Daniel Floryan
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View article: Propulsion of a flexible foil in a wavy flow: resonance, antiresonance and destructive self-interference
Propulsion of a flexible foil in a wavy flow: resonance, antiresonance and destructive self-interference Open
Swimming and flying animals demonstrate remarkable adaptations to diverse flow conditions in their environments. In this study, we aim to advance the fundamental understanding of the interaction between flexible bodies and heterogeneous fl…
View article: Propulsion of a flexible foil in a wavy flow: resonance, antiresonance, and destructive self-interference
Propulsion of a flexible foil in a wavy flow: resonance, antiresonance, and destructive self-interference Open
Swimming and flying animals demonstrate remarkable adaptations to diverse flow conditions in their environments. In this study, we aim to advance the fundamental understanding of the interaction between flexible bodies and heterogeneous fl…
View article: Particle Re-Suspension in Two-Phase Dispersed Rayleigh-Bénard Convection
Particle Re-Suspension in Two-Phase Dispersed Rayleigh-Bénard Convection Open
The process by which particles are entrained by the fluid in Rayleigh-Bénard convection is studied by means of particle-resolved numerical simulations in a periodic domain at a Rayleigh number of $10^7$. The fluid Prandtl number is 1 and t…
View article: On instabilities in neural network-based physics simulators
On instabilities in neural network-based physics simulators Open
When neural networks are trained from data to simulate the dynamics of physical systems, they encounter a persistent challenge: the long-time dynamics they produce are often unphysical or unstable. We analyze the origin of such instabiliti…
View article: Group cohesion and passive dynamics of a pair of inertial swimmers with three-dimensional hydrodynamic interactions
Group cohesion and passive dynamics of a pair of inertial swimmers with three-dimensional hydrodynamic interactions Open
When swimming animals form cohesive groups, they can reap several benefits. Our understanding of collective animal motion has traditionally been driven by models based on phenomenological behavioral rules, but more recent work has highligh…
View article: Poster: SCALE DIVISION
Poster: SCALE DIVISION Open
The 18 curves at the bottom are from velocity signals in high-Reynolds number pipe flow.
View article: Propulsive performance of oscillating plates with time-periodic flexibility
Propulsive performance of oscillating plates with time-periodic flexibility Open
We use small-amplitude inviscid theory to study the swimming performance of a flexible flapping plate with time-varying flexibility. The stiffness of the plate oscillates at twice the frequency of the kinematics in order to maintain a symm…
View article: Self-similar, spatially localized structures in turbulent pipe flow from a data-driven wavelet decomposition
Self-similar, spatially localized structures in turbulent pipe flow from a data-driven wavelet decomposition Open
This study aims to extract and characterize structures in fully developed pipe flow at a friction Reynolds number of $\text{Re}_τ= 12\,400$. To do so, we employ data-driven wavelet decomposition (DDWD) [D.~Floryan and M.~D.~Graham, PNAS 11…
View article: A fundamental limit on energy savings in controlled channel flow, and how to beat it
A fundamental limit on energy savings in controlled channel flow, and how to beat it Open
We derive a limit on energy savings in controlled channel flow. For flow in a channel driven by pressure, shear, or any combination of the two, and controlled via wall transpiration or spanwise wall motion, the uncontrolled laminar state r…
View article: Propulsive performance of oscillating plates with time-periodic flexibility
Propulsive performance of oscillating plates with time-periodic flexibility Open
We use small-amplitude inviscid theory to study the swimming performance of a flexible flapping plate with time-varying flexibility. The stiffness of the plate oscillates at twice the frequency of the kinematics in order to maintain a symm…
View article: Charts and atlases for nonlinear data-driven models of dynamics on manifolds.
Charts and atlases for nonlinear data-driven models of dynamics on manifolds. Open
We introduce a method for learning minimal-dimensional dynamical models from high-dimensional time series data that lie on a low-dimensional manifold, as arises for many processes. For an arbitrary manifold, there is no smooth global coord…
View article: Data-driven discovery of intrinsic dynamics
Data-driven discovery of intrinsic dynamics Open
Dynamical models underpin our ability to understand and predict the behavior of natural systems. Whether dynamical models are developed from first-principles derivations or from observational data, they are predicated on our choice of stat…
View article: Discovering multiscale and self-similar structure with data-driven wavelets
Discovering multiscale and self-similar structure with data-driven wavelets Open
Significance Multiscale structure is all around us: in biological tissues, active matter, oceans, networks, and images. Identifying the multiscale features of these systems is crucial to our understanding and control of them. We introduce …
View article: Exact Coherent States and the Nonlinear Dynamics of Wall-Bounded Turbulent Flows
Exact Coherent States and the Nonlinear Dynamics of Wall-Bounded Turbulent Flows Open
Wall-bounded turbulence exhibits patterns that persist in time and space: coherent structures. These are important for transport processes and form a conceptual framework for important theoretical approaches. Key observed structures includ…
View article: Distributed flexibility in inertial swimmers
Distributed flexibility in inertial swimmers Open
We study a linear inviscid model of a passively flexible swimmer with distributed flexibility, calculating its propulsive performance and optimal distributions of flexibility. The frequencies of actuation and mean stiffness ratios we consi…
View article: Connections between resonance and nonlinearity in swimming performance of a flexible heaving plate
Connections between resonance and nonlinearity in swimming performance of a flexible heaving plate Open
We investigate the role of resonance in finite-amplitude swimming of a\nflexible flat plate in a viscous fluid. The role of resonance in performance\nremains unclear for two reasons: i) a lack of definition of resonance for the\nfully-coup…
View article: Swimmers’ wake structures are not reliable indicators of swimming performance
Swimmers’ wake structures are not reliable indicators of swimming performance Open
The structure of swimmers' wakes is often assumed to be an indicator of swimming performance, that is, how momentum is produced and energy is consumed. Here, we discuss three cases where this assumption fails. In general, great care should…
View article: Swimmers' wakes are not reliable indicators of swimming performance
Swimmers' wakes are not reliable indicators of swimming performance Open
The structure of swimmers' wakes is often assumed to be an indicator of swimming performance. Here, we discuss three cases where this assumption fails. In general, great care should be taken in deriving any conclusions about swimming perfo…
View article: Clarifying the relationship between efficiency and resonance for flexible inertial swimmers
Clarifying the relationship between efficiency and resonance for flexible inertial swimmers Open
We study a linear inviscid model of a passively flexible swimmer, calculating its propulsive performance, eigenvalues and eigenfunctions with an eye towards clarifying the relationship between efficiency and resonance. The frequencies of a…
View article: Efficient cruising for swimming and flying animals is dictated by fluid drag
Efficient cruising for swimming and flying animals is dictated by fluid drag Open
Significance Almost 30 y ago, researchers discovered that a great variety of efficient swimmers cruise in a narrow range of Strouhal numbers, a dimensionless number describing the kinematics of swimming. Almost 15 y later, separate researc…
View article: Scaling and Performance of Simultaneously Heaving and Pitching Foils
Scaling and Performance of Simultaneously Heaving and Pitching Foils Open
We consider the propulsive performance of an unsteady heaving and pitching foil, experimentally studying an extensive parameter space of motion amplitudes, frequencies, and phase offsets between the heave and pitch motions. The phase offse…
View article: Bio-inspired underwater propulsors
Bio-inspired underwater propulsors Open
Here we present a general overview of bio-inspired propulsion. We identify the major types of aquatic swimmers (oscillatory, undulatory, pulsatile, and drag-based) and break down their mechanisms for thrust production (drag-based, lift-bas…
View article: Swimming speed has little impact on fish-like swimming performance
Swimming speed has little impact on fish-like swimming performance Open
Experiments are reported on the performance of a pitching and heaving two-dimensional foil in a water channel in either continuous or intermittent motion. We find that the thrust and power are independent of the mean freestream velocity fo…
View article: Publisher's Note: Impact of trailing edge shape on the wake and propulsive performance of pitching panels [Phys. Rev. Fluids <b>2</b>, 014702 (2017)]
Publisher's Note: Impact of trailing edge shape on the wake and propulsive performance of pitching panels [Phys. Rev. Fluids <b>2</b>, 014702 (2017)] Open
Received 22 May 2017DOI:https://doi.org/10.1103/PhysRevFluids.2.059901©2017 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasLocomotionVortex flowsFluid Dynamics
View article: Publisher's Note: Nonsinusoidal gaits for unsteady propulsion [Phys. Rev. Fluids <b>2</b>, 053101 (2017)]
Publisher's Note: Nonsinusoidal gaits for unsteady propulsion [Phys. Rev. Fluids <b>2</b>, 053101 (2017)] Open
Received 22 May 2017DOI:https://doi.org/10.1103/PhysRevFluids.2.059902©2017 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasLocomotionSwimmingVortex flowsFluid Dynamics