Sophie Ramananarivo

Sophie Ramananarivo
University of California, San Diego | UCSD · Department of Physics

PhD

About

22
Publications
2,021
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
459
Citations

Publications

Publications (22)
Article
Full-text available
We investigate the deformation in a uniform water flow of thin sheets perforated with parallel cuts. Through combined experiments and theory, we show that deployment is governed by the competition between fluid forces and sheet stretchability, which is prescribed by the cut pattern. Importantly, fluid loading is modulated by the local three-dimensi...
Poster
Full-text available
For a couple of decades, passive fog collectors (generally a fibrous mesh placed in the path of the fog) have been used to obtain data from fog or to harvest fresh water, for domestic use of for agriculture. Here, we present in situ force measurements on a model fog collector, composed of vertical fibers with a 40% solidity. We compare in situ wind...
Article
The flagella of microorganisms have provided inspiration for many synthetic devices, but they’re typically not easy to produce. A new class of swimmer makes it look simple by spontaneously growing a tail that it can whip to self-propel.
Article
Full-text available
Active navigation relies on effectively extracting information from the surrounding environment, and often features the tracking of gradients of a relevant signal-such as the concentration of molecules. Microfluidic networks of closed pathways pose the challenge of determining the shortest exit pathway, which involves the proper local decision-maki...
Preprint
Full-text available
Molecular motors are essential to the living, they generate additional fluctuations that boost transport and assist assembly. Self-propelled colloids, that consume energy to move, hold similar potential for the man-made assembly of microparticles. Yet, experiments showing their use as a powerhouse in materials science lack. Our work explores the de...
Article
Full-text available
Molecular motors are essential to the living, generating fluctuations that boost transport and assist assembly. Active colloids, that consume energy to move, hold similar potential for man-made materials controlled by forces generated from within. Yet, their use as a powerhouse in materials science lacks. Here we show a massive acceleration of the...
Article
Aeronautical studies have shown that subtle changes in aerofoil shape substantially alter aerodynamic forces during fixed-wing flight. The link between shape and performance for flapping locomotion involves distinct mechanisms associated with the complex flows and unsteady motions of an air- or hydro-foil. Here, we use an evolutionary scheme to mod...
Article
Advances in colloidal synthesis allow for the design of particles with controlled patches. This article reviews routes towards colloidal locomotion, where energy is consumed and converted into motion, and its implementation with active patchy particles. A special emphasis is given to phoretic swimmers, where the self-propulsion originates from an i...
Article
Classic models of fish schools and flying formations of birds are built on the hypothesis that the preferred locations of an individual are determined by the flow left by its upstream neighbor. Lighthill posited that arrangements may in fact emerge passively from hydro- or aerodynamic interactions, drawing an analogy to the formation of crystals by...
Article
• Roots play an important role in strengthening and stabilizing soils. Existing models predict that tensile strength and root abundance are primary factors that strengthen soil. This study quantified how both factors are affected by root developmental stage.• Focusing on early development of Avena fatua, a common grassland species with a fibrous ro...
Article
During cruising, the thrust produced by a self-propelled swimmer is balanced by a global drag force. For a given object shape, this drag can involve skin friction or form drag, both being well-documented mechanisms. However, for swimmers whose shape is changing in time, the question of drag is not yet clearly established. We address this problem by...
Article
Full-text available
Confined geometries usually involve reflected waves interacting together to form a spatially stationary pattern. A recent study on bio-locomotion, however, has reported that propagating wave kinematics can naturally emerge in a forced elastic rod, even with boundary conditions involving significant reflections. It has been shown that this particula...
Article
Birds and aquatic animals exploit the surrounding fluid to propel themselves in air or water. In inertial regimes, the mechanisms of propulsion are based on momentum transfer; by flapping wings or fins, animals accelerate fluid in their wake, creating a jet that propels them forward. The structures used to move can be flexible, and are thus likely...
Conference Paper
This project was conducted to increase understanding of the effect of root development on soil stability. Root development and relevant morphological and mechanical plant attributes were monitored in conjunction with the evolution of soil shear resistance. Avena fatua (wild oats) were grown in pots for one, three, and seven weeks, after which soil...
Article
We present in this fluid dynamics video a novel experimental setup with self-propelled swimmers on a free surface. The swimmers, modeled as flexible thin filaments, are subjected to external electromagnetic forcing driving a propagating elastic wave that gives rise to self- propulsion. The fluid-structure interaction problem of these passive anguil...
Article
Full-text available
Swimmers in nature use body undulations to generate propulsive and manoeuvring forces. The anguilliform kinematics is driven by muscular actions all along the body, involving a complex temporal and spatial coordination of all the local actuations. Such swimming kinematics can be reproduced artificially, in a simpler way, by using the elasticity of...
Article
Full-text available
Saving energy and enhancing performance are secular preoccupations shared by both nature and human beings. In animal locomotion, flapping flyers or swimmers rely on the flexibility of their wings or body to passively increase their efficiency using an appropriate cycle of storing and releasing elastic energy. Despite the convergence of many observa...

Network

Cited By