الفهرس 
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Abstract
There are many types of coastal protection structures such as
nourishment, jetties, seawalls, groins and breakwaters. In this study a
breakwater which consists of caisson supported on piles system and thin
plates suspended on the supporting piles seaward and shoreward was
investigated using Numerical model(FLOW-3D) and a physical model.
For the numerical model a Computational Fluid Dynamics (CFD)
has been implemented to test the hydrodynamics performance of the
suggested breakwater. The breakwaters system in numerical model was
placed in the grids with Fractional Area Volume Obstacle Representation
(FA VOR) method.
The efficiency of the breakwater was presented as a function of the
wave transmission, reflection and energy dissipation coefficients. The
breakwater characteristics and waves parameters were investigated. It
was found that, the transmission coefficient (k.) decreases with increasing the relative caisson draft (D I/h), the relative plate depth (D2/h and D3/h), the relative breakwater width (B/h), the distance between piles (S) and
piles diameters (d) and with decreasing the piles gap-diameter ratio (G/d).
The study shows that values less than 0.25 for k, are possible when
DJ/h20.5 and also when D2/h,D3/h20A at DJ/h=O.1. The reflection
coefficient (k.) values are within the range between 30 to •. 0 % for all
studied models. The proposed breakwater dissipates about 10 to ’\. % of
the incident wave energy.