Bulletin of the American Physical Society
77th Annual Meeting of the Division of Fluid Dynamics
Sunday–Tuesday, November 24–26, 2024; Salt Lake City, Utah
Session A04: General Biofluid Mechanics I: Bioinspired Fluid Mechanics |
Hide Abstracts |
Chair: Omid Amili, University of Toledo Room: Ballroom D |
Sunday, November 24, 2024 8:00AM - 8:13AM |
A04.00001: ABSTRACT WITHDRAWN
|
Sunday, November 24, 2024 8:13AM - 8:26AM |
A04.00002: Exploring the multi-functional potential of a Giant-Larvacean-inspired undulating module for fluid pumping and propulsion. Yicong Fu, Tianbin Liu, Sunghwan Jung Aquatic microplastic is a pollution crisis. Current cleaning methods such as tow nets or propeller suction are unideal due to low maneuverability and severe biological intrusion. We present a novel modular robot biomimetically inspired by Giant Larvaceans. A rectangular flexible panel with non-uniform rigidity is positioned in 2D confinement in quiescent water, actively undulated at the anterior, and sustains passive flapping in the posterior portion. An actuation frequency between 0.5 and 9 Hz paired with different bending rigidities was tested, measuring pumping flow rates (Q) and propulsive forces (T) were simultaneously measured. Interestingly, different trends in Q and T were observed with frequency. Particularly, three regimes can be identified for Q, a constant plateau within the frequency range of 2 to 6 times the resonance plus two linear ranges below or above. Two continuously increasing regimes can be identified for T, but separated by distinctive slopes. Phase-averaged vorticity and Lagrangian Coherent Structures show the transitions between regimes are correlated with changes in the wake vortex structure, proving the potential to theoretically model Q by superposition of the panel-motion-induced velocity and vortex-induced velocities. The elongated-body theory validated the propulsive force and drew connections between Q and T. Finally, the robotic prototype shows promising potential to assemble, maneuver, navigate, and multitask for microplastic collecting missions. |
Sunday, November 24, 2024 8:26AM - 8:39AM |
A04.00003: Optimal clearance rates by a model oyster Sophie MacDonald, Neil J Balmforth, Miranda Holmes-Cerfon Oysters are a significant factor in understanding water quality in coastal regions due to their function as filter feeders and their global range. Mathematical studies of bivalve filtration have typically modeled the animals as a pair of siphons, in line with the morphology of species like mussels and clams which have extendable appendages that extend from the body in order to reach into ambient currents. This is not the case with oysters where water is drawn directly in through a distributed opening between the two shells, and then expelled as a more localized jet, passing over the filtering gills in between. As a step towards understanding the filtration effectiveness of oysters, we consider the flow created by a single oyster in an otherwise motionless tank. For simplicity, we adopt a two-dimensional annular geometry in which the oyster and tank are taken to be the circular inner and outer walls; a prescribed radial velocity at the inner wall (the oyster) drives Stokes’ flow within the annulus. The transport arising from the resulting flow pattern is then gauged by solving an advection-diffusion equation for a passive scalar where concentration is held fixed at the outer wall (the tank) but set to zero at inflow or outflow to the oyster, assuming that filtration occurs immediately on entry. We investigate how different pumping arrangements and scalar diffusivities (Peclet numbers) impact the clearance rate of the passive scalar. |
Sunday, November 24, 2024 8:39AM - 8:52AM |
A04.00004: Universal leaky channel inspired by mobula filters Xinyu Mao, Irmgard Bischofberger, Anette E. Hosoi The filtering apparatus of mobula rays resembles cross-flow filters but demonstrates unconventional anticlogging performance. The permeability and selectivity of cross-flow filters are rationally designed in industry, yet the rationales behind mobula filters largely remain elusive. To bridge both types of filtration, we analyze the permeability-selectivity trade-off in a universal leaky channel inspired by mobula filters, which contains a main channel and two parallel arrays of side pores for leakage. Through experiments, theory, and simulations, we investigate water flow at the pore scale, unveiling a phase diagram that includes pore-flow, transition, and vortex regimes. Each flow regime features distinct scaling laws for water permeability and particle selectivity. We further establish a diagram characterizing the trade-off between permeability and selectivity for our universal leaky channel. We demonstrate that mobula filters reside in a parameter space specified by physical and biological constraints, achieving an elegant balance between permeability and selectivity for breathing and filter feeding. |
Sunday, November 24, 2024 8:52AM - 9:05AM |
A04.00005: Modeling of Pulsing Corals and Mixing Sarah Malone, Brittany Jae Leathers, Laura A Miller, Shilpa Khatri The motion of pulsing corals, a soft coral belonging to the Xeniidae family, is highly intriguing because of the unique movement that it uses to generate fluid flow around it. This energetically expensive motion is not used for locomotion but is instead believed to aid the photosynthesis process for their endosymbiotic algae. The photosynthetic algae live within the coral tissue and produce energy for the coral polyp. We solve for the flow created by the pulsing coral using anodal immersed finite element-finite difference method, an off-shoot of the classic immersed boundary method to model this fluid-structure interaction process. We then employ a mix of analyses to quantify the flow and mixing over a pulsing period. Additionally, we vary the kinematic, flow, and muscle parameters that govern the resulting tentacle motion and fluid flow to understand the parameters that result in more or less mixing. |
Sunday, November 24, 2024 9:05AM - 9:18AM |
A04.00006: Active fluid mixing generated by a robotic coral Diego Tapia Silva, Dustin P Kleckner, Shilpa Khatri Xeniid corals are unique among animals as they exhibit active motion for purposes other than locomotion. The corals use their tentacles to pulse the surrounding fluid, removing oxygen waste and enhancing the photosynthetic rate of their symbiotic algae. To understand the fluid dynamics involved, we developed a robotic coral that mimics the pulsing motion of the corals. We imaged the active flows generated by the robot and collected 3D particle tracking velocimetry (PTV) using a novel high-speed two-color scanning volumetric laser-induced fluorescence (H2C-SVLIF) imaging technique. We present flow visualizations and quantify the mixing metrics of the coral in intermediate Reynolds number regime. |
Sunday, November 24, 2024 9:18AM - 9:31AM |
A04.00007: Biohybrid Robot Jellyfish act as Buoyancy-Controlled Vertical Profiling Samplers Kelsi M Rutledge, John O. Dabiri In light of a changing climate, monitoring ocean health is more vital than ever. Recent technology has demonstrated the ability to robotically control the unidirectional swimming of moon jellyfish. Here, we assess the potential of biohybrid robot jellyfish to act as vertical ocean profilers, similar to buoyancy-controlled Argo floats routinely used for ocean sampling. Biohybrid jellyfish equipped with positively buoyant microcontrollers and ballasts were deployed in a vertical tank and tracked swimming repeated vertical profiles (1 profile = swim down, float up). Descent speed was found to generally correlate with jellyfish volume. Biohybrid jellyfish were also tested in a coastal ocean environment, equipped with a temperature sensor to monitor the surrounding environment during profiles. The successful demonstration of vertical-profiling biohybrid robot jellyfish is an important first step toward realizing this new ocean monitoring platform. Additionally, this platform would address many of the limitations of current sensing technology due to its low cost, global availability, small size, minimal power demand, and potential scalability. |
Sunday, November 24, 2024 9:31AM - 9:44AM |
A04.00008: Efficient Swimming with Flexible Caudal Fins: Insights from Coupled Fluid-Membrane Interaction Modeling Sushrut Kumar, Jung-Hee Seo, Rajat Mittal The fluid dynamics of marine animals' propulsion, particularly fish, can inspire the development of efficient underwater autonomous systems. Various fish species employ highly deformable fins reinforced with relatively stiffer rays. Numerical modeling can provide insights into the hydrodynamics of deformable fin propulsors but can be challenging due to the extremely low mass ratio of the fin material, leading to high added-mass effects. In this study, we utilize the sharp interface immersed boundary method coupled with a membrane deformation model to perform a fully coupled hydroelastic simulation of the flexible caudal fin. The detrimental numerical instability associated with strong added-mass effects typically requires computationally expensive implicit coupling for stabilization. However, we employ an added mass stabilization scheme (AMaSS), which allows for the use of explicit coupling between the fluid and membrane solvers, thereby reducing computational costs. The developed numerical model is then used to systematically study the effect of material properties and fin kinematics on the fin's performance. Our findings reveal that flexible fins exhibit superior efficiency in propulsion compared to their rigid counterparts. To further understand the mechanics contributing to hydrodynamic force generation, we utilize the force partitioning method to decompose the hydrodynamic forces into distinct components, providing a detailed analysis of the contributions from different flow structures and membrane kinematics. The insights gained from this study can inform the design of bio-inspired underwater vehicles and robotic systems, enhancing their propulsion efficiency and maneuverability. |
Sunday, November 24, 2024 9:44AM - 9:57AM |
A04.00009: Effects of trailing edge shape on experimental propulsive performance and wake structure of biospired pitching panels Justine John Alegasin Serdoncillo, Justin T King, Melissa A Green Prior experimental research on bioinspired propulsion has often modeled a caudal fin as a trapezoidal panel to investigate propulsive performance. Performance is often directly measured using fixed-velocity or self-propelled swimming experiments, and is correlated with observations of the wake structure based on flow field measurements. The current work analyzes experimental data for five different panel planforms of varying trailing edge shape (forked to pointed geometries) that represent a range of propulsive appendages of aquatic animals. Phase-averaged particle image velocimetry (PIV) is used to capture velocity fields that are interrogated using finite-time Lyapunov exponents (FTLE). Maximizing features of FTLE scalar fields, such as ridges and saddle-like intersections have been shown to correlate with important dynamic phenomena such as vortex shedding, flow separation, and peaks in propulsive performance. While previous work has highlighted certain geometries that produce higher thrust or efficiency, this work will explore the associated changes in the wake structure uncovered by the FTLE analysis. |
Sunday, November 24, 2024 9:57AM - 10:10AM |
A04.00010: The influence of flow disturbances on the dynamics and propulsion of flexible oscillating foils Abdur Rehman, Daniel Floryan The environments that animals swim in are invariably complex, littered with vortices, gusts, and other disturbances. To understand how swimmers contend with these spatiotemporal heterogeneities, we explore the dynamics and propulsive performance of a flexible foil in disturbed flows. Flexibility is modeled via a torsional spring at the leading edge, which allows the foil to passively pitch in response to an applied heaving motion and fluid forces, calculated using a panel method. The foil is exposed to a variety of flow disturbances, including a wavy freestream, vortex streets, and periodic gusts. As the foil’s oscillations become large and the disturbances strengthen, the foil’s wake becomes increasingly non-planar, and the oncoming flow disturbances become deformed. This changes the bound circulation and induced velocity profiles, leading to deviations from predictions made by a thin airfoil theory. Impulse theory is employed to understand the deviations from linearity. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2025 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700