An Experimental Study of the Fluctuations in Granular Drag

2000 ◽  
Vol 627 ◽  
Author(s):  
István Albert ◽  
Pál Tegzes ◽  
Réka Albert ◽  
John Sample ◽  
Albert-László Barabási ◽  
...  
Keyword(s):  
Experimental Study ◽  
Long Range ◽  
Drag Force ◽  
Granular Medium ◽  
Force Chains ◽  
Stick Slip ◽  
Granular Drag

ABSTRACTWe study fluctuations in the drag force resisting the motion of an object being pulled through a dense spherical granular medium. These fluctuations are stick-slip in nature due to the jamming and reorganization of the grains. The fluctuations in the force are periodic at small depths, but they become “stepped” at large depths. We interpret this transition as a consequence of the long-range nature of the force chains.

Stick-slip mechanism in a granular medium

2010 ◽  
Vol 46 (6) ◽  
pp. 600-605 ◽  
Author(s):  
A. P. Bobryakov
Keyword(s):  
Granular Medium ◽  
Stick Slip ◽  
Slip Mechanism

Transmission mechanisms of NMR long-range J(13C,19F) scalar couplings in 1-F,4-X-cubanes: a DFT and experimental study

2006 ◽  
Vol 104 (4) ◽  
pp. 485-492 ◽  
Author(s):  
RubéN H. Contreras ◽  
Ángel L. Esteban ◽  
Ernesto DÍez ◽  
Nicholas J. Head ◽  
Ernest W. Della
Keyword(s):  
Experimental Study ◽  
Long Range ◽  
Scalar Couplings ◽  
Transmission Mechanisms

The Adoption of the Bow and Arrow: A Model Based on Experimental Performance Characteristics

2013 ◽  
Vol 78 (3) ◽  
pp. 553-569 ◽  
Author(s):  
Steve A. Tomka
Keyword(s):  
Experimental Study ◽  
Long Range ◽  
New World ◽  
Prey Species ◽  
Game Species ◽  
Experimental Performance ◽  
Hunting Strategies ◽  
Bow And Arrow ◽  
Game Hunting ◽  
Over Time

AbstractThe timing of the arrival of the bow and arrow in the New World and reasons for its adoption have long been discussed by archaeologists. It typically has been assumed that the bow and arrow provided mechanical and physical advantages over the atlatl and dart, particularly in long-range killing power. This experimental study examines the effectiveness of traditional bows and arrows to deliver lethal wounds to prey species of different sizes. The results suggest that the bow and arrow was effective in hunting prey species such as antelope and deer but ineffective in bringing down larger animals unless changes in hunting strategies were adopted. In contrast, the atlatl and dart would have excelled in large game hunting. It is proposed that the adoption of the bow and arrow and the abandonment of the atlatl and dart were conditioned by their distinct performance advantages and changes in the game species targeted over time.

Experimental Study of the Vertical Hydraulic Drag Force on Regular Tetrahedron

2013 ◽  
Vol 860-863 ◽  
pp. 1547-1550
Author(s):  
Rui Le ◽  
Wei Jiang ◽  
Qi Liu ◽  
Nan Chang Sun ◽  
Bing Xu
Keyword(s):  
Experimental Study ◽  
Drag Coefficient ◽  
Drag Force ◽  
Vertical Velocity ◽  
Hydraulic Engineering ◽  
Hydraulic Drag ◽  
Regular Tetrahedron ◽  
Impact Effect ◽  
Drag Forces ◽  
The Impact

It is well known that the hydraulic drag force on objects cant be ignored in computing the movement of objects in water. And the drag forces on sphere and cuboids have long been studied. While in hydraulic engineering, objects with regular tetrahedron shape are widely used to form the foundation and temporary dam for they can interlock each other to obtain a compacted integral. In this article the vertical hydraulic drag force on regular tetrahedron is studied by indoor experiments, the relation of the vertical hydraulic drag coefficient and the vertical velocity is proposed. And the max vertical speeds of different materials are deduced. The result is helpful to compute the movement of regular tetrahedron in water and estimate the impact effect on the groundwork.

Experimental Study on the Flow Mitigation Characteristic of Sub-Water Permeable Spur Dike

2014 ◽  
Vol 926-930 ◽  
pp. 565-570
Author(s):  
Cheng Tao Huang
Keyword(s):  
Experimental Study ◽  
Drag Force ◽  
Fundamental Theory ◽  
Generalized Model ◽  
Spur Dike ◽  
Hydraulic Condition ◽  
Flume Tests ◽  
Permeability Characteristic ◽  
Lower Capacity

Methodology to evaluate the permeability characteristic of porous spur dike based on the fundamental theory of permeability is established. The series of flume tests were carried out and the permeability characteristic of porous spur dike was studied through testing of the proposed generalized model. Results indicate that for the porous spur dike with lower capacity of permeability, the generated resisting force when water goes through the spur dike can be divided into the drag force and the permeability force. Given the specific hydraulic condition and pattern of spur dike, the permeability force cannot be ignored, thus the porous spur dike with some permeable capacity can more effectively block the water in-flow compared with solid revetments.

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