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Test Case34

Lake Signell

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This case provides a fundamental check of the ability of a model to represent 1) wind driven transport in a closed basin, 2) wave-current influences on bottom friction and sediment resuspension, 3) flux of two grain sizes from the bed, and 4) resuspension, transport, and deposition of suspended-sediment. Lake Signell derives its name from the paper by Signell et al. (1990) Journal of Geophysical Research 95(C6): 9671-9673.

Figure showing the layout of test case 3, the hypothetical Lake Signell

Domain

The domain is an enclosed basin, rectangular in plan view, with a sloping bottom.
Length (east-west) l = 50,000 m
Width (north-south) w =10,000 m
Depth h = 18 m at the northern end, decreasing linearly to 2 m at the southern end

Bottom Sediment

Grain size:
Sand  
Size (D50) = 0.1 mm (fine sand)  
Density ρs = 2650 kg/m³  
Settling velocity = 0.1 mm/s  
Critical shear stress τc = 0.05 N/m²  
Thickness = 0.005 m  
Erosion rate = 5 e-5 kg/m² /s  


Forcing

No Coriolis
No heating/cooling

Wind:
Wind speed = 13 m/s (tau = 0.25 Pa), blowing along the lake to the east
Waves:
RMS wave height = 0.5 m
Period = 5 seconds
Direction: propagating in wind direction

Initial Conditions

u = 0 m³ /s
Salinity = 0
T = 20° C

Boundary Conditions

North, south, east, and west sides = walls with no fluxes, no friction
Bottom roughness zo = 0.015 m in absence of waves
Surface roughness zos = 0.02 m
Sediment flux calculated by model
Surface = free surface, no fluxes of heat or salt (momentum fluxes associated with wind)

Output at Steady State (ASCII files suitable for plotting)

Velocity field at profile at x = 40,000 m
Bed thickness

Physical Constants

Gravitational acceleration g = 9.81 m/s²
Von Karman's constant κ = 0.41
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 3: Lake Signell

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