Hydrodynamic Performance Characteristics of Double Vertical Perforated Wall

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Hany Gomaa Ibrahim Ahmed, Andreas Andreas Schlenkhoff

Friday 3 july 2015

11:00 - 11:15h at Amazon (level 1)

Themes: (T) Water engineering, (ST) River and coastal engineering

Parallel session: 15E. Engineering - River

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Abstract: The present paper investigates the hydrodynamic performance characteristics of a pair of vertical perforated wall, which can be used as a permeable breakwater to protect the harbor and coastal areas. The proposed permeable breakwater model consists of a pair of identical vertical perforated walls with an impermeable upper and lower part, where the draft is a decimal multiple of the total depth. The middle part is permeable with a porosity of 50%. The second barrier is located at distances of 0.25, 0.5, 0.75 and 1.00 times of the wave length from the first one. For regular waves, using the Eigen function expansion method and the boundary condition at the breakwater, a semi-analytical model has been used to compute a wave transmission, reflection and energy dissipation coefficients. Extensive study using a numerical model (FLOW-3D, VOF) has been conducted to detect the influence of the chamber width and friction coefficient. The laboratory experiments have been performed to assess both of the numerical model and the semi-analytical. Comparison of the present numerical model with the numerical model of a single perforated wall has been conducted. The velocity and vortices have been plotted by FLOW-3D in behind, through the slots and front of the model. A good agreement between experimental results and both of the numerical and semi-analytical results has been obtained and the results indicate the applicability of the numerical and semi-analytical model to discover of the wave behavior through the vertical perforated walls.