efflux time measurements are carried out for gravity draining of a liquid from a large cylindrical tank (where the flow is essentially laminar) through single exit pipe in the absence and presence of cetyl pyridinium chloride (cpc) surfactant solutions. the variables considered are initial height of liquid in the tank, dia. of tank, length of the exit pipe and concentration of surfactant. the d...

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We study the drag force experienced by an object slowly moving at constant velocity through a 2D granular material consisting of bidisperse disks. The drag force is dominated by force chain structures in the bulk of the system, thus showing strong fluctuations. We consider the effect of three important control parameters for the system: the packing fraction, the drag velocity and the size of th...

In this research numerical simulations are performed, using the multi-relaxation-time lattice Boltzmann method, in the range 3 ≤ β = w[d] ≤ 30 at Re = 100, 200 and 300, where β the blockage ratio, w is the equispaced distance between centers of cylinders, d is the diameter of the cylinder and Re is the Reynolds number, respectively. Special attention is paid to the effect of the equispaced dist...

Trains with different numbers of cars running in the open air were simulated using the delayed detached-eddy simulation (DDES). The numbers of cars included in the simulation are 3, 4, 5 and 8. The aim of this study was to investigate how train length influences the boundary layer, the wake flow, the surface pressure, the aerodynamic drag and the friction drag. To certify the accuracy of the me...

We work out a theory of the Coulomb drag current created under the ballistic transport regime in a one-dimensional nanowire by a ballistic non-Ohmic current in a nearby parallel nanowire. As in the Ohmic case, we predict sharp oscillation of the drag current as a function of gate voltage or the chemical potential of electrons. We also study dependence of the drag current on the voltage V across...

Drag-and-pop is an interaction technique designed to accelerate drag-and-drop on large screens. By animating potential targets and bringing them to the dragged object, drag-and-pop reduces the user effort required for dragging an object across the screen to a desired target. To preserve users’ spatial memory, targets are not moved away from their original location, but are instead stretched usi...

The current study explores the use of an automated direct/iterative design method for the reduction of drag for transport con gurations, including con gurations with engine nacelles. The method requires the user to choose a proper target-pressure distribution and then develops a corresponding airfoil section. The method can be applied to two-dimensional airfoil sections or to three-dimensional ...