Numerical prediction of hydrodynamic force acting on a natural stone in open-channel flows.

Keisuke Yoshida, Satoru Ushijima, Ryuji Tanaka, Nobu Miyagi, Shiro Maeno

Tuesday 30 june 2015

9:15 - 9:30h at Europe 1 & 2 (level 0)

Themes: (T) Water engineering, (ST) Computational methods

Parallel session: 4E. Engineering - Computational

This study examines a numerical method that accommodates hydrodynamic forces acting on natural stone in open-channel flows. Numerical accuracy was verified through comparison with experimentally obtained results. We conducted three experiments with a stone model made of reinforced plastic, adjusting the flow discharge in a straight rectangular open-channel with a flat bed. For those experiments, we measured not only the drag force and lift force, but also the vertical velocity distribution of streamwise flow approaching in front of the stone. Additionally, we conducted numerical simulations to evaluate the forces acting on the numerically modelled stone. We approximately generated the numerical stone using tetrahedron elements in terms of a stone shape, imitating the actual model stone. For the computation model, we considered the mechanical interactions between fluid motions and the modelled stone, which behaves as a rigid body. Results show that numerical data related to the hydrodynamic forces are consistent with the experimental measurements. Therefore, the validity of our computation method was demonstrated.