Secondary Sand Transport Mechanisms

A crucial point still to be established in the prediction of oil-gas-sand multiphase production and transfer system performance is the identification of relevant mechanisms describing sand particle transport. To resolve this issue, experimental investigations are made on the behaviour of suspended sand particles in simulated oil-gas-sand multiphase pipe flows paying attention to the time-averaged local and global sand velocity and holdup. Simultaneous measurements of the time-averaged local and global sand velocity are made by digital imaging technique for better understanding of the oil-gas-sand multiphase flow hydrodynamics and sand transport mechanisms. The results show flow regimes of the multiphase flows significantly influence sand transport in the pipeflow. The shape of the local and global sand particle velocity and holdup profiles are also strongly modified by flow regimes. Furthermore, the experimental results indicate that the transport effect of the suspended sand particle can be enhanced by operating the multiphase flows under slug flow conditions. It is concluded that a new mechanism based on bubble-particle interaction needs to be considered in the modelling of sand transport behaviour during oil-gas-sand multiphase production and transfer operations.

Download Full-text

Near-Bed Sand Transport Mechanisms under Waves— A Large-Scale Flume Experiment (Sistex99)

Coastal Engineering 2000 ◽

10.1061/40549(276)254 ◽

2001 ◽

Cited By ~ 3

Author(s):

Jan S. Ribberink ◽

C. Marjolein Dohmen-Janssen ◽

Daniel M. Hanes ◽

Steve R. McLean ◽

Chris Vincent

Keyword(s):

Large Scale ◽

Sand Transport ◽

Flume Experiment ◽

Transport Mechanisms

Download Full-text

SECONDARY SAND TRANSPORT MECHANISMS

Coastal Engineering Proceedings ◽

10.9753/icce.v17.68 ◽

1980 ◽

Vol 1 (17) ◽

pp. 68

Author(s):

A.W. Smith ◽

A.D. Gordon

Keyword(s):

Work Capacity ◽

Sand Transport ◽

Primary Process ◽

Transport Mechanisms ◽

Littoral Drift ◽

Transport Mode ◽

Primary Mechanism ◽

Beach Sediments ◽

Individual Contributions ◽

Hydraulic Processes

The basic concept of coastal littoral drift consisting of a "river" of sand driven by the direct alongshore component of oblique waves has long been considered as a basis for littoral transport equations. This concept however is highly simplified since the actual littoral drift on real beaches represents only the final result of the inter-action of dozens or perhaps hundreds of secondary hydraulic processes which continuously occur in Nature. On many Coasts littoral transport is taken to represent the primary mechanism of beach recession or build-up but many of the secondary mechanisms themselves are only partially understood and their individual contributions to the primary process largely unexplored. This paper therefore discusses some of these secondary processes and since offshore- onshore sediment transport is probably the most important of these a mechanism for this transport mode is suggested based upon the interaction between wave energy and a work capacity parameter for the beach sediments.

Download Full-text

Physical Properties of Isolated Perfused Renal Tubular Basement Membranes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100065997 ◽

1971 ◽

Vol 29 ◽

pp. 390-391

Author(s):

Jared Grantham ◽

Larry Welling

Keyword(s):

Basement Membrane ◽

Basement Membranes ◽

Transport Mechanisms ◽

Permeability Characteristics ◽

Peritubular Capillaries ◽

Strategic Location ◽

Tubular Lumen ◽

Glomerular Filtrate ◽

Urine Formation ◽

Renal Tubular

In the course of urine formation in mammalian kidneys over 90% of the glomerular filtrate moves from the tubular lumen into the peritubular capillaries by both active and passive transport mechanisms. In all of the morphologically distinct segments of the renal tubule, e.g. proximal tubule, loop of Henle and distal nephron, the tubular absorbate passes through a basement membrane which rests against the basilar surface of the epithelial cells. The basement membrane is in a strategic location to affect the geometry of the tubules and to influence the movement of tubular absorbate into the renal interstitium. In the present studies we have determined directly some of the mechanical and permeability characteristics of tubular basement membranes.

Download Full-text