Validation of the short time correlation analysis

Exact solutions of phase change are available only for a few numbers of simplified problems. In realistic case no analytical solutions are available. We present in this study an acoustic system, which can monitor the interface evolution over time. The medium used to model the porous medium is composed of stacking glass spheres whose diameters are fixed and large compared with the ultrasonic wavelength and whose spaces are filled with water. The domain is multi-target and induces speckle. The interface cannot be seen a priori. We developed a method based on correlation similar to the short time Fourier analysis in order to find the spatial interface position. The experimental method efficiency depends on several parameters: transducer frequency, acquisition frequency, windows width correlation and time step between two consecutive A lines. The result thus obtained shows that the interface can then be seen clearly