7387

• UCREFRP Catalog Number: 7387
• Author: U.S. Bureau of Reclamation.
• Title: Glen Canyon Environmental Studies Executive Summaries of Technical Reports.
• USFW Year: 1988.
• USFW - Doc Type: \
• Copyright Material: NO

Figure 3 (below) illustrates cross sections through
five parts of House Rock Rapid. Note the dramatic
change in cross-sectional area of the flow in the
different parts of the rapid, reflecting differences of
more than one order of magnitude in average flow
velocity, u (shown on each cross section) within the
rapid. The Froude number (Fr, also shown on each cross
section) is a characteristic dimensionless number that
indicates the relative importance of kinetic and
potential energy. The Froude number is very small
(approximately 0.05) in the backwater, indicating that
nearly all of the energy of the water is stored in
potential energy (i. e., depth). The Froude Number
increases to unity in the convergent reach and reaches
a value of nearly 2 in the most tightly constricted
part of the rapid where the flow is shallowest. In
this section, the flow is supercritical, and the
kinetic energy of the water is more important in
determining the flow dynamics than is the potential
energy. Standing waves are stable in supercri tical
flow, and these waves are the major hydraulic features
of the rapids. The flow decelerates to Froude Number
unity in the diverging section of the rapid near the
downstream eddy.

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