Interaction of waves and a permeable structure is an attractive subject to coastal engineer. In present study, a new concept slit caisson breakwater is proposed, which has embedded channels for fluid resonance in the channel. When the amplified flow is passing through the slit plate, the incident wave energy is dissipated by flow separations. In order to evaluate wave energy dissipation performance of the breakwater, this study has focused on the wave reflection from the breakwater by using numerical simulation and hydraulic model test. The numerical experiment was carried out by Galerkin’s finite element model based on the linear potential theory, and the hydraulic model test was performed in a two-dimensional wave flume at KIOST. Comparison of the numerical results with hydraulic model test results shows proper agreement over wide wave periods. The performance of slit caisson breakwater with the embedded resonant channels was tested with various design of the embedded channel. This breakwater has advantages compared with conventional slit wall caisson breakwater. First, the channel design to control the target wave condition is easy and applicable to long wave periods for dissipating wave energy. Second, this breakwater has structural safety of slit members because the members are not exposed to impact load at near free surface, directly. When the incident wave period and natural period of water column in the channel were matched, the considerable wave energy dissipation was occurred. From this reason, the wave load acting on the breakwater is decreased by wave energy dissipation. The wave reflection characteristics were affected by the porosity of slit plate, the channel width, and the number of channels. Therefore, this breakwater is expected to economical and efficient coastal structures.CHAPTER 1 INTRODUCTIONS 1
1.1 Research Background 1
1.2 Literature Survey 2
1.3 Research Objectives and Scope 4
CHAPTER 2 THEORETICAL FORMULATION 6
2.1 Boundary Value Problem 6
2.2 Fluid Domain 8
2.3 Energy Dissipation at Slit Plate 11
2.4 Motion of Fluid in Channel 15
CHAPTER 3 FINITE ELEMENT FORMULATION 17
3.1 Genaral 17
3.2 Discretization of Fluid Domain 17
3.2.1 Finite Element Region 20
3.2.2 Infinite Element Region 23
3.3 Formulation of the Model 26
CHAPTER 4 NUMERICAL RESULTS AND DISCUSSIONS 27
4.1 General 27
4.2 Embedded Single Case 31
4.2.1 Influence of depth of the channel inlet 31
4.2.2 Influence of the channel width 41
4.3 Embedded Multi-Channels Case 53
4.3.1 Comparison of double and single embedded channel 53
4.3.2 Comparison of triple and single embedded channel 61
4.4 Comparison with other research 69
CHAPTER 5 HYDRAULIC MODEL TEST 71
5.1 General 71
5.2 Wave Flume 71
5.3 Model Set-up 72
5.4 Experimental Analysis 78
5.4.1 Separation of Incident and Reflected Waves 78
5.4.2 Comparison of Numerical and Experiment Results 81
CHAPTER 6 CONCLUSIONS 88
6.1 Conclusions 88
6.2 Future Studies 91
REFERENCES 92
APPENDICES 9
