| Budget Amount *help |
¥6,100,000 (Direct Cost: ¥6,100,000)
Fiscal Year 1994: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1993: ¥4,800,000 (Direct Cost: ¥4,800,000)
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| Research Abstract |
The purpose of this study is to develop versatile, reliable numerical models for perdicting water quality in coastal and estuarine waters that depends heavily on baroclinic effects due to difference in salinity and/or water temperature. The flow in such waters is charactreristically categorized into three ; one-dimensional well-mixed flow, vertically two-dimensional stratified flow, three-dimensional stratified flow (in which horizontally two-dimensional well-mixed flow is included). The model for each category is built by coupling time-dependent spatially distributed flow in variable density field with water quality dynamics. The fruitful results obtained through this study are summarized as follows.
1.Flow models of high versatility, applicable to variable density field, were newly developed for the respective categories by employing the finite element method, and their numerical properties (stability, accuracy (mainly by rig-testing) and solution efficiency) were investigated.
2.For o
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ne-dimensional and three-dimensional problems, finite element water quality models were developed based on the convection-dispersion equation that describes variation of the water quality substances. By coupling the water quality model with the flow model, water quality prediction models, far refined than the conventional box models, were built.
3.For vertically two-dimensional problem, it was shown that the flow model was capable of being used for investigating vertical movement, stagnation and concentration of plankton, and therefore useful for understanding the mechanics of red-tide generation.
4.For future perspective of the study, a primary simulation model for biological system was developed and its basic numerical properties were tested. In addition, a water quality control model for rivers was proposed and its validity was demonstrated.
As the follow-up study, it is necessary to further investigate solution reproducibility of the models developed, and to discuss the methodology for estimation and identification of the unknown parameters involved. Less
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