We investigate the problem of falling paper by solving the two dimensional Navier-Stokes equations subject to the motion of a free-falling body at Reynolds numbers around 10(3). The aerodynamic lift on a tumbling plate is found to be dominated by the product of linear and angular velocities rather than velocity squared, as appropriate for an airfoil. This coupling between translation and rotati...

We have measured the trajectory and visualized the wake of a single sphere falling in a fluid confined between two closely spaced glass plates (a Hele-Shaw cell). The position of a sedimenting sphere was measured to better than 0.001d , where d is the sphere diameter, for Reynolds numbers (based on the terminal velocity) between 20 and 330, for gaps between the plates ranging from 1.014d to 1.4...

[Purpose] The aim of this study was to examine the effects of balance training and muscle training around the ankle joints on the gait of elderly people who have experienced a fall. [Subjects] Twenty-six elderly people with a risk of falling and a Berg Balance Scale score of 37 to 50 points who had experienced a fall in the last year were randomly and equally assigned to either a balance traini...

Reconfigurable modular robots have the ability to use different gaits and configurations to perform various tasks. A rolling gait is the fastest currently implemented gait available for traversal over level ground and shows dramatic improvements in efficiency. In this work, we analyze and implement a sensor-based feedback controller to achieve dynamic rolling for a loop robot. The robot senses ...

The motion planning problem of a free-falling cat is investigated. Nonholonomicity arises in a free-falling cat subject to nonintegrable velocity constraints or nonintegrable conservation laws. When the total angular momentum is zero, the rotational motion of the cat subjects to nonholonomic constraints. The equation of dynamics of a free-falling cat is obtained by using the model of two symmet...

Abstract. Weather radars measure rainfall in altitude, whereas hydro-meteorologists are mainly interested at ground level. During their fall, drops advected by the wind, which affects location of measured field. The governing equation a rain drop's motion relates acceleration to forces gravity and buoyancy along with drag force. It depends non-linearly on instantaneous relative velocity between...

The Role of Rain Simulator Height and Rainfall Terminal Velocity Changes in Different Components Runoff Sediment

abstract in the present article, effective parameters of the buoyant jets have been evaluated in the stagnant ambient fluid. the jet parameters, geometry parameters and environmental parameters are investigated. using dimensional analysis, a set of dimensionless functions was obtained. to achieve the exact functions, a physical model was built in the hydraulic laboratory of shahid chamran unive...