Reported measurements of seabed scattering are largely confined to relatively low frequencies, up to 300 kHz, see, e.g., [Jackson and Richardson] and references therein. Still higher frequencies, up to a few megahertz, are used in seafloor imagery (e.g., in pencil-beam sonars), particularly to observe dynamic processes at the seafloor in shallow water. From the physics of sound-sediment interac...

In this study, the hydrodynamic forces acting on the seabed around the pipeline in unidirectional ocean currents have been investigated numerically. Two types of seabed are considered, i.e., plane and distorted seabed. The influences of gap between pipeline and seabed on the distribution of forces along the seabed are studied in detail. Computational results show that the pressure at the upstre...

Iron ore and coal are the two major important raw materials being used in Iron making industries. Usually ore fines containing around 5% Alumina are rejected due to higher proportion of alumina. Therefore, a technology or process which may reduce the alumina content by 2% by beneficiation process will be highly attractive . In addition fine coals with ash content is used nearly 12% is directly ...

Abstract The dynamics of the installation process marine risers subjected to shoal/deep seawater is studied. riser assumed be a cantilevered Euler‒Bernoulli beam. upper end clamped on vessel or drilling platform. lower connected Blowout Preventer Stack (BOPs) and Lower Marine Risers Package (LMRP). lateral fluid forces induced by sea wave current are introduced into governing equations motion. ...

Two-interconnected fluidized bed systems are widely used in various processes such as Fisher-Tropsch, hot gas desulfurization, CO2 capture-regeneration with dry sorbent, chemical-looping combustion, sorption enhanced steam methane reforming, chemical-looping hydrogen generation system, and so on. However, most of two-interconnected fluidized beds systems require riser and/or pneumatic transport...

With high international oil price, the exhaustion of onshore resources and declination of oil and gas production in shallow sea, deep water has become the important succeeding area of worldwide oil and gas. During deepwater oil and gas development, riser must be used to isolate seawater, circulate drilling fluid, and compensate the heaving movements of the string and so on. However, with the op...

The aim of the research was to summarize a mathematical model of bow and arrow interaction in the vertical plane and to develop an appropriated computer model. A bow was modeled as a non-deformed riser and hinged to it two nondeformed limbs with Archimedean springs. Their stiffness as well, as an elasticity of a string was taken into account in a linear approach. An asymmetric bow scheme was co...

The vortex-induced vibration (VIV) of flexible risers is a complex fluid–structure interaction (FSI) phenomenon. In this study, we conducted numerical simulation method based on the slicing to study deep-sea with different slenderness ratios and uniform flow velocities. combines finite element model riser structure two-dimensional field slices solved by Fluent solver. was realized self-compiled...

An experiment was conducted to obtain data of pressure drop in riser tubes of liquid-solid circulating fluidized beds. In the experiment, 2 kinds of riser tube having a diameter of 24mm and 36mm were used. Tested particles were of glass and ceramics, and their diameter range was from 2.10 to 4.95mm. Water at ambient conditions was used as the fluidizing fluid. Pressure drop in riser tubes was m...