Breach growth formula (Water Overlay): Difference between revisions

From Tygron Support wiki
Jump to navigation Jump to search
No edit summary
No edit summary
Line 22: Line 22:
* MF = Material factor, set to 1.3 (average for sand and clay levees)
* MF = Material factor, set to 1.3 (average for sand and clay levees)
* G = Acceleration factor of gravity
* G = Acceleration factor of gravity
* BH = The {{inlink|BREACH_HEIGHT}} attribute of the breach.
* BH = The [[Breach height (Water Overlay)|BREACH_HEIGHT]] attribute of the breach.
* BW = The {{inlink|BREACH_WIDTH}} attribute of the breach.
* BW = The [[Breach width(Water Overlay)|BREACH_WIDTH]] attribute of the breach.
* BS = The {{inlink|BREACH_SPEED}} attribute of the breach.
* BS = The [[Breach speed(Water Overlay)|BREACH_SPEED]] attribute of the breach.
* EL = Current external water level.
* EL = Current external water level.



Revision as of 13:22, 4 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) / Uc) * log10 (1 + (0.04 * G / Uc) * 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.

References

  1. 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)

Template:WaterOverlay nav