Improvement of Operations and Maintenance Techniques Research Program: ChannelMaintenance by Training Structures: Guidance for Numerical Model Mesh Development

摘要

Training structures used to control channel currents and sedimentation, which inthe past were designed by rules of thumb, are now frequently the subject of numerical model investigations. The precision and stability of numerical models representing the shallow-water equations and transport generally are strongly influenced by the nature of the computational mesh upon which the calculations take place. This condition is amplified by the presence of man-made structures in the flow. It is therefore imperative that mesh development in the vicinity of these structures be guided so that accurate and reliable shoaling predictions result. This report uses a series of simple linear model equations applied in a finite element framework to develop guidance for the minimum mesh expansion rate, orientation, skewness, oscillation suppression, and bathymetric effects. While this effort was aimed at the TABS-2 modeling system, the findings are generally applicable to other finite element and finite difference models. Appendix A discusses the elimination of oscillations in the TABS-2 program. (Author) (kr)