Timestep formula (Water Overlay): Difference between revisions
Jump to navigation
Jump to search
No edit summary |
No edit summary |
||
| (2 intermediate revisions by 2 users not shown) | |||
| Line 1: | Line 1: | ||
An adaptive timestep is implemented according to Kurganov and Petrova (2007) | An adaptive timestep is implemented according to Kurganov and Petrova (2007){{ref|Kurganov1}}. At every timestep, the courant-number is kept smaller than 0.25 for every active computation cell. | ||
[[File:Inundation_overlay_03.PNG|400px]] | [[File:Inundation_overlay_03.PNG|400px]] | ||
| Line 9: | Line 9: | ||
* if the waterdepth increases, the timestep is assumed to be not larger than the formula above. | * if the waterdepth increases, the timestep is assumed to be not larger than the formula above. | ||
If the numerical flux decreases, larger timesteps are allowed than set by Kurganov and Petrova | If the numerical flux decreases, larger timesteps are allowed than set by Kurganov and Petrova{{ref|Kurganov1}}, depending on the [[Calculation preference formula (Water Overlay)|configured calculation]]. | ||
{{article end | |||
|references= | |||
<references> | <references> | ||
{{ref|Kurganov1 | |||
|name=A Second-Order Well-Balanced Positivity Preserving Central-Upwind Scheme for the Saint-Venant System | |||
|author=Kurganov A, Petrova G (2007) | |||
|page=15 | |||
|source= | |||
|link=http://www.math.tamu.edu/~gpetrova/KPSV.pdf | |||
|lastvisit=2018-06-29 | |||
}} | |||
</references> | </references> | ||
}} | |||
{{ | {{WaterOverlay formula nav}} | ||
Latest revision as of 11:48, 17 October 2025
An adaptive timestep is implemented according to Kurganov and Petrova (2007)[1]. At every timestep, the courant-number is kept smaller than 0.25 for every active computation cell.
Especially at low depths, choosing the appropriate timestep is critical to avoid numerical instability. Therefore the following principles are used to determine the right time step:
- the timestep is choosen so that all computation cells follow one of the following criteria.
- if a cells waterdepth is below the flooding threshold, 5 * 10-3 (m) there is no flow assumed between that cell and it neigboring cell.
- if the cells waterdepth is above above the flooding threshold, the maximum timestep is assumed to be 100 * the waterdepth at the cell.
- if the waterdepth increases, the timestep is assumed to be not larger than the formula above.
If the numerical flux decreases, larger timesteps are allowed than set by Kurganov and Petrova[1], depending on the configured calculation.
References
- ↑ 1.0 1.1 A Second-Order Well-Balanced Positivity Preserving Central-Upwind Scheme for the Saint-Venant System ∙ Kurganov A, Petrova G (2007) ∙ Page(s): 15 ∙ Found at: http://www.math.tamu.edu/~gpetrova/KPSV.pdf ∙ (last visited: 2018-06-29)
- Models
- Surface • Ground • Rain • Evapotranspiration • Infiltration • Elevation • Breach • Sewer • Storage • Tracer flow • Border • Order
- Model formulas
- Timestep • Season • Surface water level • Groundwater level
- Flow formulas
- Surface flow • Surface infiltration • Ground flow • Ground infiltration • Surface evaporation • Ground evaporation • Ground bottom flow
- Hydraulic structure formulas
- Culvert • Weir • Breach growth • Breach flow • Pump • Sewer Overflow • Inlet • Drainage
- Related