Session B.pdf - Clarkson University

17th International Symposium on Ice
Saint Petersburg, Russia, 21 - 25 June 2004
International Association of Hydraulic Engineering and Research
TWO-DIMENSIONAL MODEL OF RIVER-ICE PROCESSES
USING BOUNDARY-FITTED COORDINATE
Mao Zeyu 1 , Zhang Lei 1 , Yue Guangxi 2
ABSTRACT
River ice is natural phenomena in the northern of China under specific conditions of
meteorology, geomorphology and hydraulics. The ice-related problems often makes the
function and management of structures or channels very difficult. In this paper a twodimensional
river-ice numerical model under boundary-fitted coordinate is developed to
accurately simulate complicated boundary condition. The numerical model consists of
hydraulics model, flow temperature model, frazil-ice distribution model, and ice
transportation under ice cover. MacCormack scheme is used to solve the equations. The
model is validated with field data on the Hequ Section of Yellow River.
INTRODUCTION
The river-ice evolution is influenced by river hydraulics, thermodynamics,
geomorphology and freezing, etc (Mao and Wu etal., 2002). Characteristic of flow in
natural rivers are more complicated compared to that in straight channel, especially in
meandering river. The one-dimensional model is only applicable for straight channel. It
is well known that hydraulic conditions affect significantly ice condition, and the
meander of river makes it impossible to use rectangular Cartesian coordinates to deal
with complex geometric boundaries accurately. Boundary-fitted-coordinate (BFC in
shortened form) is a kind of curvilinear coordinate, and can represent accurately the
actual boundary. By means of BFC, the solution can be conducted on the fixed
rectangular perpendicular grids, Fig.1. In this paper, two-dimensional numerical model
of river-ice using BFC is developed, including models of river hydraulics, ice transport,
thermal and freezing. The basic procedure is illustrated in Fig.2.
1 Supported by Tsinghua University Research Foundation (No. JC2002006). Department of Hydraulic Engineering,
Tsinghua University, Beijing 100084, China; E-mail address:maozeyu@tsinghua.edu.cn
2 Department of Thermal Engineering, Tsinghua University, Beijing 100084, China
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