Visualization of thermal fields in saturated porous media by the christiansen effect.

A quantitative optical method has been demonstrated for the study of two-dimensional thermal phenomena in saturated porous media, making possible the visualization of a certain number of isotherms as bright lines of different colors. A study of the characteristics of Christiansen filters has been carried out in order to determine the experimental conditions most favorable to the use of this method. Examples of its application are given relative to phenomena of natural convection.