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Test Case 1

Channel Flow

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This case provides a fundamental check of the ability of a model to 1) represent a simple flow, 2) flux material from the bed, and 3) develop a suspended-sediment profile.

Figure showing the layout of test case 1, a straight flume.

Domain

The model domain is a long, narrow rectangular box.
Length l = 10,000 m
Width w = 1000 m
Depth h = 10 m
Flat bottom
Fresh water, T = 20° C
Salinity = ‰

Bottom Sediment

Single grain size on bottom
Size (D50) = 0.15 mm (fine sand)
Density ρs = 2650 kg/m³
Settling velocity = 0.001 m/s
Critical shear stress τc= 0.05 N/m²(0.5 dynes/cm²)
Fractional bed concentration (1-porosity) = 0.90
Infinite supply of sediment (no erosion, no armoring)

Forcing

Inflow boundary condition only
No Rotation (f z0)
No wind
No heating/cooling

Boundary Conditions

Inflow maintained as steady flow, depth-mean flow <u> = 1 m/s
Outflow = open
Sides = walls with no fluxes, no friction
Bottom roughness z0 = 0.005
Sediment flux calculated by model
Surface = free surface, no fluxes

Output (ASCII files suitable for plotting)

Velocity profile at x = 8000 m
Suspended sediment profile at x = 8000 m
Time series of net rate of sediment flux from bed and/or concentration at specified levels

Physical Constants

Gravitational acceleration g = 9.81 m/s²
Von Karman's constant κ = 0.41
Water density ρw = 998 kg/m³
Dynamic viscosity (and minimum diffusivity) ν = 1e-6 m²/s

Note

If a model incorporates physical constants that differ from these, and/or automatically calculates some values specified here, please specify the values used.

Results

Solution to Test Case 1: Straight Flume

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