3D numerical morphodynamic models

3D numerical morphodynamic models

Type

Hydromorphological models

Basic principles

Fundamental equations for conservation of water mass and water flow momentum, time-averaged over all turbulent fluctuations (RANS = Reynolds Averaged Navier-Stokes equation) or time-averaged over only the smaller turbulent fluctuations (LES = Large Eddy Simulation). Lagrangian equations for pickup, transport and deposition of sediment particles. Exner equation for conservation of sediment mass.

Outputs

Flow velocities, water depths, water levels, flow shear stresses. Sediment transport, bed level, erosion, sedimentation.

Rivertypes

• Reach
•    Reach

Related Pressures

• Alteration of instream habitat
• Sand and gravel extraction
• Sedimentation and sediment input
• Embankments, levees or dikes
• Loss of vertical connectivity
• Impoundment
• Alteration of riparian vegetation
• Channelisation / cross section alteration

Related Measures

• Reduce anthropogenic flow peaks
• Modify hydropeaking
• Shorten the length of impounded reaches
• Increase flood frequency and duration in riparian zones or floodplains
• Favour morphogenic flows
• Link flood reduction with ecological restoration
• Ensure minimum flows
• Manage aquatic vegetation
• Establish environmental flows / naturalise flow regimes
• Create low flow channels in over-sized channels
• Narrow water courses
• Widen water courses
• Allow/increase lateral channel migration or river mobility
• Remeander water courses
• Shallow water courses
• Add sediments
• Modify aquatic vegetation maintenance
• Initiate natural channel dynamics to promote natural regeneration
• Introduce large wood
• Remove sediments
• Remove bank fixation
• Remove or modify in-channel hydraulic structures
• Reduce impact of dredging
• Recreate gravel bar and riffles

Useful references

Selected software systems

Delft3D: http://www.deltaressystems.com/hydro/product/621497/delft3d-suite

FLOW-3D: http://www.flow3d.com/

iSed

SSIIM: http://folk.ntnu.no/nilsol/ssiim/

TELEMAC-3D

Theoretical background

Hervouet J.M., Hubert J.-L., Janin J.-M., Lepeintre F., Peltier E. (1994): The computation of free surface flows with TELEMAC: an example of evolution towards hydroinformatics. Journal of Hydraulic Research, Vol. 32, extra issue, pp. 45-64.

Olsen N.R.B (1999): Computational Fluid Dynamics in Hydraulic and Sedimentation Engineering. Class Notes, Norewgian University of Technology, Trondheim.

Tritthart M. (2005): Three-Dimensional Numerical Modelling of Turbulent River Flow using Polyhedral Finite Volumes. Wiener Mitteilungen Wasser-Abwasser-Gewässer, Band 193, Institut für Wasserbau und Ingenieurhydrologie, TU Wien.

Tritthart M., Gutknecht D. (2007): Three-Dimensional Simulation of Free-Surface Flows using Polyhedral Finite Volumes. Engineering Applications of Computational Fluid Mechanics, 1, pp. 1-14.

Sample applications

Olsen N.R.B (2000): A three-dimensional numerical model for simulation of sediment movements in water intakes with multiblock option. User´s Manual, Norwegian University of Science and Technology, Trondheim.

Olsen N.R.B. (2000): CFD modeling of bed changes during flushing of a reservoir. Proc., Hydroinformatics 2000, Iowa, USA.

Olsen N.R.B. (2002): Estimating meandering channel evolution using a 3D CFD model. Proc., Hydroinformatics 2002, Cardiff, pp.52-57.

Tritthart M., Schober B., Liedermann M., Habersack H. (2009): Development of an Integrated Sediment Transport Model for a Large Gravel Bed River. Proceedings, 33rd IAHR Congress, Vancouver, Canada.