Flooding Overlay

What is the Inundation overlay

The inundation is developed for the computation of surface (water) flow in a wide range of applications. These applications include large scale inundations due to dike breaches and inundations at the bottom of hill-slopes. Therefore the commonly applied 2D Saint Venant Equations are implemented on an explicit highly parallel applicable numeric scheme suitable for Tygron GPU clusters.

2D Saint Venant equations

The 2D Saint Venant equations describe the conservation of mass in a gridcell and the conservation of momentum in both x and y, direction:

The Saint Venant equations describe the following processes:

• friction
• bed slope
• water pressure
• convection (changes in bathemetry over space)
• inertia (increase or decrease of velocity over time)

Numerical scheme

The Tygron Engine Inundation module relies on an explicit finit volume method, taken from Kurganov and Petrova (2007). This scheme relies on a reconstruction of cell bottom, water level and velocity at the interfaces between computational cells as proposed by Lax and Wendroff (see Rezzolla, 2011). The reconstruction method, taken from Bolderman et all (2014) ensures numerical stability, especially at the wetting and drying front of a flood wave.

References

• Rezzolla L (2011) ∙ Numerical Methods for the Solution of Partial Differential Equations
• Bollermann A, Chen G, Kurganov A and Noelle S (2014) ∙ A Well-Balanced Reconstruction For Wetting/Drying Fronts https://www.researchgate.net/publication/269417532_A_Well-balanced_Reconstruction_for_Wetting_Drying_Fronts
• Kurganov A, Petrova G (2007) ∙ A Second-Order Well-Balanced Positivy Preserving Central-Upwind Scheme for the Saint-Venant System ∙ http://www.math.tamu.edu/~gpetrova/KPSV.pdf