Date post: | 19-Dec-2015 |
Category: |
Documents |
View: | 217 times |
Download: | 0 times |
Free vs. Forced Convection FEFLOW® Exercise
Spatial Discretization
• Automatic mesh generation (~3000 triangular elements)• Mesh refinement (via Rubberbox and Border Options)
FEFLOW Mesh Generation
Height approx. 100 m
Free vs. Forced Convection FEFLOW® Exercise
Model Set-up
FEFLOW Basic Settings
• 2D (default)
• Problem Class:Flow and Mass (steady flow, transient
transport)
• Vertical problem projection
• Temporal and control data:Automatic time stepping, FE/BE time
integrationFinal time: 36500 days (100 years)
Free vs. Forced Convection FEFLOW® Exercise
Flow Problem - Material parameters
• Global: Density ratio = 10-3
Input 10 [10-4]
Model Set-up
p C o 1
p po– Cs Co– ----------------------- C Co– + +=
Cs
o–o
--------------------------=
Free vs. Forced Convection FEFLOW® Exercise
Flow Problem - Boundary Conditions
• Impermeable border (default)
• 1st-kind boundary condition at an arbitrary node, e.g., upper left: h = 0 m
Model Set-up
Free vs. Forced Convection FEFLOW® Exercise
Mass-Transport Problem - Boundary Conditions
Implemented as 1st-kind boundary condition in the center section of the upper border (via Border-Option)
Concentration at the spill site: 100 mg/l
• C = 100 mg/l
Model Set-up
Free vs. Forced Convection FEFLOW® Exercise
Numerical Solution
FEFLOW Options
• Direct equation solver
Free vs. Forced Convection FEFLOW® Exercise
Model Extension
Flow Problem - Boundary Conditions
Horizontal hydraulic gradient (‘strong’)
Implemented as 1st-kind boundary condition along the left and right vertical borders(via Border-Option):
• left side: h = 0 m• right side:h = 0.1 m
Free vs. Forced Convection FEFLOW® Exercise
FEFLOW Result
Flow is dominated by forced horizontal convection
Numerical Solution
Free vs. Forced Convection FEFLOW® Exercise
Reducing the boundary-condition value on the right vertical border (via Debug option):
• right side:h = 0.01 m
Model Modification
Flow Problem - Boundary Conditions
Horizontal hydraulic gradient (‘weak’)