Waves and Tidal Flat Ecosystems - Baba, Eiichi

. .

Résumé :
The authors explain the rewarding results from the interdisciplinary collaboration between an environmental study group working on coastal ecosystems and effects of oil spills and applied mathematicians modelling wave motion on sandy beaches. By using the unified Navier-Stokes equations with a Bingham fluid model for spilled oil, multi-phase flow analysis were made. Decomposition of spilled oil by bacteria was simulated as a chemical reaction, and the theoretical and numerical analysis suggested a countermeasure to help reduce stress on coastal ecosystems. The new understanding of how ecosystems both depend upon, and help to determine, the nature of the shoreline demonstrates promising ways to better assist and exploit the regenerative powers inherent in nature....

Sommaire:
1 What is a tidal flat?.- 1.1 Introduction.- 1.2 Function and structure of natural and man-made tidal flats.- 1.3 Key factors to determine a tidal flat characteristic.- 1.4 Fluid flow on a tidal flat.- 2 Effects of waves and tide on tidal flat ecosystems.- 2.1 Introduction.- 2.2 Method of experiments on internal flow in seabed.- 2.3 Role of wave and tide on seawater infiltration in sandy beach.- 2.4 Role of wave and tide on ecosystems in tidal flats.- 2.5 Concluding remarks.- 3 Unified model for wave breaking action.- 3.1 Introduction.- 3.2 Mathematical model.- 3.3 Unified model for two-phase flow with surface blocking effect.- 3.4 Numerical results.- 4 Oil pollution: human damages on hydraulic regime in sandy beach ecosystems.- 4.1 Introduction.- 4.2 Infiltration of stranded oils into sandy beach sediments by waves and tides.- 4.3 Effects of the penetrated oils into sandy beach sediments on seawater infiltration by waves.- 5 Theoretical study of oil pollution.- 5.1 Introduction.- 5.2 Behavior of spilled oil in the surfzone.- 5.3 Mathematical model.- 5.4 Unified model for three-phase flow with adhesion.- 5.5 Numerical results.- 6 Oil pollution: human damage on hydraulic regime and benthic communities in tidal flat ecosystems.- 6.1 Introduction.- 6.2 Penetration of stranded oils into tidal flat sediments by tides.- 6.3 Effects of the penetrated oils into tidal flat sediments on seawater infiltration by tides.- 6.4 Effects of oil spill on seawater infiltration and macrobenthic community in tidal flats.- 7 Decomposition mechanism of spilled oil by bacteria.- 7.1 Introduction.- 7.2 Notations.- 7.3 Characteristics of oil decomposition into water.- 7.4 Incompressibility condition for a total flow system.- 7.5 Biological contribution to satisfy reactivity condition.- 7.6 Unified model for three-phase flow with decomposition.- 7.7 Numerical results.- 8 Breaking waves and ecosystem dynamics.- 8.1 Introduction.- 8.2 Mathematical modeling.- 8.3 Coupling scheme between waves and ecosystem dynamics.- 8.4 Numerieal results.- 9 Methodologies for theoretical studies.- 9.1 Introduction.- 9.2 Mathematical methodologies.- 9.3 Numerical methodologies.