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ADH Model

AD aptive H ydraulics Modeling System Single Computational Engine for Navier -Stokes, Saturated Groundwater, and Shallow-water Equations Unstructured Platform Portability Multi-Physics Conservation Adaption. ADH Model.

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ADH Model

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  1. ADaptiveHydraulics Modeling System • Single Computational Engine for Navier-Stokes, Saturated Groundwater, and Shallow-water Equations • Unstructured • Platform Portability • Multi-Physics • Conservation • Adaption ADH Model

  2. Hydrodynamic model that engineers use routinely in rivers and estuaries. Development Philosophy • Navigation • Flood Control • Environmental Restoration

  3. Structure Design GIWW Michoud Canal Structure Inset Bayou Bienvenue MRGO Proposed GIWW Structure Velocity Results (m/s)

  4. Levee Breach Case Study New Orleans, USA

  5. Dune Overwash Case Study

  6. 3D Hydraulics Case Study Lower Monumental Lock and Dam Washington, USA

  7. 3D Hydraulics Case Study 8100 ft of Snake River Reach 3300 ft wide @ widest section Structural Features: Lock Guard Wall, 8 Spillway Bays, & 6 Powerhouse Unit

  8. 3D Hydraulics Case Study

  9. Baroclinic Transport Mobile Bay Alabama, USA

  10. Sediment Transport Bed Displacement Suspended Sediment

  11. Research Versions: • 3D Hydrodynamics • Groundwater Interaction • Constituent Transport • Sediment Transport ADH Model Development Public Release v4.1: • 2D Hydrodynamics • Baroclinic Transport (Salinity & Temperature)

  12. Variable time step: Time step determined by physics • Super and subcritical flow • Wetting and Drying: Shock Capturing • Adaption: Dynamic element refinement • Flow Control Structures: bridge decks, spillways, weirs, gates • Bendway correction: 3D effects of vorticity around bends ADH-2D Key Features

  13. Mesh Construction and Mesh Quality • Defining material properties • Specifying Time and Model Control parameters • Assigning Boundary Conditions • Defining Control Structures • Setting Initial Conditions ADH Model Setup

  14. Mesh Resolution 182 Elements 1200 Elements 4800 Elements 19200 Elements Initial Concentration

  15. Mesh Resolution Computed Concentration @ 380 seconds

  16. Adaption Computed Concentration Time Lapse with Adaption

  17. Adaption Example Adaption around a moving vessel

  18. Mesh−Element Quality Poor Element Quality Improved Element Quality

  19. Element Quality

  20. Element Quality Tips Less Desirable Better Preferred

  21. Bed Roughness: • Manning’s n • Roughness height • Vegetation Eddy Viscosity: • Estimated • Kinematic Material Properties

  22. Dynamic vs. Steady State • Automatic vs. Specified Time Steps • Output Interval Time Controls Initial time step guidance:

  23. Subcritical • Inflow: Total Discharge, Unit Flow, or Vx & Vy • Outflow: Water Surface Elevation Supercritical • Inflow: Vx, Vy, and Depth • Outflow: Free flow Flow Boundary Conditions

  24. Flow Control Structures Decks (Lid) Nodestrings & Nodes (Assign BC) Spillway  Nodestrings (NB SPL Card) Weirs Nodestrings (WER & WRS Cards) Flap Gates Nodestrings (FLP & FGP Cards)

  25. Rainfall and Evaporation Elements (Material Properties) Wind Friction  Stations (Spatial Data Coverage) Ice Friction  Elements (ICE & IRH cards) Sidewall Friction Nodestrings (Assign BC) Other Boundary Conditions

  26. Constant WSE recommended for cold start • Include velocity only when hotstarting from an ADH solution • Major contributing factor for model success Initial Conditions Guidance

  27. ADH Model Execution • Pre-ADH • ADH • PC LVL card for additional screen output Nonlinear Iteration Max Residual Node ID Failure Flag # Nodes Physics Time Step Percent Completion Linear Iteration Max Increment Norm Node ID Time (sec)

  28. ADH Solution Files

  29. Build Mesh • Mesh Quality • Material Properties • Time Control Parameters • Boundary Conditions • Initial Conditions • Renumber • Save Project & Launch ADH ADH Checklist

  30. The Modeling Process Data Collection Network Design Model Application Model Debugging Testing & Calibration F e e d b a c k L o o p

  31. Mesh geometry • Voids? • Poorly formed elements? • Reasonable resolution? • Are the elements aligned with flow direction and wetting/drying boundary? Troubleshooting

  32. Boundary conditions • Is the water level below elevation of nodes? • Are your initial conditions consistent with your boundary conditions? • Supercritical flow? • Is the initial depth zero for a significant portion of the domain? Troubleshooting

  33. Model parameters • Adjust DTL (shock capturing parameter) – rule of thumb is 5% of average depth. • Adjust time steps • Try switching the tolerance used to determine convergence (NTL/ITL) • Increase the maximum number of iterations (don’t go higher than 10) Troubleshooting

  34. Try running a steady state simulation (STD card) and using the resulting depths/velocities as a hotstart for the dynamic run • Check the solver (in .bc file) if you are using multiple processors or blocks • Try allowing ADH to automatically compute time steps (ATF card) Other Troubleshooting Tips

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