Search arXivSearch

arXiv · 2503.08304

Propulsion of flapping foils undergoing in-plane clap-and-fling and deviation motions

Abstract

This study examines the performance of two flapping flat-plate foils interacting with each other while generating thrust at a Reynolds number of 800 through two-dimensional numerical simulations. These fluid dynamics simulations were conducted with a commercial computational fluid dynamics solver implementing a finite-volume method and an overset mesh capability. The foils performed a combined motion involving pitching, heaving, and deviation. Both foils exhibit similar movements, with one foil mirroring the other. The heaving and pitching motions occur at the same frequency but with a phase shift between them. The effects of varying the phase shift and the minimum spacing between the foils during motion were first explored. The study revealed that a maximum efficiency of 0.542 can be achieved by using two foils, representing an increase of 13.5% relative to the optimal single-foil case. Then, the impacts of the deviation motion were investigated. The deviation motion was introduced with a frequency twice as fast as the other motions, and a phase shift relative to the heaving motion. The other parameters such as the minimum spacing between the foils, the heaving and pitching amplitudes, and the frequency were those of the best configuration without deviation. The numerical simulations demonstrated that deviation can increase efficiency further to a value of 0.560, a relative increase of 3.95%.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Antoine Papillon, Mathieu Olivier. 2025-03-11. Propulsion of flapping foils undergoing in-plane clap-and-fling and deviation motions. https://arxiv.org/abs/2503.08304

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Cross-helicity and chaotic dynamics of full-disc solar magnetic field

Using the results of laboratory experiments and direct numerical simulations, as well as observations of the full-disc solar magnetic field and sunspot number dynamics, it is demonstrated that cross-helicity can dominate the decaying part of the frequency power spectra of the magnetic field generated by a magnetohydrodynamic (MHD) dynamo in chaotic/turbulent swirling flows for sufficiently strong MHD turbulence (including the solar dynamo). The theoretical consideration is based on a Kolmogorov-like phenomenology within the framework of the distributed chaos concept. It is also shown that the solar full-disc magnetic field for the last two solar cycles with weak magnetic activity exhibits deterministic chaotic behavior concentrated around the equator.

physics.flu-dyn

Manifestation of spurious currents and interface regularization in wind turbulence over fast-propagating waves

Accurate simulation of wind turbulence over fast-propagating waves requires interface-capturing methods that suppress numerical artifacts while accurately resolving momentum transfer across the interface. In high wave-age regimes, numerical errors at the air-water interface can reach magnitudes comparable to the physical flow, directly affecting predicted turbulence statistics. This study examines widely used interface-capturing techniques to evaluate how curvature estimation and flux discretization influence wind-wave simulations through the resulting spurious currents and interface regularization. A systematic assessment is performed using static and translating droplet benchmarks, together with solitary and monochromatic wave cases, to identify and quantify the dominant numerical error mechanisms. In addition, comparison with experimental measurements reveals how these primary error sources manifest in coupled wind-wave simulations. These findings clarify the numerical origin of the observed discrepancies and underscore the importance of accurate curvature and flux treatment in high wave-age regimes, without which numerical artifacts risk being misattributed to genuine wind-wave physics.

physics.flu-dyn

A reconfigurable multi-axis cyber-physical framework for multi-regime fluid--structure interaction experiments

Fluid--structure interaction (FSI) experiments are typically built around mechanical dynamics and constraints imposed by the physical apparatus, so changing mass, stiffness, damping, or allowable motion often requires hardware reconfiguration. Here we present a reconfigurable cyber-physical framework in which these properties are instead assigned through software-defined dynamics. The system provides three translational and one rotational degree of freedom, each independently configurable as prescribed, load-responsive, or locked, with operating roles that can also be reassigned during a running experiment. Measured forces and torques are incorporated into real-time virtual dynamic models, while a common supervisory architecture coordinates multi-axis motion, mode switching, synchronized data acquisition, and diagnostic positioning. The prescribed-motion pathway is validated using a pitching hydrofoil by comparison with published thrust and power scaling trends, while the load-responsive pathway is evaluated using an active-heave/passive-pitch benchmark that reproduces the expected frequency-dependent resonant response over the tested conditions. The same platform is then reconfigured for intra-cycle active--passive pitching, coordinated vertical-axis turbine-surrogate motion, force-driven passive surge, and automated multilayer stereoscopic particle image velocimetry. These results demonstrate that distinct FSI boundary conditions and measurement requirements can be implemented within a common motion, sensing, and control architecture. By treating mechanical roles and constraints as software-defined experimental variables, the framework provides a reusable basis for reconfigurable FSI experiments without redesigning the underlying platform for each application.

physics.flu-dyn