||Laboratory experiments and neural network method have been widely applied to the research on wave run-up and overtopping. The former is often costly and time consuming, as well as subject to scale effect; while the latter requires better training data for achieving good results. Unlike empirical methods established in the past, this research project adopts a theoretical framework integrated with a numerical method, Flow 3D, and focuses on modeling wave overtopping rate on a sloping and bermed seawall with several different dissipators. The front slopes investigated are within the range of 1:0.5~1:8(16 cases in all), for a sloping seawall with the Link blocks in single or double layers, ripraps in single or double layers and a submerged detached breakwater with 6 cases of top width in 6 cases of top depth and 8 types of water depth for submerged breakwater.|
The outcome of verifying experimental results using Flow 3D is presented in two aspects: (1) Qualitatively, using difference of wave overtopping rate between Flow 3D modeling and CLAH data base within about 5 %; and difference of wave overtopping rate between Flow 3D results and laboratory experiments conducted in NSYSU about 19 %, thus indicating the model results of Flow 3D agree well with the results of laboratory experiments; (2) Quantitatively, using the waveforms of model results from Flow 3D and the experimental results. Based on these comparisons, it infers that Flow 3D can be adopted and applied to the present project.
Wave overtopping modeling using Flow 3D on a sloping seawall with various wave absorbing arrangements yield the following findings: (1) The slope of a smooth seawall should be within 1:4.5~1:8; (2) Link blocks on entire fronting slope are better than blocks on the toe only; and double layers of blocks are effective for reducing maximum wave energy; (3) To reduce wave energy on ripraps, the integral roughness should be taken into account; (4) On overall performance using different placements of dissipators for reducing overtopping, seawall with slope 1:8 with 5 tons of Link blocks in double layers on the entire front slope is the best; (5) Amongst the 4 different wave steepness tested for wave overtopping rate Q, it is found that Q reduces as SH/HS and SB/HS increase (SH: height of seawall; HS: wave height; SB: crown width), as well as deeper location for a submerged breakwater.