The numerical simulation of time dependent flow structures over water worked gravel

摘要

Our ability to numerically predict the interaction between time dependent fluid flow structures and complex topography has yet to be fully developed. This is largely the result of the problems of designing numerically stable meshes for use with complex topographies and that Reynolds averaged turbulence schemes are typically applied. This paper deals with the numerical simulation of time dependent flows over a water worked gravel. This is achieved by the development of a porosity algorithm for representing complex surface topography in a Cartesian framework and the application of Large Eddy Simulation. The numerical simulations reported in this paper show that there are two distinct scales of boundary influence upon the shallow flow and emphasizes that the measured flow variability at any one point in a natural river will contain both locally derived and upstream inherited flow structures, according to the range of scales of topography present.