Hivel2D users manual
b. The model is compiled to solve problems having meshes as large as 2000 nodes and
2000 elements and will run on a IBM-compatible personal computer having at least
8 MB of RAM.
c. A Newton-Raphson iteration is used within each time-step.
d. The mild slope assumption is invoked. This means the slope should be less than
about 0.05. This assumes that the slope is geometrically mild, not hydraulically
mild.
e. Boundary conditions are specified for any combination of supercritical and
subcritical inflow and outflow.
f. Boundary conditions are constant over the simulation period.
g. Boundary roughness (Manning's n) is specified on an element type basis.
h. A user-specified parameter α produces either first-order or second-order backward
temporal differences.
i. A Petrov-Galerkin approach in which the test function is weighted upwind along
characteristics is employed. The degree of upwinding and thus stability is
determined by the parameters β SM and βSH . Defaults are β SM = 0.25 and βSH =
0.5.
j. A shock detection mechanism based upon the energy variation per element is used
to invoke βSH .
k. Turbulent eddy viscosity is calculated based upon simple user-specified parameters
CSM and CSH using velocity, depth, and roughness.
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Chapter 2 HIVEL 2D overview
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