Experimental and numerical investigation of the internal kinetics of a surf-zone plunging breaker
Publication: Research - peer-review › Journal article – Annual report year: 2011
Over the last couple of decades both the qualitative and quantitative understanding of breaking waves
in the surf zone have greatly increased. This is due to the advances in experimental and numerical
techniques. However, few comparisons between these two different investigative techniques for surfzone
breaking waves have been reported.
In this study, a comparison is made between the experimental and numerical investigation of the
internal kinematics of a surf-zone plunging breaker. The full-field velocity measuring technique known
as Particle Image Velocimetry (PIV) is used in the experiments. In the hybrid numerical scheme, the main
model solves the Navier–Stokes equations using a Finite Volume method and the free-surface is simulated
using a Volume of Fluid (VOF) method. An important feature of this work is that, unlike in most other
comparisons between numerical and experimental results, the exact geometry of the physical wave flume
and the exact motion of the physical wavemaker are duplicated in the numerical wave tank. To achieve
this, an additional numerical model using a Boundary-Integral Method (BIM) is employed to generate the
input conditions for the Navier–Stokes solver.
Very good agreement was found for all comparisons: free-surface elevations, velocity vector maps,
velocity profiles and velocity-magnitude contours. However, some small discrepancies were observed. In
the free-surface elevation comparisons, a slight time lag was observed in the numerical results and it is
suggested that this was due to the small amount of smoothing applied in the BIM to enable it to continue
to supply input data to the Navier–Stokes solver well beyond the breaking of the wave. In addition,
some small differences were also found between the numerically predicted velocity distributions and
those measured in the experiments. These disagreements occurred mostly in the aerated region and it is
proposed that they could be caused by errors in the PIV velocity data due to air bubble effects. However,
they could also be attributed to the fact that no turbulence model is used in the numerical scheme and it
is these aerated areas where the turbulence levels are the highest.
| Original language | English |
|---|---|
| Journal | European Journal of Mechanics B - Fluids |
| Publication date | 2012 |
| Volume | 32 |
| Pages | 1-16 |
| ISSN | 0997-7546 |
| DOIs | |
| State | Published |
| Citations | Web of Science® Times Cited: 0 |
|---|
Keywords
- PIV, Particle image velocimetry, Breaking waves, Volume of fluid method, Navier–Stokes equations, Boundary-Integral Method
ID: 6499174