Autonomous Underwater Vehicles (AUV’s) are considered as advanced classes of vehicles, capable of performing pre-established missions without physical communication with the ground or human assistance. The research a...Autonomous Underwater Vehicles (AUV’s) are considered as advanced classes of vehicles, capable of performing pre-established missions without physical communication with the ground or human assistance. The research and development of this type of vehicles have been motivated, due to its excellent characteristics, ideal to the military, scientific and industrial sectors. Thus, the objective of this paper is to study fluid flow behavior past over AUV’s, without and with control surfaces (rudders), by Computational Fluid-Dynamics (CFD), aiming to obtain information about the impact of the operating depth and control surfaces on the vehicle's hydrodynamics, in order to help researchers and designers of this class of vehicles. Results of the drag coefficient, pressure, velocity and streamlines distribution around the vehicles are presented and analyzed.展开更多
The results of the spectral-correlation analysis of the fluid-dynamic (radon and hydrogen) data monitoring obtained in the seismically active region—on Kamchatka and in conditions of Russian platform where compared t...The results of the spectral-correlation analysis of the fluid-dynamic (radon and hydrogen) data monitoring obtained in the seismically active region—on Kamchatka and in conditions of Russian platform where compared to the results of the laser-deformometer measurements obtained on Caucasus. It allowed identify spectral components of the measured parameters, first of all, in the area of the lunar-solar tides. This identification have demonstrated the identical reaction of the mountain and platform regions to the global geodeformation processes of the tidal level and have shown the possibility of the measuring parameters response to the catastrophic events preparation processes. Really the prognostic effects in the investigated fields where indicated in periods of preparation and realization of the catastrophic earthquakes in Indian Ocean on December, 26, 2004 and on March, 28, 2005.展开更多
Measurement of temperature profiles of gas-solid two-phase flow at different heights in commercial-scale circulating fluidized bed （CFB） boilers was carried out. Experimental results showed that the thickness of the...Measurement of temperature profiles of gas-solid two-phase flow at different heights in commercial-scale circulating fluidized bed （CFB） boilers was carried out. Experimental results showed that the thickness of thermal boundary layer was generally independent of the distance from the air distributor, except when close to the riser outlet. Through analysis of flow and combustion characteristics in the riser, it was found that the main reasons for the phenomena were： 1 ） the hydrodynamic boundary layer was thinner than the thermal layer and hardly changed along the CFB boiler height, and 2） both radial and axial mass and heat exchanges were strong in the CFB boiler. Numerical simulation of gas flow in the outlet zone confirmed that the distribution of the thermal boundary layer was dominated by the flow field characteristics.展开更多
基金Brazilian Research Agencies CNPq,CAPES and FINEP for supporting this work
文摘Autonomous Underwater Vehicles (AUV’s) are considered as advanced classes of vehicles, capable of performing pre-established missions without physical communication with the ground or human assistance. The research and development of this type of vehicles have been motivated, due to its excellent characteristics, ideal to the military, scientific and industrial sectors. Thus, the objective of this paper is to study fluid flow behavior past over AUV’s, without and with control surfaces (rudders), by Computational Fluid-Dynamics (CFD), aiming to obtain information about the impact of the operating depth and control surfaces on the vehicle's hydrodynamics, in order to help researchers and designers of this class of vehicles. Results of the drag coefficient, pressure, velocity and streamlines distribution around the vehicles are presented and analyzed.
文摘The results of the spectral-correlation analysis of the fluid-dynamic (radon and hydrogen) data monitoring obtained in the seismically active region—on Kamchatka and in conditions of Russian platform where compared to the results of the laser-deformometer measurements obtained on Caucasus. It allowed identify spectral components of the measured parameters, first of all, in the area of the lunar-solar tides. This identification have demonstrated the identical reaction of the mountain and platform regions to the global geodeformation processes of the tidal level and have shown the possibility of the measuring parameters response to the catastrophic events preparation processes. Really the prognostic effects in the investigated fields where indicated in periods of preparation and realization of the catastrophic earthquakes in Indian Ocean on December, 26, 2004 and on March, 28, 2005.
文摘Measurement of temperature profiles of gas-solid two-phase flow at different heights in commercial-scale circulating fluidized bed （CFB） boilers was carried out. Experimental results showed that the thickness of thermal boundary layer was generally independent of the distance from the air distributor, except when close to the riser outlet. Through analysis of flow and combustion characteristics in the riser, it was found that the main reasons for the phenomena were： 1 ） the hydrodynamic boundary layer was thinner than the thermal layer and hardly changed along the CFB boiler height, and 2） both radial and axial mass and heat exchanges were strong in the CFB boiler. Numerical simulation of gas flow in the outlet zone confirmed that the distribution of the thermal boundary layer was dominated by the flow field characteristics.
