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(c)
often takes place with a celerity that is approximately proportional to the square root of the
bed slope;
(d)
usually has a sufficiently high Reynolds number so that the effect of bed roughness becomes
negligible;
(e)
can be predicted fairly well by solving the continuity equation together with the complete
shallow water momentum equation;
(f)
is usually not greatly affected by the impact of the raindrops on the flowing water in the
river;
(g)
can be described by the kinematic wave approach only when the channel bed is relatively
smooth, so that the GM roughness, n , is small;
(h)
can be described by the kinematic wave approach: the approximation is better for a channel
with a small slope than for one with a larger slope (assume everything else is the same);
(i)
can be described by the shallow water equations even when the river is not very wide.
7.18
Multiple choice. Indicate which of the following statements are correct. The classical, Muskingum
flood routing method:
(a)
is not suitable to describe diffusion (i.e. “broadening” and “flattening”) of a flood wave as
it travels downstream, because it is based on the kinematic wave assumption;
(b)
is not suitable to predict the propagation of bores or moving hydraulic jumps, because
it neglects change-in-momentum effects (in other words, it is based on the assumption
( DV / Dt ) = 0;
(c)
can be used to describe a stationary hydraulic jump by adjusting the velocity of the moving
coordinate system;
(d)
is based on the assumption that the storage of water in the channel is a linear function both
of inflow rate and of outflow rate;
(e)
in its general form requires that the peak of the outflow flood occur at the time when the
inflow flood has the same rate of flow.
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