Design of eco blocks for protection of submerged pipeline
In order to protect coastal facilities mainly from wave and current actions, the self-locking eco blocks constituting elements of protecting shore structures against scouring were designed. These blocks are adapted to the sloping bottom, coastal dunes, and submerged coastal pipelines, counteracting the destructive and erosive impulse action. A series of laboratory experiments has been conducted to investigate the reflection of water waves over and against a train of protruded or submerged shore structures and compare the reflecting capabilities of incident waves including wave forces. In this study the hydraulic model experiment was conducted to identify the performance of newly designed water affinity eco blocks to keep the coast slope and bottom mound from scouring by reduction of the wave reflection and to convince stability of the block placement. Revised design of each block element was also tested for field conditions. From the result of experiments, the field applicability of the developed blocks and placement was discussed afterward.
OPTIMUM SIZE OF DISTORTED RIPPLE TRAIN FOR THE CONTROL OF CROSS-SHORE SEDIMENT TRANSORT
The Distorted Ripple Train System, which is aimed to control the crossshore sediment transport, is proposed. The concept and basic functions of the artificial ripple system are introduced in the study and a detailed discussion is given on the determination of the optimum size of the individual ripple which enhance the effect of control.
PHASE DEPENDENT ROUGHNESS CONTROL OF SAND MOVEMENT
Experiments with wave motion over asymmetrical "ripple-like" forms show that the difference between a net sand transport in a down-wave versus an up-wave direction is related to a subtle phase dependent mechanism associated with the intensity of vortex formation in the lee of the form. Artificial roughness modules have been developed, consisting of arrays of asymmetrical forms resembling natural ripples. The asymmetry of the forms causes an intense vortex to form in the lee of the steep face. This vortex traps and suspends sediment, which when the orbital motion reverses its phase, is lifted above the roughness element and carried in the new direction. Thus, the direction of the net sand transport is dependent upon the relation between the steep face of the roughness element and the phase of the orbital velocity; the net transport being in the direction of the orbital velocity that is out-of-phase with the maximum vortex formation.