Inclusion of an acoustic damper term in weakly-compressible SPH models

The proposed work describes a novel viscous term specifically conceived to reduce the amount of acoustic pressure waves in weakly-compressible SPH models. The above-mentioned term only acts on the acoustic component of the pressure field, which is generated as a consequence of liquid impacts and of the assumption that the fluid is weakly-compressible, whereas it leaves the incompressible-like component unchanged. In comparison to the existing regularizing terms in the SPH literature, this allows for noise-free simulations which are similar to simulations of incompressible flows, and, at the same time, it maintains the advantages of explicit schemes (i.e. scalability and easiness of parallelization). The proposed acoustic damper term converges to zero when the particle resolution increases, recovering the consistency with the Navier-Stokes equations. Numerical results demonstrate that this term is effective for flow simulations with different weakly-compressible SPH models.