Opened 16 years ago
Closed 12 years ago
#278 closed enhancement (fixed)
Implement Inflow Boundary Condition
Reported by: | ole | Owned by: | ole |
---|---|---|---|
Priority: | normal | Milestone: | |
Component: | Functionality and features | Version: | |
Severity: | normal | Keywords: | |
Cc: |
Description (last modified by ole)
Create boundary object that can apply a hydrograph to a boundary segment. The units are cubic meters per second and it should be time varying.
The challenge is to estimate the depth along the boundary segment based on Manning's formula and the slope into the domain.
Q = V*A V = R^{2/3} * S^{1/2}/n Where Q is the inflow [m^3/s] A is the area of the boundary cross section V is the estimated velocity R is the perimeter width ~ estimated depth S is the slope of the energy line ~ inward bedslope
the estimated quantities may be the result of an iterative process. Please comment on this everyone.
Change History (3)
comment:1 Changed 16 years ago by ole
- Description modified (diff)
comment:2 Changed 15 years ago by ole
comment:3 Changed 12 years ago by habili
- Resolution set to fixed
- Status changed from new to closed
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Ted Rigby sent the following description through on 15th April 2009:
Along an inflow boundary depth and velocity will vary (faster where deeper). Averaging momentum would not be realistic. I attach a rather quick python like (I hope) outline of how the inflow boundary elevation is traditionally estimated in fortran. assume boundary flow is normal - imposes need on user to make boundary reasonably sensible for each triangle on bdry ! (w is triangle base width along bdry -- as in Q= r^{5/3 *(w/n*sqrt(S)) }
for elevation of water surface in range (lowest plus a bit to heaps, inc by reasonable small amount)
some cleverer code uses a crude estimate of elev made along the lines you suggested and the algorithm coded to converge on the correct elev within a tolerance All use iteration though -- I know of no direct solution for computing the elevation for a Q Some funnies to watch