Recently geoelectrical monitoring by subsurface visualization has become to contribute to the earth environmental resources problems such as groundwater resource cycling delineation, earth and water contamination, detection of rock fractures in active geothermal energy extraction system, mining with faults and groundwater effects, nuclear waste disposal, and environment/ground improvement by In-Situ Virtrification (ISV) technology. In this paper, a simple model study on resistivity monitoring for the effective utilization of earth resources and environmental system design has been investigated by the subsurface visualization pseudo-effects which are sometimes very useful as same as the high accuracy inverted resistivity solutions by the finite element 2D-3D algorithm. Key words: Subsurface visualized information, Inhomogeneous monitoring, Earth resources and Environmental system design, Enviromental geophysical engineering, Pseudo-effects.
Our previous study indicated that infrared radiometry was suitable for nondestructive testing of joints in divertor structures for a fusion reactor. Radiation temperature difference between an unbrazed tile and a brazed one was clearly observed when the model divertor was heated using a halogen lamp. This paper describes the influence of three different heating methods on thermal images of model divertor that contain improperly bonded are as in the joint, in order to obtain information about the most appropriate heating method. Model divertors, which consist of carbon-carbon(C/C) composite tiles brazed to a Cu heat sink with different brazed areas, were heated using the halogen lamp, high temperature gas, or warm water. It was confirmed that the temperature difference between brazed and unbrazed areas could be detected by infrared radiometry and that the smallest unbrazed area was detected when warm water was used.
The X-shaped intersecting flow is shown in staggered bundles of cylinders. The staggered arrangement is more effective from the heat transfer and fluid control standpoint. Experiments using a particle tracing method were performed to visualize the flow in the staggered bundles. In order to determine the flow mechanism, the velocity and pressure variations in the flow field were measured using a two-dimensional laser Doppler velocimetry and a piezometer, respectively. It is disclosed that the flow characteristics depend on the aspect ratio, the diagonal distance and the centrifugal force generated by flowing around each cylinder. The characteristics of hydraulic resistance and dominant frequency for power spectrum in tube banks are also determined.
Heat transfer by natural convection and radiation in participating fluids enclosed in a square enclosure is numerically simulated. The continuity, momentum and energy equations are solved by the control volume method while the thermal radiative transfer is analyzed by the Monte Carlo simulation. In this study the WSGG (Weighted-Sum-of-Gray-Gases) model is incorporated for handling the complicated radiative properties of non-gray gas with temperature and wavelength dependency. All variables such as U, V, and T are solved each time the radiative heat flux is updated. Both the nongray gas analysis and the conventional gray gas assumption based analysis are carried out. As the result, the influences of thermal radiation on the flow and temperature field are found significant. In areas close to the insulated walls, unstable temperature stratification is observed. The mechanism for this distinct phenomenon is discussed. It is found that the non-gray gas solutions differ widely from the conventional gray gas results which overestimate the flow strength and underestimate the unstable temperature stratification.
Observational study is carried out to clarify the behavior of vortices formed in the free shear layer of pulsating jet, and to compare that of a steady jet. The flow is visualized by hydrogen bubble method, and pulsating flow is generated using Scotch yoke mechanism. Obtained results are as follows: The frequency of vortex formation in the shear layer agrees with that of pulsating velocity at the nozzle exit regardless of the amplitude ratio of pulsating velocity. The contraction width of jets decreased as the amplitude ratio increased. The formation and growth of vortices in the case of pulsating jets are occurred at the upstream position than those in the case of a steady jet.