SPH numerical investigation of the velocity field and vorticity generation within a hydrofoil-induced spilling breaker

摘要

In the present work, the velocity field and the vorticity generation in the spilling generated by a NACA 0024 hydrofoil were studied. SPH simulations were obtained by a pseudo-compressible XSPH scheme with pressure smoothing; both an algebraic mixing-length model and a two-equation model were used to represent turbulent stresses. Given the key role of vortical motions in the generation of the spilling breaker, the sources of vorticity were then examined in detail to confirm the interpretation of the mean flow vortical dynamics given in a paper by Dabiri and Gharib (J Fluid Mech 330: 113-139, [ 1997]). The high precision of the SPH model is confirmed through a comparison with experimental data. Experimental investigations were carried out by measuring the velocity field with a backscatter, two-component four-beam optic-fiber LDA system. The agreement between the numerical results and laboratory measurements in the wake region is satisfactory and allows the evaluation of the wave breaking efficiency of the device by a detailed analysis of the simulated flow field.