An experimental study is made of the steady-state natural convection induced by a heat source of finite width (30 cm long × 15cm wide) located at the center of bottom surface of a model reservoir (140cm long × 15cm high). The top surface is permeable and all other surfaces impermeable. The four side surfaces and the bottom surface are thermally insulated except the heat source. Correlating equations of the Rayleigh number versus the total discharge and the mean heat flux transported by water through the top surface are deduced by means of a dimensional analysis. The patterns of convective current are estimated from the temperature within the porous medium and the distribution of discharges at each portion of the top surface.
The two of several difficulties in the ground-based infrared remote sensing in geothermal fields are studied theoretically. A technique filtering natural steam standing between a target area and a radiometer in geothermal fields is developed firstly by means of a simplified model.The model consists of the broad and upright target area and a plume of steam, both having uniform surface temperatures, respectively. The ratio of different fractional amounts of a plume of steam within the two adjacent or partially overlapping fields of view is used to derive an explicit formula estimating the surface temperature on a part of the target area hidden by natural steam. Next, the absorptive and emissive effects of atmospheric water vapor on the remotely sensed surface temperatures of the target area are expressed numerically in terms of the air temperature, the relative humidity and the height of the observing site as well as the observing distance.