| Summary: | 碩士 === 國立中興大學 === 土木工程學系 === 88 === Using the Finite Element Method, this research simulates and solves the two-dimensional, steady, incompressible, and viscous turbulence flow. First, it changes thedepth-averaged governing equation into the finite element model so as to proceed the operation of numerical simulation. In the process of the operation, arithmetic errors are made because of the size differences among elements and also because of the unfitness between the positions and distributions
of nodes and the need of local accuracy. Then, using the definition of the root-mean-square norm to estimate the errors, produced in the process of operation, of each element, and also to do the mesh relocation according to the errors. R-refinement is adopted to do the mesh relocation. In other words, to re-distribute the size and the location of each element without adding the number of elements, raising the degree of freedom of the shape function, or the order of the complete polynomial of it, so as to get the best mesh relocation. In the process of relocation, do control the angle of the mesh to avoid the results of bad shapes.
Centered on the groin flow, this research uses uniform mesh combined with the automatic adaptive refinement technique and non-uniform mesh to do the operation so as to compare the two different ways of mesh distribution and also the results of simulation of the mesh relocation. Then, compare the location of velocity in the flow according to the studies made before to get the identical tendency. The final step is to discuss the influences made by the Froude number,
the constriction rate, the turbulent eddy viscosity, and the manning n in the recirculation region of groin.
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