Research on the scour protection effectiveness of permeable conical scour protection devices made from wasted tires was conducted though experiments. A combination of physical model experiments and numerical simulations are employed to evaluate the scour mitigation performance of the protection devices under various porosities and slope angle. Numerical simulations were further used to clarify the hydrodynamic characteristics and undermining process around the pile under the influence of the protection devices. By solving the Navier-Stokes (N-S) equations, using the RNG k-ε turbulence model and the Meyer-Peter and Müller (MPM) sediment transport formula, the scour protection effectiveness and hydrodynamic modes of the devices were investigated at different slope angles.
Experimental results indicated that permeable conical tire structures provide effective protection against scour. As the porosity of the protection devices decreases, their permeability reduces, leading to a more pronounced scour mitigation effect. The slope angle has an influence on local scour, where an increase in the slope angle results in greater scour at the structural edges. However, within similar conical angle ranges, such as α<20°, 20°<α<40°, and α>40°, the scour development patterns are comparable, and also the similar hydrodynamics and turbulent kinetic energy.
The study innovatively examined the scour protection effectiveness of porous permeable scour protection devices, clarified their protective characteristics, and elucidated the hydrodynamic properties around the structures. These findings offer valuable guidance and reference for practical marine engineering applications.