Dam break flow benchmarks: quo vadis?

SPH has widened the scope of simulations of dam-break flows beyond the primary focus on impact loads. The flow complexity – involving boundary layers, air phase, surface tension, bubble and droplet formation, nonstationary, inhomogeneous and anisotropic turbulence – still imposes a piecemeal modelling approach to both two- and three-dimensional studies.

Here, two-dimensional simulations provide fresh insights into the capability of SPH to reproduce vortical and acoustic features after increasing the sole spatial resolution.

A dam-break flow on a dry floor and impacting a vertical wall has been resolved up to Re eff = 256,000. The array of spatial resolutions d/∆x = 800, 1600, 3200, 6400 shows the emergence by nonlinearity of progressively smaller flow scales. Fluid particles can populate the viscous sublayer and resolve boundary layer separations.

Also, in the stages of chaotic motion, the intricate soundscape of acoustic waves and pulses supported by the weakly compressible fluid is resolved cleanly. The frequency bands in the pattern-bearing spectra of pressure signals help diagnose both causal and spurious flow events occurred during a simulation. The efficacy of density diffusion and viscosity in abating disturbances below the scale of the kernel diameter is apparent.

Experiments are needed to address all flow stages and validate highly resolved 2D and 3D simulations of dam breaks. The available measurements do not cover the agitated stages, while pressure loads regard only the impingement stages. The configuration of new apparatuses could be optimized for a high return of relevant detail from the compute elements (SPH particles), so that simulations can produce densely informative datasets.