Resources

Author(s): R. N. Bearon and W. M. Durham Many of the microscopic plankton that live in aquatic environments perform vertical migrations up and down through the water column each day to reach sunlight, acquire nutrients and avoid predators. However, these daily migrations can be thwarted by flow, which is ubiquitous in these environments, because it redirects their motility in other directions. This study explores how the shape of swimmers affects...

Author(s): Benjamin J. Walker, Kenta Ishimoto, and Eamonn A. Gaffney Minimal models are used frequently when building up intuition for microswimmers and their behaviors. In this paper, we highlight how the commonplace omission of rapid variation in the parameters used in these models can lead to qualitatively incorrect predictions, even in the simplest and most common models of swimmers near boundaries. Further, we show how appropriate, effective...

Author(s): Arjun Sharma and Donald L. Koch It is well-known and intuitive that addition of a dilute volume concentration of spheres increases the viscosity of a Newtonian liquid. We find that a viscoelastic liquid undergoing uniaxial extensional flow at small De (extension rate times the polymer relaxation time) experiences a larger increase in viscosity than the Newtonian case due to wakes of extra polymer stretch produced downstream of the spheres...

Author(s): Yoshinobu Yamamoto, Yukio Kaneda, and Yoshiyuki Tsuji A theory of the position dependence of the statistical average of the energy dissipation rate per unit mass (ϵ>) in the inertial sublayer of turbulent channel flow is proposed on the basis of the spirit of the Linear Response Theory (LRT) of turbulence. The theory with data consisting of a series of direct numerical simulations up to Reτ≈ 8000 suggests κϵ≈ 0.44 for the von Kármán...

Author(s): Hamza Issa, Giovanniantonio Natale, Gilles Ausias, and Julien Férec The suspension of Brownian rods in flow has a major effect in many engineering applications. We numerically examine Brownian rod suspensions through a rectangular channel with and without the effect of circular obstacles, taking into consideration the isotropic translational diffusion tensor using the finite element method. We develop a kinetic macro-model that reduces...

Author(s): Marina Pasquet, Frédéric Restagno, Isabelle Cantat, and Emmanuelle Rio In this work, we measure and model the thickness profile of soap films in the regime of large extensions and large extension rates. For this purpose, we developed an experiment to generate soap films up to two meters high at velocities of the order of a meter per second. We show that the thickness profile in the central part of the film is exponential and described...

Author(s): Gilles Tissot, André V. G. Cavalieri, and Étienne Mémin Stochastic modeling under location uncertainty considers conservation laws of quantities subject to a stochastic transport. This framework allows us to extend the linearized models of the type of resolvent analysis into a form which models the influence of turbulence onto coherent structures in a physically consistent manner, i.e. through a transport. We show the ability of this...