Testing Tee Branches (2)

• Stability of models:
  • possible behaviour
    • runs with standard initial conditions
    • runs with special initial conditions
    • doesn't run
  • tests with different boundary conditions
    • pressure at inflow, mass flow at outflow
    • mass flow at inflow, pressure at outflow
    • pressure at inflow and outflow
  • results
    • MFL model works always
    • all TFS models work for simple cases (two mass flows given)
    • basic TFS component works in most non-simple cases
    • other TFS components work never in non-simple-cases
  • problem
    • initialization works always
    • pressure soon rises exponentially
    • differential equations are highly unstable!
    • thorough mathematical investigation needed
• Adding a pipe at straight inflow or outflow:
  • simple cases
    • all TFS work (as before)
    • some MFL models don't work!
  • non-simple cases
    • non-conclusive
    • some MFL models get unstable (don't run)
    • some TFS become stable
  • preliminary conclusion
    • adding pipes destabilizes MFL (larger nonlinear system)
    • adding pipes stabilizes TFS