| Summary: | Flood routing numerical model aims to predict the flood wave propagation behavior in
unsteady flow field. Understanding of numerical techniques applied to the hydraulic
computation is very supportive to advance flood warning systems and flood control in
Indonesia. This study attempted to model the unsteady flow with one of the 1D numerical
method, the method of characteristics. The simulation model will be applied in case of a
flood wave propagation in the flume.
1 D flow modeling to simulate flood wave propagation in the flume, the flume length
9.0m, manning coefficient = 0:01 m1/3.s, flume width of 40 cm, So = 0.0001 and the upper
boundary condition is a flood that has be set as well as the author of the downstream
boundary condition is critical flow (waterfall).
The results of this study indicate that for stage time (�t = 0:25 s) flood routing results of
a calculation condition is unstable, with the Courant number (Cr) ranging from 0.9902 s
/ d 1.6865. While the routing results in �t= 0:22 s, �t= 0.20 s, �t = 0:18s also showed
numerical instability. In general, discharge oscillation occurs routing routing and water
depth, especially on cross section 10, 15, 20 and 30. The result running model hydraulic
with �t = 0:14 s shows that all of cross section is stable (cross section 1 s/d 46)..The
difference between the flood peak with computer program running �t = 0.16s to 0.14s �t
largest of 1,30% (on cross section 5) and the smallest on the cross section 10 of -0.10% .
Keywords: method of characteristics, flood routing, numerical stability
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