Self-organization of a biologically motivated swarm into smaller subgroups of different velocities is found by solving a 1-dimensional adaptive-velocity swarm, in which the velocity of an agent is averaged over a finite local radius of influence. Using a mean field model in phase space, we find a dependence of this group-division phenomenon on the typical scales of the initial swarm in the posi...

The flow patterns emerging at a catheter migrating close to the simulated superior vena cava (SVC) wall has been investigated for jet to cross stream velocity ratios of 3 and 6 experimentally. As the catheter moves close to the SVC wall, changes in the jet behavior can potentially cause health problems to the patient. In this study, time-averaged velocity, vorticity, and Reynolds stress correla...

The shear flow of two-dimensional foams is probed as a function of shear rate and disorder. Disordered, bidisperse foams exhibit strongly shear rate dependent velocity profiles. This behavior is captured quantitatively in a simple model based on the balance of the time-averaged drag forces in the system, which are found to exhibit power-law scaling with the foam velocity and strain rate. Disord...

We report simulations of a two-dimensional, dense, bidisperse system of inelastic hard disks falling down a vertical tube under the influence of gravity. We examine the approach to jamming as the average flow of particles down the tube is slowed by making the outlet narrower. Defining coarse-grained velocity and stress fields, we study two-point temporal and spatial correlation functions of the...

Introduction: Nontriggered phase-contrast (PC)-MR has been proposed for measurement of time-averaged velocity [1]. However, gradient-echo PC-MR is biased by in-flow enhancement when typical flip angles and slice widths are used, leading to velocity overestimation [2]. We hypothesize that nontriggered PCsteady state free precession (SSFP), which exhibits less signal variation over the cardiac cy...

The isometric and isotonic contractile properties of the cross-striated adductor muscle of the bay scallop (Argopecten irradians) were measured in vitro at 10, 15 and 20 degrees C. The length at which twitch force was maximal as a function of the closed length in situ (L0/Lcl) averaged 1.38 +/- 0.01 (mean +/- S.E.M.) at 10 degrees C. This length is very close to the typical length at maximum ga...

We present a model for generalized Newtonian fluid flow through a porous medium. In the model the dependence of the fluid viscosity on the velocity is replaced by a dependence on a smoothed (locally averaged) velocity. With appropriate assumptions on the smoothed velocity, existence of a solution to the model is shown. Two examples of smoothing operators are presented in the appendix. A numeric...

Abs ract : In the present paper, the development of a high-resolution PIV-PLIF combined system for the simultaneous measurements of velocity and passive scalar concentration fields is described. The high-resolution PIV-PLIF combined system is used to perform the simultaneous whole-field measurements of velocity and concentration in the near field of a turbulent jet mixing flow. The characterist...