In this paper we study the self-propulsion of a dumbbell micro-robot submerged in a viscous fluid. The micro-robot consists of two rigid spherical beads connected by a rod or a spring; the rod’s/spring’s length is changing periodically. The constant density of each sphere differs from the density of a fluid, while the whole micro-robot has neutral buoyancy. An effective oscillating gravity fiel...

0 10 20 30 −50 0 50 100 150 r (mm) U (m /s ) x/DB = 0.2 0 10 20 30 −10 −5 0 5 10 r (mm) V (m /s ) x/DB = 0.2 0 10 20 30 −50 0 50 100 150 r (mm) U (m /s ) x/DB = 0.6 0 10 20 30 −10 −5 0 5 10 r (mm) V (m /s ) x/DB = 0.6 0 10 20 30 −50 0 50 100 150 r (mm) U (m /s ) x/DB = 1.4 0 10 20 30 −10 −5 0 5 10 x/DB = 1.4 r (mm) V (m /s ) Experiment Raman et al. LES/HPDF Liu et al. Merci et al. Fig. 1. Mean ...

The aim of our study is to analyze the impact of insertion holes in the middle of obstacles on the flow around a surface-mounted cube, In order to do this; we studied four configurations of obstacles in a channel with a Reynods number based on obstacle height ReH = 40000. The hexahedral structured meshes were used to solve the fluid dynamics equations .The finite volume method are employed to s...

In this paper the numerical simulation of flow field in the new design dynamic cyclone separator is investigated. The effects of different geometrical parameters such as impeller diameter, number of vanes, length and the location of impeller is investigated. The Reynolds averaged Navier–Stokes equations with Reynolds stress turbulence model (RSM) were solved. The Eulerian-Lagrangian computation...

A numerical experiment is carried out to study the suitability of two-dimensional (2D) depth-averaged modeling for bend-flow simulation, in which the geometry of the studied channel is rectangular. Two commonly used 2D depth-averaged models for bend-flow simulation are considered in this study of which the bend-flow model includes the dispersion stress terms by incorporating the assumption of s...

This paper is motivated by the need to develop low cost, wireless velocity sensors for hydraulic research and application in streams. A velocity bend sensor (VBS) is a flexible plastic polyimide substrate sheet with an electronic resistor connected to a voltage divider. Drag of a moving fluid bends the sensor, changes the electronic resistance, and produces a voltage drop that can be related to...

An approach to obtain the mobility of nonspherical particles is proposed by averaging the drag force orientationally, and two other widely used approaches in the literature, the averaged-collision-integral and averaged-drift-velocity methods, are summarized and extended. The concept of orientationally averaged collision integrals based on Chapman-Enskog theory for small gas-phase ions is re-exa...

An automated discharge imaging system (ADIS), a non-intrusive and safe approach, was 12 developed for measuring river flows during flash flood events. ADIS consists of dual cameras to 13 capture complete surface images in the near and far fields. Surface velocities are accurately measured 14 using the Large Scale Particle Image Velocimetry (LSPIV) technique. The stream discharges are then 15 ob...

Measurement of river discharge during flooding events has especially been a challenging and dangerous task in the southwestern US, where flows can be flashy, laden with sediment, at high velocity. Small unoccupied aircraft systems (sUAS) deployed to access unsafe field sites capture imagery for measuring surface flow velocity discharge. This paper compares estimation eight sites—located or near...

We obtain hourly values of tail densities and of power law indices,  , of suprathermal (speeds above 2.48 times the solar wind speed) protons from power law fits to hourly velocity distribution functions in the solar-wind-frame. ACE/SWICS and ULEIS data, which often include very low counting statistics, are used to derive hourly proton phase space densities. We find that during part of the rec...