TY - JOUR
TI - Velocity difference changes between fluid and sand particles in boundary-layer and very near wake area
AU - Sha Sha
AU - Zhang Xiantang
AU - Wang Zhiang
AU - Liu Han
AU - Zhang Huiyao
JN - Thermal Science
PY - 2021
VL - 25
IS - 6
SP - 4217
EP - 4224
PT - Article
AB - Fluent simulates the water-sand flow around a cylinder. Monitoring lines are  set up at different positions in the cylindrical surface and the very near  wake area behind the cylinder, in order to explore the speed difference of  fluid and sand in the water-sand two-phase flow in the boundary-layer and  the very near wake area. The results show that the sand particles stay for  the longest time on the back of the cylindrical surface and in the very near  wake area, and a small part of the sand particles are sticky on the back of  the cylindrical pier. When the height of the cylinder is z/D ∈ (1.57, 3.14),  the turbulent flow on the cylindrical surface is fully developed. The  dynamic pressure of the flow field in the very near wake area be-hind the  cylinder fluctuates greatly, and the water-sand flow is extremely unstable.  At the monitoring position of the cylinder, there is a sudden decrease in  the velocity of the fluid, while the velocity of the sand particles changes  little and remains finally at about -0.02 m/s. The water-sand flow field  near the wall changes drastically, but the velocity change of sand particles  has obvious hysteresis compared with fluid. When leaving the near-wall  position but still in the cylindrical wake area (x/D ≤ 3), the changes in  the water-sand flow field are more intense and the velocity of the sand  particles is still slightly larger than the fluid velocity.