TY - JOUR
T1 - Flow-induced motions of flexible plates
T2 - Fluttering, twisting and orbital modes
AU - Jin, Yaqing
AU - Kim, Jin Tae
AU - Fu, Shifeng
AU - Chamorro, Leonardo P.
N1 - This work was supported by the Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, as part of the start-up package of L.P.C.
PY - 2019/4/10
Y1 - 2019/4/10
N2 - The unsteady dynamics of wall-mounted flexible plates under inclined flows was fundamentally described using theoretical arguments and experiments under various Cauchy numbers (where is the fluid density, and are the plate width and length, is the incoming velocity, is Young's modulus and is the second moment of the area) and inclination angles . Three-dimensional particle tracking velocimetry and a high-resolution force sensor were used to characterize the evolution of the plate dynamics and aerodynamic force. We show the existence of three distinctive, dominant modes of tip oscillations, which are modulated by the structure dynamic and flow instability. The first mode is characterized by small-amplitude, planar fluttering-like motions occurring under a critical Cauchy number, . Past this condition, the motions are dominated by the second mode consisting of unsteady twisting superimposed onto the fluttering patterns. The onset of this mode is characterized by a sharp increase of the force fluctuation intensity. At sufficiently high and , the plate may undergo a third mode given by large-scale tip orbits about the mean bending. Using the equation of motion and first-order approximations, we propose a formulation to estimate as a function of ; it exhibits solid agreement with experiments.
AB - The unsteady dynamics of wall-mounted flexible plates under inclined flows was fundamentally described using theoretical arguments and experiments under various Cauchy numbers (where is the fluid density, and are the plate width and length, is the incoming velocity, is Young's modulus and is the second moment of the area) and inclination angles . Three-dimensional particle tracking velocimetry and a high-resolution force sensor were used to characterize the evolution of the plate dynamics and aerodynamic force. We show the existence of three distinctive, dominant modes of tip oscillations, which are modulated by the structure dynamic and flow instability. The first mode is characterized by small-amplitude, planar fluttering-like motions occurring under a critical Cauchy number, . Past this condition, the motions are dominated by the second mode consisting of unsteady twisting superimposed onto the fluttering patterns. The onset of this mode is characterized by a sharp increase of the force fluctuation intensity. At sufficiently high and , the plate may undergo a third mode given by large-scale tip orbits about the mean bending. Using the equation of motion and first-order approximations, we propose a formulation to estimate as a function of ; it exhibits solid agreement with experiments.
KW - Flow-structure interactions
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U2 - 10.1017/jfm.2019.40
DO - 10.1017/jfm.2019.40
M3 - Article
AN - SCOPUS:85061186222
SN - 0022-1120
VL - 864
SP - 273
EP - 285
JO - Journal of Fluid Mechanics
JF - Journal of Fluid Mechanics
ER -