Sediment Transport with Particle Tracking
The TUFLOW Particle Tracking Module (PTM) allows the 2D or 3D simulation of discrete Lagrangian particles as they are transported by the flow field (or other drivers such as wind or waves). Particle behavior such as settling, buoyancy, decay, sedimentation and re-suspension can all be simulated. It can be run in conjunction with the sediment transport module to simulated the fate and age of sediment particles within the hydraulic model.
In this optional exercise we will take the existing FMA2_SED_003 model and add some particle tracking to track the input of particles.
Copy and paste the existing FMA2_SED_003.fvsed file and rename as FMA2_SED_003a.fvsed.
Under the Boundary Conditions Block add the following particle tracking block to reference a particle tracking file that we will generate.
!PARTICLE TRACKING INPUT Particle Tracking Control File == FMA2_SED_003a.fvptm
In the output commands block, under the current specification for the XMDF file add the following block to output results to a netcdf file. This will output hydraulic parameters, sediment transport parameters as well as results from the particle tracking module.
output == netcdf output parameters == h,v,d, Rhow, Taub, TauC, PTM_1, PTM_2, PTM_BED_2 output interval == 900. end output
Save and close the file.
Generate a new file called FMA2_SED_003a.fvptm. This is where we will generate the characteristics of our particle tracking module. We will use the same sediment characteristics that we have already applied to the sediment transport model. Add the following commands
! PTM to assess fate of STP plume - TEST POLYGON SEEDING ! use nodestring definition from HD model to allow particles to leave model domain. Open boundary nodestring == 2 ! downstream tidal boundary
!TIME COMMANDS !_________________________________________________________________ lagrangian timestep == 120. ! seconds eulerian timestep == 120. ! seconds
! Sediment Transport COMMANDS (required if a particle group interacts with bed) bed roughness model == ks bed roughness parameters == 0.01,0.01 ! ksc, ksw
!Global COMMANDS Nscalar == 1
!PARTICLE GROUP COMMANDS !_________________________________________________________________
Group == fineSed
d50 == 0.000002 particle density == 2650 Settling model == constant settling parameters == 0.0002 !(m/s) deposition model == ws0 Erosion Model == Mehta Erosion parameters == 0.1, 0.5, 0.5 !Er, taucr, alpha
Group == Gravel
d50 == 0.032 particle density == 2650 Settling model == constant settling parameters == 0.6 !(m/s) Critical stress model == Soulsby Bed load model == MPM_Shimizu Bed load parameters == 8.0, -1 ,1.5
! This is required due to adding deposition and settling. Material == 0 Layer == 1 dry density == 1890.,1890 End layer
!Upstream seed particles == point, 10796.514,8285.014 particle groups == fineSed, Gravel group mass == 100,100 end seed
! OUTPUT SETTINGS !_________________________________________________________________
output dir == ..\results\
output == ptm_netcdf
output groups == all output parameters == age, state_age, mass, uvw, uvw_water, depth, water_depth output interval == 300.