Research objectives and content
Coastal Structures, like groins and mound breakwaters are buil to protect an area from the wind wave action. Generally speaking, they dissipate wave energy inducing wave breaking. However, depending on the type of reflective structure and of the incinent wave characteristics, part of the energy is returned to the sea under the Reflection Process. The interaction between the incident and the reflected wave trains develope complex wave patterns of diamond shape, enhancing the wave amplitude in certain points while reducing and others.
It is well known m the Engineering Practice, that coastal structures built on sandy coasts, may suffer scour erosion and enhance the sediment transport. Furthermore, toe erosion may induce the sliding failure modes of the bottom berm, of the main layer and of the whole breakwater. The location and extension where scouring occurs, is still undetermined and there are not well established engineering rules to face this problem. This proposal is related to the problem of sediment movement m front and around reflective structures. The final goal of the research is to provide sediment patterns and simple prevention techniques depending on the reflectivity of the structure and on the wave characteristics, including wave spectrum and incidence angle.
The Research Project includes the following main aims as the basis for the establishment of engineering rules to prevent scouring in front I and around coastal structures:
al. Analytical model of the wave scattering from a semi-infinite mound breakwaters on an horizontal bottom. a2. Radiation stress distribution a3. Mean flows inside and outside the breakwater. a3. Sediment Movement. a4. Preventive actions a5. Submerged structures and bars
Training content (objective, benefit and expected impact)
The objective of the Program is to tram the candidate in the field of the mean flows and related sediment transport, induced by wave transformation, reflection and dissipation inside a porous structure, joining a group which is leading the research in this area of knowledgment. The benefit should be mutual to the hosting group and to the candidate. To the group, because the candidate knows the theory of wave through porous media and the role played by the reflection wave train in the wave pattern in front of reflective structures To the candidate, because she will learn new techniques, approaches and methods from the hosting group, which will be very important to built her research schemes.
The goal of the research is to clarify the scouring problem induced by reflective structures and to propose simple techniques to reduce this important coastal engineering problem. Thus, it is expected that the proposed research, will contribute to decrease the number of breakwaters failed because of scour erosion, and to reduce the maintenance cost of the reflective coastal structures built m the future. Links with industry / industrial relevance (22)
Although the project is not linked to the industry, once the main patterns of scouring will be established, the candidate will joint constructors, in order to discuss different techniques and construction procedures to face the scouring problem.