Revision as of 01:47, 27 April 2021

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  <font color="green"! downstream tidal boundary</font>
!!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
End Group
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	
End Group
!_________________________________________________________________
! This is required due to adding deposition and settling.
Material == 0
      Layer == 1
            dry density == 1890.,1890	
      End layer
end material</font>
!Upstream
<tt>seed particles</tt><tt> ==</tt> point,  10796.514,8285.014
      <tt>particle groups</tt><tt> ==</tt> fineSed, Gravel
      <tt>group mass</tt><tt> ==</tt> 100,100
<tt>end seed
! OUTPUT SETTINGS
_________________________________________________________________
<tt>output dir</tt><tt> ==</tt> ..\results\
<tt>output</tt><tt> ==</tt> ptm_netcdf
      <tt>output groups</tt><tt> ==</tt> all
      <tt>output parameters</tt><tt> ==</tt> age, state_age, mass, uvw, uvw_water, depth, water_depth
      <tt>output interval</tt><tt> ==</tt> 300.
<tt>end output