HYDRODYNAMIC PERFORMANCE CHARACTERISTICS OF SEMICIRCULAR BREAKWATER—WAVE RUN-UP AND RUN-DOWN

ABSTRACT

Breakwaters are structures protecting a shore area, harbor, anchorage, or a basin from the fury of ocean waves. They create calm waters and give protection for safe mooring, operating and handling of ships, and provide protection to harbor facilities. Semicircular breakwaters are becoming increasingly popular these days, as they have high stability against the action of waves. The paper explains the physical model studies to evaluate the wave run-up (R_d/H_i) and wave run-down (R_d/H_i) on semicircular breakwater model for various incident wave heights H, wave periods T, water depths d and spacing (S) to diameter (D) ratios of perforations (S/D). It is found that relative wave run-up increases with the increase in wave steepness (H_i/gT²) and relative run-down decreases with the increase in wave steepness. Relative wave run-up and wave run-down values increase with the increase in depth parameter (d/gT²). The relative run-up and run-down values decrease with increasing perforations (decreasing S/D values) in breakwater.

KEY WORDS:

• Semicircular breakwater
• Relative wave run-up
• Relative wave run-down
• Incident wave steepness
• Depth parameter
• Spacing to diameter ratio