Manuel Marcoux

Salt crystallisation at the surface of a heterogeneous porous medium

Evaporation of saline solutions from a porous medium often leads to the precipitation of salt at the surface of the porous medium. It is commonly observed that the crystallized salt does not form everywhere at the porous medium surface but only at some specific locations. To explain this phenomenon, we consider efflorescence formation at the surface of a saturated heterogeneous porous column (finer porous medium in coarse porous medium background) in the wicking situation. We study the impact of permeability and porosity contrasts on the efflorescence formation location from a simple visualisation experiment and Darcys scale numerical simulations. We show that the porosity is the most sensitive parameter for our experiment and that efflorescence forms at the surface of the medium of lower porosity. A simple efflorescence growth model is then used to explain why the efflorescence continues to grow at the surface of the lower porosity medium without spreading over the adjacent surface of the greater porosity medium.

Effect and Propagation of Water Level Fluctuations in a Sloping Sandy Beach - Unsaturated Porous Media II

In coastal processes, the strong water movements due to short periodic waves (such as sea swell) can induce irregular water level fluctuations in the swash zone and within the sandy beach. The measured water level fluctuations with very complex entry water level fluctuations in a wave canal with a sloping sandy beach were analyzed by using 7 capacitive sensors. Numerical simulations have also been implemented in order to complement the experimental water level signal analyses. In this paper, a numerical test of single harmonic wave (long run) with same computational domain and porous media properties as the experiment is conducted to understand the effect and propagation of the water level fluctuations in the unsaturated porous media. The key coupling parameter of the macro (sea water) porous and micro (sloping sandy beach) porous media in the Richards equation model is further identified by this numerical test, which is the basis to simulate and explain the complex experimental results.

Effect and propagation of water level fluctuations in a sloping sandy beach—Unsaturated porous media

In coastal processes, the strong water movements due to short periodic waves (such as sea swell) can induce irregular water level fluctuations in the swash zone and within the sandy beach. The measured water level fluctuations with very complex entry water level fluctuations in a wave canal with a sloping sandy beach were analyzed by using 7 capacitive sensors. Numerical simulations have also been implemented in order to complement the experimental water level signal analyses. In this paper, numerical test of single harmonic wave with same computational domain and porous media properties as the experiment is conducted to understand the effect and propagation of the water level fluctuations in the unsaturated porous media. The key coupling parameter of the macro (sea water) porous and micro (sloping sandy beach) porous media in the Richards equation model is identified by the numerical test of single harmonic wave, which is the basis to simulate the complex numerical simulation with experimental boundary conditions.