Stefan Wirtz Vom Fachbereich VI (Geographie/Geowissenschaften ...

Experimentelle Rinnenerosionsforschung vs. Modellkonzepte – Quantifizierung der hydraulischen und erosiven Wirksamkeit von Rinnen
The used parameters show a wide range of data. In most cases (12 of 19), the standard
deviation is higher than the mean values, the highest standard deviation – mean - percentage
reaches the transport capacity (224 %), the effective stream power (188.9 %), the sediment
concentration (168.3 %) and detachment and transport rate (both 150 %). The lowest
percentage is calculated for sample density (0.5 %). All initial data are presented in
supporting information tables S1-S18 and the statistical values of the data in table 3.
Table 3 Statistical values of the initial data.
Maximum Minimum Mean Standard Deviation Percentage from Mean
SSC [g L -1 ] 422.30 0.001 52.15 87.78 168.3
D R [kg s -1 m -2 ] 0.96 0.001 0.10 0.15 150.0
T R [lg s -1 ] 2.06 0.001 0.16 0.24 150.0
р [g cm -3 ] 1.26 1.00 1.03 0.005 0.5
Slope [°] 24.50 1.70 9.73 6.90 70.9
T C [kg s -1 ] 3.38 0.001 0.25 0.56 224.0
v [m s -1 ] 2.94 0.04 0.79 0.49 62.0
η [kg s -1 m -1 ] 0.00311 0.00100 0.00126 0.00044 34.9
Water depth [cm] 21.00 0.20 3.99 4.23 106.0
A [cm²] 877.69 0.80 149.21 195.84 131.3
W P [cm] 107.58 4.85 38.21 24.16 63.2
R [cm] 9.65 0.10 2.92 2.12 72.6
τ [Pa] 246.70 0.96 52.38 55.18 105.3
Г [N m -1 ] 172.58 0.10 23.99 35.10 146.3
ω [W m -2 ] 365.28 0.31 41.54 55.91 134.6
ω U [m s -1 ] 0.88 0.001 0.14 0.17 121.4
ω eff [W m -1 ] 37864.55 5.81 3807.14 7192.32 188.9
Re [ ] 86918.88 237.00 19053.94 16226.56 85.2
τ - τ cr [Pa] 244.73 -1.46 49.89 55.11 110.5
3.2 Dynamic viscosity
The measured liquid's dynamic viscosities show a clear correlation to sediment concentration
(see figure 2), and increases with sediment concentration. Visible deviations from the trend
line were noted in samples with low sediment concentrations, which were often rich on
transported organic material. The small branchlets with low weight implicate a low sediment
concentration, but in rheometer measurements, they tilt and a high shear stress is erroneously
measured. The trend line equation has been calculated for samples from different test sites,
the R²-value of 0.92 indicates that this equation can be used for further experiments.
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