Armfield S12-MKII, Инструкция по эксплуатации

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Armfield Instruction Manual
30
Constants
Specific weight of sand = 2650 M/m³
Specific weight of water = 9810 N/m³, but alters with water temperature
g (gravitational acceleration) = 9.81 m/s²
Kinematic Viscosity (m²/s) = 0.00000114, but varies with temperature
Median Grain Diameter of Sediment Bed = Determine from sand used
Other Equations
Channel cross-sectional area (m²) = Average channel width (m) x Average channel
depth (m)
Wetted perimeter (m) = bed width (m) + 2 x bank height (m)
Hydraulic radius (m) = Channel cross-sectional area (m
2
) ÷ Wetted perimeter (m)
Velocity (m/s) = Discharge (m³/s) Channel cross-sectional area (m²)
Reynolds Number = (Velocity (m/s) x Hydraulic radius (m)) Kinematic viscosity
(m²/s)
Froude Number = Velocity (m/s) ( (g x Average depth (m)))
Boundary Shear Stress (N/m²) = Specific weight of water (N/m³) x Hydraulic radius
(m) x Slope (m per m)
Shear Velocity = (g x Hydraulic radius (m) x Slope (m per m)
Boundary Reynolds Number = (Shear velocity (m/s) x Grain diameter (m)) +
Kinematic viscosity (m²/s)
Shields Parameter = Boundary shear stress (N/m²) (Specific weight of water
(N/m³) x 1.65 x Grain diameter (m))
Total Stream Power (J/s) = Specific weight of water (N/m 3 ) x Discharge (m 3 /s) x Slope
(m/m)
Specific Stream Power (watts/m) = Total Stream Power ÷ width (m) = Velocity (m/s) x
Specific weight of water (N/m³) x Depth (m) x Slope (m per m)
Critical Stream Power (Watts/m) = 290 x Grain diameter (m) 1.5 x g x Log ((12 x Depth
(m)) Grain diameter (m))
Net Stream Power (J/s) = Total stream power (J/s) – Critical stream power (J/s)
Bagnold’s Bedload Equation (kg/ms) = (Net stream power (J/s) ½ g) 1.5 x (Depth
(m) 0.1) -2/3 x 0.1 x Grain diameter (m) 0.0011) –1/2
Channel Sinuosity = Channel length (m) Valley length (m)
Total thalweg length (m) = Sum of all channel thread lengths (m)
Braiding Intensity = Number of sub-channels per unit channel length