In the paper; M. Davis, Köhler, H.J. and Koenders, M. A., 2006, “Unsaturated subsoil erosion protection in turbulent flow conditions”, Journal of Hydraulic Research; flow is considered over an obstacle placed on a coarse gravel layer that covers a sand layer. The pressure distribution as a function of position and time is obtained for partially saturated conditions in the subsoil. The flow in the open water and coarse layer is calculated using a lattice Boltzmann technique; the pressure in the subsoil is evaluated by means of an analytical solution using the lattice Boltzmann simulation as boundary condition. The results demonstrate where the greatest risk of damage to the subsoil may be located. In this part you may find some of figures in colours and animations of this work.
This is a snapshot of the flow lines as a function of the position for the case of flow over an obstacle. The streamlines for the fluid flow over the coarse layer, which covers the subsoil (brown area) with a 900 × 300 grid size, after 80,000 time steps. A high porosity is used here (n=0.4) to illuminate the paths of the streamlines.
This is a figure of a sequence of excess pore pressure profiles for times. Direction of flow is the x-axis, y-axis is depth of subsoil and p (Pa) is the pressure inside the subsoil.
Animation of the pressure in the subsoil