Abbas Khayyer - M.Sc. Student, College of Civil Engineering, Iran University of Science and Technology
Abbas Yeganeh-Bakhtiary - Assistant Professor, College of Civil Engineering, Iran University of Science and Technology,
Abbas Ghaheri - Associate Professor, College of Civil Engineering, Iran University of Science and Technology
Toshiyuki Asano - Professor, Department of Ocean & Civil Engineering, Kagoshima University, Kagoshima, Japan

A two-dimensional numerical model has been developed to study wave transformation in surf zone. A free surface VOF (Volume Of Fluid) model in conjunction with a turbulence closure model have been employed in a RANS solver to study shoaling, breaking and overturning of waves inside surf zone. Approximations to the governing equations are acquired by use of Finite Difference Method. Two different types of breakers, namely plunging and surging breakers, are studied. Breaking types and characteristics of waves at the breaking points are well compared to the results of an experimentally validated wave model based on potential flow equations. Discussions are made on the velocity field during breaking process. At the breaking point, where the wave front face becomes nearly vertical, the crest velocity is found to be equal to the breaking wave speed. The maximum particle velocity at the breaking instant is observed to occur near the free surface in the vicinity of wave front with a value around 27% above the crest velocity. All mentioned conclusions are well supported by experimental and other numerical studies.

wave transformation, wave breaking, breaking criterion, breaking index, velocity field, Volume Of Fluid (VOF) method