Estimation of contact angle of soil water interface using Molecular Dynamics Simulations
Mohmad Mohsin Thakur
Department of Civil & Environmental Engineering, University of Tennessee
This page shows visualizations of contact angle between alpha quartz and water. These structures were created by Mohmad Mohsin Thakur.
The numerical modelling of multiphase flow in porous media requires contact angle as input parameter. The wettability and capillary suction in the pore networks of granular materials is strongly influenced by contact angle. alpha quartz is the most common mineral found in majority of sands. In present study, contact angle of alpha quartz and water is determined in Molecular Dynamics framework using a CLAYFF force field. The simulations were carried out in NVT ensemble at 300K for 3ns with periodic boundary conditions in x, y directions and fixed boundary condition in z direction (normal to the mineral slab). The domain size was about 400x20x200 Å3 with soil mineral slab size equal to 400x20x30 Å3 and water cuboid equal to about 60x14x60 Å3. Lennard Jones was used to describe the short-range potentials whereas long range potentials were accounted indirectly using Fourier based Ewald simulation method known as Particle-Particle, Particle-Mesh (PPPM) method. Contact angle was measured 59° from the time average density profile.1
Interactive Structures
Color Legend:
- grey + red = Alpha quartz
- yellowish orange = water
References
1.. Cygan, R., Liang, J., & Kalinichev, A. (2004). Molecular Models of Hydroxide, Oxyhydroxide, and Clay Phases and the Development of a General Force Field. J. Phys. Chem. B 2004, 108,1255-1266
posted: April 2018.
updated: April 2018.