Non-hydrostatic computations of nearshore hydrodynamics

Caption : An Australian beach where surfers ignore the danger sign because in fact the rip current is very useful in taking their surfboards beyond the breaker zone Cover photograph by : Matthew Celia (2008) i Title : Acknowledgements This thesis concludes the M.Sc. Civil Engineering program at the Delft University of Technology. Writing this thesis was challenging, not only for the subject at hand, but also for the individual process one has to go through, which can feel quite lonely at times and requires a substantial amount of discipline. Numerical modelling can be very frustrating at times but can also be very satisfying and, if the chronological order of both experiences is in the same order as above, one usually forgets the frustrating part immediately. My experience of numerical modelling is therefore an experience I cherish and something that I regard as very useful for my future career. There are a number of people that I would like to thank for their guidance, help and support while writing this thesis. Firstly, I would like to thank my parents as they have always supported me in my studies and endeavors. Secondly, I would like to thank my girlfriend Sinéad who has always offered me positive encouragement. Finally, I would like to thank my supervisor Pieter Smit who helped me overcome the many obstacles I encountered while writing this thesis. I would also like to extend my gratitude to the other members of the graduating committee who provided me with constructive criticism and recommendations. To end, I would like to say that working on this thesis has given me a deeper insight into the career path I wish to take. Abstract The nearshore zone is an active zone that can be quite inhospitable to humans due to violent wave breaking and strong rip currents. Rip currents are shore normal jet-like currents that typically extend from near the shoreline out past the line of breaking waves. Observations have concluded that a rip current system generally consists of 4 parts. Part 1 is the shoreward mass transport due to the waves carrying water through the breaker zone in the direction of wave propagation. Part 2 is the movement of this water mass parallel to the coast known as a longshore current. Part 3 is the rip current itself, a seaward flow of water through a narrow rip channel. And part 4 is an …