Session 3A

Session 3A - Furrow irrigation with solute pulse

Project Manager

  Button ”New”
  Name: Furrow
  Description: Furrow irrigation with solute pulse
  Button ”OK”

Main Processes

  Heading: Furrow irrigation with solute pulse
  Check ”Water Flow” and ”Solute Transport”
  Button ”Next”

Geometry Information

  Type of Flow: Vertical Plane
  Geometry Type: General
  Number of materials: 1
  Length Units: cm
  Button ”Next”

Time Information

  Time Units: Days
  Final time: 100
  Initial Time Step: 0.1
  Minimum Time Step: 0.001
  Maximum Time Step: 5
  Button ”Next”

Print Information

  Check All
  Number of Print Times: 18
  Button ”Select Print Times”: 0.5, 1, 2.5, 5 10, 20, 30, 40, 50, 50.5, 51, 52.5, 55, 60, 70, 80, 90, 100
  Button ”Next”

Water Flow - Iteration Criteria

  Water content tolerance: 0.0005
  Pressure head tolerance: 0.1
  Lower Limit of the Tension Interval: 0.001
  Upper Limit of the Tension Interval: 200
  Button ”Next”

Water Flow - Soil Hydraulic Model

  Button ”Next”

Water Flow - Water Flow Parameters

  Catalog of Soil Hydraulic Properties: Silt
  Button ”Next”

Solute Transport - General Information

  Select GFE with artificial dispersion
  Pulse Duration = 50 d
  Button ”Next”

Solute Transport - Solute Transport Parameters

  Diffusion Coefficient = 10
  Disp.L = 1
  Disp.T = 0.1
  Button ”Next”

Solute Transport - Transport Parameters

  CBound1=1
  Button ”Next”

Meshgen-2D: Geometry
Window Coordinates: X=150, Y=50, Width= 400, Hight=150
Set view Stretching factors according to given extents
Menu: Insert->Line->Graphically
Menu: Tools->Circle Input Mode->Center and Radius
Menu: Insert->Circle->Numerically: x=150, y=25, r=5
Save

Meshgen-2D: Boundary Points
Toolbar Button: ”Edit Boundary Points”
Button ”Number of Boundary Points”:
  Outside boundary: 80
  Drain:10
Button ”Density”

Save

Meshgen-2D: FEM Mesh
Toolbar Button: ”Edit FEM Mesh”
Button: Make mesh
Save
Exit

The BOUNDARY Module:

1. Initial Condition:
   Toolbar Button: ”Initial Condition”
   Button ”Select”: Select the entire transport domain
   Button ”Set Value”: check ”equilibrium from the lowest located nodal point.” And set equal to 50.
2. Water Flow Boundary Conditions:
   Toolbar Button: ”Water Flow BC”
   Zoom in on the left furrow.
   1. Select ”Constant pressure”, select bottom of the left furrow and 4 nodes on the side, specify 12 cm with equilibrium from the lowest located nodal point.
      Zoom on the drain.
   2. Select ”Seepage face”: nodes along the drain.
      Default View.
3. Observation Nodes
   Toolbar Button: ”Observation Points”
   Specify 5 points arbitrarily in the transport domain between source and drain
   Save
   Exit

Execute HYDRUS
(Execution time on P5-300 = 566)

OUTPUT:
Menu: Post-Processing ->Observation Points
Menu: Post-Processing ->Boundary Information->Solute Fluxes:
  Seepage face flux
  Cumulative Seepage face flux
Menu: Post-Processing ->Mass Balances Information
Menu: Post-Processing -> Graphical Display of Results
  Pressure heads
  Concentrations