Insteady Flow Accumulating Discharge

[philemon]

Hello.
My model is running perfectly for steady and unsteady flows (no errors). However, the results from the unsteady flow simulation are quite strange. When running an artificial wave (0h: 0 m3/s, 12 h: 2 m3/s, 24 h: 0 m3/s) at the upstream boundary, the maximum discharge at the downstream end reaches values higher then 6 m3/s.

There seem to be some routing effects within the model. How can I eliminate such effects?

Many thanks for an immediate answer.

[cameron]

What is your timestep for the unsteady model and what is the spacing of your cross-sections. I would suggest lowering the timestep or interpolating cross-sections to see if either one changes the results.

[Anonymous]

Two things might have happened here. (1) The peak discharge can increase in the downstream direction (absent intervening flows) in steep reaches. (2) The sampling of the output might be on a frequency that captures the peak outflow, but not the peak inflow. Suggest comparing the complete inflow and outflow hydrographs rather than the summary.

[Author]

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