Large-wave simulation of microscale breaking waves induced by a free-surface drift layer

摘要: Abstract The unsteady evolution of microscale breaking waves induced by a free-surface drift layer is studied performing large-wave simulation (LWS) the corresponding flow. initial flow condition superposition gravity wave and surface layer. Their interaction models propagation in ocean under influence wind forcing. governing Euler equations are filtered according to LWS formulation solved numerically spectral method for spatial discretization fractional time-step scheme time advancement. Lengths rendered dimensionless drift-layer thickness velocities gravity-wave celerity. depends on Froude (gravity), Fr, Weber (surface tension), We, numbers, through dynamic condition, velocity, q, height, H∘, which sets breaker intensity. Several cases considered Fr = 3.6, We = ∞, 10 5, q = 0.3, H∘ = 5.2, 6.5 7.8. results, associated with breakers, focus profile subsurface characteristics. Decreasing number results reduction crest elevation, growth bulge size lowering toe while increasing height stronger breakers increase tension influence. acquires its steepest slope at spilling face breaker, upstream toe, start breaking; this value not affected tension. fluid streamwise velocity maximum magnitude during after occurrence slope. interval between two events equal about three quarters period weaker (H∘ = 5.2) decreases zero (H∘ = 7.8). becomes celerity C but smaller values finite decrease decreasing i.e., it 0.92C We = 5 H∘ = 5.2. speed crest, other hand, that larger than In all cases, post breaking, always much agreement experimental measurements. energy dissipation increases same maximum. Finally, vortex, disrupts vorticity field layer, formed region peak strength number. disruption weak strong ones.