Small Scale Physical Measurement of Wave Overtopping For Different Shore Protection Structures

Abstract

Article History: Received: 4 Jun 2019 Accepted: 5 Sep. 2019 Using artificial constructions is one of the most important ways to protect shores against wave actions and the consequent erosion. Due to costly nature of large scale marine projects, it is considered an efficient approach to study small scale model of the structure for simulation of sea conditions, measurement of hydraulic parameters and wave-structure interactions. In present research, construction of a small wave flume has been reported. Water up to 15 cm deep is filled in the flume and a DC motor directly rotates a flap in oscillations as a result of which regular waves of less than 10 cm height are produced. Wave lengths are around one meter, and wave periods are about one second. High quality fast images were analyzed in order to characterize the waves. Test runs were performed with different combinations of the wave parameters and the water depth, on five different revetments including: vertical seawall, simple slope, stepped slope, curved and recurved. Wave discharge with the aid of a small reserve tank at the far end of flume was measured. Results show that the recurved structure for most of the test cases reduce the wave overtopping to zero. The stepped slope has an efficient performance in dissipating the wave energy and reducing the wave run-up and overtopping. Simple slope recorded maximum discharge. Curved structure creates a water column of high speed vertical jet, and lastly the vertical seawall undergoes severe wave impact. Quantitative test results have been compared with well-known Owen’s formula for wave overtopping.