Processes in sediment module MUSTANG

There are 2 options (2 versions) :

• version 1 :

  used by default with key_sedim_MUSTANG, based on the model “mixsed”

  developped by Le Hir et al (2011)

• version 2 :

  used with key_sedim_MUSTANG && key_MUSTANG_V2,

  recently developped by B. Mengual and P. Le Hir

  to improve layer and porosity management,

  as well as erosion and deposition processes with mixing sediment (at cohesif and non cohesif regime).

  The bedload processes have taken into account in this new version (based on the developments of A. Rivier (2017))

  (see Mengual, 2018 - Seine Aval report - Morphoseine Project)

• The different computation steps for sediment module are :

  • 1. actualization of bathymetrie if morphodynamical coupling
  • 2. computing bottom shear stress \(=\tau_s\) f(U,waves, roughness)(Shear stress Process)
  • 3. computing settling rate in water column (Setlling Process)
  • 4. computing aggregation /fragmentation processes (Flocculation Process)
  • 5. computing settling trends (Setlling Process)
  • 6. extrapolation of sand concentration near bottom
  • 7. sediment consolidation and diffusion/bioturbation into sediment layers (Consolidation Process , Diffusion within sediment and at interface and Bioturbation within sediment)
  • 8. computing total mass eroded transported by suspending or by bedload (Erosion Processes)
  • 9. after particules transport in water column, computing of effective deposit, updating sediment layers (Deposit Processes)
  • 10. throughout the process, calculate the porosity of the sand / mud mixture (Porosity of a multiclass mixture sand/mud)

• Shear stress Process
• Setlling Process
  • Settling fluxes from water to sediment
  • Settling velocities : Modelling strategy
  • Definition of parameters for particulate-sediment substances in variable.dat
  • Free settling velocity
  • Hindered settling velocity
  • Exemples of evolution of settling velocity according to different options
• Flocculation Process
• Deposit Processes
  • Deposit Processes : Version 1
  • Deposit Processes : Version 2
  • Sliding Processes
• Erosion Processes
  • Erosion Processes : Version 1
  • Erosion and Bedload Processes : Version 2
  • Lateral erosion
  • erosion routine diagram - Version V2
• Consolidation Process
• Diffusion within sediment and at interface
• Bioturbation within sediment
• Morphodynamic coupling
• Porosity of a multiclass mixture sand/mud
• Management of sediment layers