Numerical Simulation and Experimental Study of the Effects of Disposal Space on the Flow Field Around the Combined Three-Tube Reefs

The artificial reefs placed on the seabed with different layouts and disposal spaces will produce variational flow field. The intensity and scale of the combined three-tube artificial reefs with different layouts at five Reynolds numbers(Re) are numerically investigated by use of the RNG k-ε turbulent model and SIMPLEC algorithm. A stationary no-slip boundary condition is used on the models and the bottoms, and the free surface is treated as a "moving wall" with zero shear force and the same velocity with inflow. In order to validate the simulation results, a particle image velocimetry(PIV) experiment is carried out to analyze the flow field. The numerical simulation results are consistent with the data obtained from experiment. The corresponding errors are all below 20%. Based on the validation, the effects of disposal space on flow field are simulated and analyzed. According to the simulation, in a parallel combination, a better artificial reef effect is obtained when the disposal space between two parallel reefs is 1.0L(L is the length of the combined three-tube reef model). In a vertical combination, when the disposal space between two vertical reefs is 1.0L to 2.0L, the artificial reef effect is better.