Section 8 Boundaries and Initial Conditions

Boundary conditions are a crucial part of hydrodynamic modelling, providing the inputs where fluids can enter or leave the hydrodynamic model area. This chapter of the manual discusses the available boundary conditions and the boundary condition database, where constant and time-series of boundary elements are specified. 1D and 2D boundaries are discussed together in this chapter as both access the same boundary database (see Section 8.5), although separate databases can be set up if desired.

The options for applying initial conditions to the 1D and 2D domains of the model are also discussed.

8Boundaries and Initial Conditions

  8.1Recommended BC Arrangements

  8.2Solver Specific Considerations

    8.2.1Classic Specific Boundaries / Options

    8.2.2HPC Specific Boundaries / Options

      8.2.2.1HPC Energy Options for 2D HT, HQ and QT Boundaries

      8.2.2.2HPC HQ Boundary Approach

      8.2.2.3HPC HQ Boundary Stability

      8.2.2.4HPC Additional Boundary Options

      8.2.2.5Quadtree BC Parallel Inertia Approach

  8.31D Boundaries (1d_bc Layers)

  8.42D Boundaries (2d_bc, 2d_sa and 2d_rf Layers)

    8.4.1Boundary Conditions (2d_bc)

      8.4.1.1Sloping Water Level Boundaries

      8.4.1.2Groundwater Boundaries

    8.4.2Source Area Boundaries

      8.4.2.1Source Area Options (2d_sa)

        8.4.2.1.1Streamlines

      8.4.2.2Rainfall Option (2d_sa_rf)

      8.4.2.3Trigger Option (2d_sa_tr)

      8.4.2.4Flow Feature (2d_sa_po)

      8.4.2.5Overlapping 2d_sa regions

    8.4.3Rainfall Boundaries

      8.4.3.1Rainfall Overview

      8.4.3.2Considerations for Rainfall Modelling

      8.4.3.3Global Rainfall

      8.4.3.4Rainfall Polygons (2d_rf)

      8.4.3.5Gridded Rainfall

      8.4.3.6Rainfall Control File (.trfc file)

  8.5Boundary Condition (BC) Database

    8.5.1BC Database Example

    8.5.2TUFLOW Boundary Generators

    8.5.3Delft FEWS Boundaries

    8.5.4HEC-DSS Boundaries

  8.6Cyclones / Hurricanes / Typhoons

  8.7External Stress Boundaries

  8.8Initial Conditions

    8.8.1Initial Water Levels (IWL)

      8.8.1.11D Domains

      8.8.1.22D Domains

      8.8.1.3Automatic Initial Water Level

    8.8.2Initial Groundwater Levels

    8.8.3Restart Files