Efficient swimming using flexible fins with tapered thickness

Effect of actuation method on hydrodynamics of elastic plates oscillating at resonance

“…Comparison of cruising speed of elastic plates with different shapes revealed that the contracting fin shape facilities a faster swimming in comparison to fins with the diverging shape (Engels et al 2017). It was also reported that fins with tapered thickness yield greater efficiency for a wider range of actuation frequencies than fins with uniform thickness (Yeh, Li & Alexeev 2017). Simulations of internally actuated fins with passive fin attachments revealed that such attachments yield improved hydrodynamic performance (Yeh & Alexeev 2016a).…”

“…2017). It was also reported that fins with tapered thickness yield greater efficiency for a wider range of actuation frequencies than fins with uniform thickness (Yeh, Li & Alexeev 2017). Simulations of internally actuated fins with passive fin attachments revealed that such attachments yield improved hydrodynamic performance (Yeh & Alexeev 2016 a ).…”

Distributed flexibility in inertial swimmers

“…In most studies, the characteristic fluid mass is of the same order as the characteristic body mass, as in fliers (many of these studies are motivated by insect flight). Distributed flexibility has been modelled in several ways: as a uniform elastic plate with virtual linear springs at several control points (the virtual linear Distributed flexibility in inertial swimmers 888 A24-3 springs attach the elastic sheet to points with a priori known motions, mimicking veins in insect wings) (Shoele & Zhu 2013); as an elastic plate with varying material properties (Moore 2015); and as an elastic plate with homogeneous material properties but varying thickness (Yeh, Li & Alexeev 2017). Both Shoele & Zhu (2013) and Yeh et al (2017) found that plates with stiff leading edges produced thrust curves that had lower, but broader, peaks than those of uniformly flexible plates, and that plates with stiff leading edges were broadly more efficient than uniformly flexible plates.…”

“…Distributed flexibility has been modelled in several ways: as a uniform elastic plate with virtual linear springs at several control points (the virtual linear Distributed flexibility in inertial swimmers 888 A24-3 springs attach the elastic sheet to points with a priori known motions, mimicking veins in insect wings) (Shoele & Zhu 2013); as an elastic plate with varying material properties (Moore 2015); and as an elastic plate with homogeneous material properties but varying thickness (Yeh, Li & Alexeev 2017). Both Shoele & Zhu (2013) and Yeh et al (2017) found that plates with stiff leading edges produced thrust curves that had lower, but broader, peaks than those of uniformly flexible plates, and that plates with stiff leading edges were broadly more efficient than uniformly flexible plates. Moore (2015) optimized the stiffness (mean and distribution) at fixed frequencies for thrust, and found that a plate that is rigid except at the leading edge (where it has a torsional spring) produced greater thrust than any other flexible plate (although the thrust is not much greater than that produced by a plate with linearly distributed flexibility).…”

Efficient aquatic locomotion using elastic propulsors with hybrid actuation

“…The plate is discretized with 21 nodes in the length and 11 nodes in the width, so that and in LB units. Further details and validation of our computational framework can be found elsewhere (Masoud & Alexeev 2010, 2012; Mao & Alexeev 2014; Yeh & Alexeev 2014; Yeh, Li & Alexeev 2017; Yeh, Demirer & Alexeev 2019; Demirer et al. 2021).…”