Breach growth formula (Water Overlay): Difference between revisions
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Using the height difference, the breach width increase is calculated. | Using the height difference, the breach width increase is calculated. | ||
: ''ΔB = 1.3 * ((G^0.5 * H^1.5) / | : ''ΔB = 1.3 * ((G^0.5 * H^1.5) / BS) * log10 (1 + (0.04 * G / BS) * Δt / 3600)'' | ||
The current breach width is then equal to the last calculated breach width, plus the calculated additional breach width. | The current breach width is then equal to the last calculated breach width, plus the calculated additional breach width. | ||
Revision as of 07:33, 8 April 2019
Breaches can grow when water flows from the virtual external water source into the hydrological model[1].
First, the difference in height of the water on either side of the breach is calculated.
- H = abs( max(0, EL - BH) - max(0, WL - BH) )
Using the height difference, the breach width increase is calculated.
- ΔB = 1.3 * ((G^0.5 * H^1.5) / BS) * log10 (1 + (0.04 * G / BS) * Δt / 3600)
The current breach width is then equal to the last calculated breach width, plus the calculated additional breach width.
- Bnew = Bold + ΔB
Where:
- B = The total calculated breach width, initially equal to BW.
- Δt = Computational timestep.
- ΔB = The calculated width increase of the breach.
- H = The difference between the height of the water columns on either side of the breach.
- MF = Material factor, set to 1.3 (average for sand and clay levees)
- G = Acceleration factor of gravity
- BH = The BREACH_HEIGHT attribute of the breach.
- BW = The BREACH_WIDTH attribute of the breach.
- BS = The BREACH_SPEED attribute of the breach.
- EL = Current external water level.
See also
References
- ↑ Verheij, H.J. ∙ Aanpassen van het bresgroeimodel in HIS-OM: Bureaustudie ∙ found at: http://resolver.tudelft.nl/uuid:aedc8109-da43-4a03-90c3-44f706037774 ∙ (last visited 2019-03-08)