Author(s): Yong G. Lai; Larry Weber
Linked Author(s): Larry J. Weber
Keywords: Wetting-drying simulation; Full 3D computation; Unsteady CFD
Abstract: Water flows in open channels and natural rivers are mostly unsteady in nature due to variation of flow discharge resulted from seasonal changes and controlled operation of hydraulic structures. The unsteadiness is important when there exist submerged islands immediately upstream or downstream of the hydraulic structures, and it is also particularly important when wetting-drying process is encountered due to events such as flooding. Despite its importance, however, unsteadiness has not been paid much attention in most projects involving fully three-dimensional computational fluid dynamic modeling. This paper is our first attempt to address the issue of unsteadiness in the context of fully three-dimensional numerical modeling without hydrostatic assumption. Particularly, effort is directed at the ability to simulate wetting-drying process in a reach of open channels where there exist islands or compound channels. The basic numerical method is presented first, and the wetting-drying algorithm is then proposed and developed. After a verification study with the developed code, a sample application is presented to demonstrate the numerical method.