen correlation function. In the absence of fluctuations, quasi-periodic movement of the wake vortices plays a key role in bringing out jet-switching at κh ≥ 1.5. However, fluctuating inflow alters the organized arrangement of the vortex street even at a lower κh (κh = 1.0), giving way to an advanced jet-switching onset. More frequent switching with a larger deflection angle is also observed at κh = 1.5 as compared to the no fluctuation case. Effects of inflow timescales on the deflection angle and switching frequency of the wake are investigated by varying the input correlation-lengths. The underlying flow physics are investigated through a qualitative study of the near-field interactions as well as various quantitative measures derived from the unsteady flow-field.
Disciplines :
Aerospace & aeronautics engineering
Author, co-author :
Majumdar, Dipanjan; Indian Institute of Technology Madras, Chennai 600036, India > Department of Aerospace Engineering
Bose, Chandan ; Université de Liège - ULiège > Département d'aérospatiale et mécanique > Interactions Fluide-Structure - Aérodynamique expérimentale
Sarkar, Sunetra; Indian Institute of Technology Madras, Chennai 600036, India > Department of Aerospace Engineering
Language :
English
Title :
Effect of gusty inflow on the jet-switching characteristics of a plunging foil
Publication date :
12 November 2020
Journal title :
Physics of Fluids
ISSN :
1070-6631
eISSN :
1089-7666
Publisher :
American Institute of Physics, United States - New York
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