TY - JOUR
T1 - Material and geometric effects on propulsion of a fish tail
AU - Hussein, Ahmed A.
AU - Ragab, Saad A.
AU - Hajj, Muhammad R.
AU - Patil, Mayuresh J.
N1 - Publisher Copyright:
© 2021 IOP Publishing Ltd.
PY - 2021/11
Y1 - 2021/11
N2 - We investigate the effects of material flexibility and aspect ratio on the propulsion of flapping tails. The tail, which is assumed to deform in the bending direction only, is modeled using the Euler-Bernoulli beam theory. The hydrodynamic loads generated by the flapping motion are calculated using the three-dimensional unsteady vortex lattice method. The finite element method is used to solve the coupled time-dependent equations of motion using an implicit solver for time integration. The results show improvement in the thrust and propulsive efficiency over a specific range of non-dimensional flexibility defined by the ratio of the elastic forces to fluid pressure forces. Structural and flow characteristics associated with the improved performance are discussed. As for geometric effects, the performance depends on the excitation frequency. At low frequencies, the improvement is continuous with increasing the aspect ratio in a manner similar to that of rigid tails. At higher frequencies, the improvement is limited to a region defined by aspect ratios that are less than 0.5. The extent of the improvement depends on the flexibility.
AB - We investigate the effects of material flexibility and aspect ratio on the propulsion of flapping tails. The tail, which is assumed to deform in the bending direction only, is modeled using the Euler-Bernoulli beam theory. The hydrodynamic loads generated by the flapping motion are calculated using the three-dimensional unsteady vortex lattice method. The finite element method is used to solve the coupled time-dependent equations of motion using an implicit solver for time integration. The results show improvement in the thrust and propulsive efficiency over a specific range of non-dimensional flexibility defined by the ratio of the elastic forces to fluid pressure forces. Structural and flow characteristics associated with the improved performance are discussed. As for geometric effects, the performance depends on the excitation frequency. At low frequencies, the improvement is continuous with increasing the aspect ratio in a manner similar to that of rigid tails. At higher frequencies, the improvement is limited to a region defined by aspect ratios that are less than 0.5. The extent of the improvement depends on the flexibility.
KW - aspect ratio
KW - elastic loads
KW - flexibility
KW - strong coupling
KW - three dimensional unsteady vortex lattice method
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U2 - 10.1088/1748-3190/ac220e
DO - 10.1088/1748-3190/ac220e
M3 - Article
C2 - 34450610
AN - SCOPUS:85116900303
SN - 1748-3182
VL - 16
JO - Bioinspiration and Biomimetics
JF - Bioinspiration and Biomimetics
IS - 6
M1 - 066008
ER -