Particle Filter is a section in the PTM input where you set up particle-filters. Particle Filter is designed to modify the particle flux at node, without changing hydrodynamic condition, by keeping particles from entering the specified waterbody.



This is for a normal filter, which locates at a node connecting to any waterbody. The PARTICLE_FILTER table defines particle filters by giving them names, associating them to a node and a waterbody, and setting up the passing efficiency (which could be constant value, or time-varying data in DSS).

Filed Descriptions

Name assigned to the particle filter. This is the identifier of the filter used elsewhere to refer to the filter.
The ID of the node to which the filter is attached.
The type and ID of the waterbody to which the filter is attached.
Method for filling in data if the time step of the assigned series is coarser than the time step of the model. See fillin types
DSS or text file in which data are stored. Use consistent case when referring to the same file. You may also enter the word constant if you would like to assign a constant value to the input (the value will be entered in the next column).
The path within the text or DSS file of the time series data. If you used the constant keyword in the Input File column, enter the value here. The stored variable is particle passing efficiency, a float value between 0 ~ 1: 0-block; 1-totally pass.


filter_hor 8    chan:54   last   constant             0
filter_nf  280  chan:357  last   ./Filter_OP_NF.dss   

Usage Notes:

  • Filter locates on 1 node, at the side of 1 waterbody (channel, reservoir, source flow). Every filter is unique with 1 node & 1 waterbody.
  • Filter is 2-directional, and is designed to function differently for each direction <1> waterbody->node: filter serves as a totally block with passing efficiency 0; <2> node->waterbody: filter is designed for changing particle decision-making, with passing efficiency as a re-adjusting factor; thus it only functions when node is connected with multiple waterbodies; i.e. it will not have any effect for a single chain of channel
  • Currently there's no delay concept for filter, because the filter delay rule is unknown, and our major concern is particles' fate (particle's movement only depends on hydro conditions, not interacted with each other)