Model:TopoFlow-Channels-Diffusive Wave: Difference between revisions
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*Init. depth: Scalar 0.00000000 [m] | *Init. depth: Scalar 0.00000000 [m] | ||
*Sinuosity: Scalar 1.00000000 [m/m] | *Sinuosity: Scalar 1.00000000 [m/m] | ||
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*ADD ADDITIONAL, OUTPUT OPTIONS HERE. | *ADD ADDITIONAL, OUTPUT OPTIONS HERE. | ||
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|Input format=ASCII, Binary | |Input format=ASCII, Binary | ||
|Describe output parameters=This component computes the following variables, as grids: | |Describe output parameters=This component computes the following variables, as grids: | ||
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*f = friction factor [none] | *f = friction factor [none] | ||
*S_bed = free-surface slope [m/m] | *S_bed = free-surface slope [m/m] | ||
The user can choose which, if any, of these to save. Each may be saved as a grid sequence, indexed by time, in a netCDF file, at a specified sampling rate. Each may also be saved for a set of "monitored" grid cells, each specified as a (row,column) pair in a file with the name | The user can choose which, if any, of these to save. Each may be saved as a grid sequence, indexed by time, in a netCDF file, at a specified sampling rate. Each may also be saved for a set of "monitored" grid cells, each specified as a (row,column) pair in a file with the name: <case_prefix>_outlets.txt. With this option, computed values are saved in a multi-column text file at a specified sampling rate. Each column in this file corresponds to a time series of values for a particular grid cell. For both options the sampling rate must no smaller than the process timestep. | ||
|Output format=ASCII, Binary | |Output format=ASCII, Binary | ||
|Pre-processing software needed?=Yes | |Pre-processing software needed?=Yes | ||
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ΔV(i,t)= Δt * [ R(i,t) Δx Δy - Q(i,t) + Σk Q(k,t) ] = change in water volume [ | ΔV(i,t)= Δt * [ R(i,t) Δx Δy - Q(i,t) + Σk Q(k,t) ] = change in water volume [m^3], mass conservation | ||
d = {[ | d = {[ w^2 + 4 tan(θ) V / L]^1/2 - w } / [2 tan(θ)] = mean water depth in channel segment [m] (if θ > 0) | ||
d = V / [w * L] = mean water depth in channel segment [m] (if θ = 0) | d = V / [w * L] = mean water depth in channel segment [m] (if θ = 0) | ||
Q = v * Aw = discharge of water [ | Q = v * Aw = discharge of water [m^3 / s] | ||
v = n-1 * Rh^2/3 * S^1/2 = section-averaged velocity [m / s], Manning's formula | v = n^(-1) * Rh^(2/3) * S^(1/2) = section-averaged velocity [m / s], Manning's formula | ||
v = ( g * Rh * S)1/2 * LN( a * d / z0) / κ = section-averaged velocity [m / s], Law of the Wall | v = ( g * Rh * S)^(1/2) * LN( a * d / z0) / κ = section-averaged velocity [m / s], Law of the Wall | ||
Rh = Aw / Pw = hydraulic radius [m] | Rh = Aw / Pw = hydraulic radius [m] | ||
Aw = d * [w + (d * tan(θ))] = wetted cross-sectional area of a trapezoid [ | Aw = d * [w + (d * tan(θ))] = wetted cross-sectional area of a trapezoid [m^2] | ||
Pw = w + [2 * d / cos(θ)] = wetted perimeter of a trapezoid [m] | Pw = w + [2 * d / cos(θ)] = wetted perimeter of a trapezoid [m] | ||
Vw = | Vw = d^2 * [ L * tan(θ) ] + d * [L * w] = wetted volume of a trapezoidal channel [m] | ||
|Describe length scale and resolution constraints=Recommended grid cell size is around 100 meters, but can be parameterized to run with a wide range of grid cell sizes. DEM grid dimensions are typically less than 1000 columns by 1000 rows. | |Describe length scale and resolution constraints=Recommended grid cell size is around 100 meters, but can be parameterized to run with a wide range of grid cell sizes. DEM grid dimensions are typically less than 1000 columns by 1000 rows. | ||
|Describe time scale and resolution constraints=The basic stability condition is: dt < (dx / u_min), where dt is the timestp, dx is the grid cell size and u_min is the smallest velocity in the grid. This ensures that flow cannot cross a grid cell in less than one time step. Typical timesteps are on the order of seconds to minutes. Model can be run for a full year or longer, if necessary. | |Describe time scale and resolution constraints=The basic stability condition is: dt < (dx / u_min), where dt is the timestp, dx is the grid cell size and u_min is the smallest velocity in the grid. This ensures that flow cannot cross a grid cell in less than one time step. Typical timesteps are on the order of seconds to minutes. Model can be run for a full year or longer, if necessary. |
Revision as of 00:45, 16 February 2010
Contact
Name | Scott Peckham |
Type of contact | Model developer |
Institute / Organization | CSDMS, INSTAAR, University of Colorado |
Postal address 1 | 1560 30th street |
Postal address 2 | |
Town / City | Boulder |
Postal code | 80305 |
State | Colorado |
Country | USA"USA" is not in the list (Afghanistan, Albania, Algeria, Andorra, Angola, Antigua and Barbuda, Argentina, Armenia, Australia, Austria, ...) of allowed values for the "Country" property. |
Email address | Scott.Peckham@colorado.edu |
Phone | 303-492-6752 |
Fax |
TopoFlow-Channels-Diffusive Wave
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