HydroGeoSphere/Tile Drains

Tile drains, as outlined in Section 2.3.2.3, can be set up using the following instructions. Currently, this option requires that the system be variably-saturated. Default Tile Drain Properties The default tile drain values, Table 5.9, can be and are recommended to be modified to fit the model application. +Table 5.9Table 5.9: Default Values for Tile Drain Properties Parameter Value Unit Screen Radius 1 × 10−5 m Coupled Conductivity 7.438 × 10−5 m s−1 Coupled Length 1 × 10−4 m Coupled Scheme Shared - Tile Drain Type Hagen-Poiseuille - Manning's Friction Coefficient 0.0548 m−1/3 s Hazen Williams Coefficient 130 m0.37 s−1 • • • Example Tile Drain Instructions As an example, the following set of instructions, with prefix.tprops file Figure 5.13, could be inserted into the prefix.grok file to produce a horizontal tile drain: use domain type tile properties file prefix.tprops clear chosen segments choose segments polyline !Screen interval 2 15. 1. 2. 15. 29. 2. new zone 1 clear chosen zones choose zone number 1 read properties tile one clear chosen nodes choose node !Tile drain intake 15. 15. 2. create node set tile boundary condition type flux nodal name tile one node set tile time value table 0.0 -2 !Pumping duration and rate end end The tile domain example opens the property file prefix.tprops, shown in Figure 5.13, and creates a 28 m long screen between (15, 1, 2) and (15, 29, 2) with a pump intake located at (15, 15, 2). The tile one properties are read into grok and a steady pumping rate is set at -2 m3 s−1. Figure 5.13 !------------------------------------------ tile one radius 0.0108 !Coupling length and conductivity for dual node approach coupling length 1.0e-4 coupling conductivity .0023 !Infilled tiled drain with properties from the mprops file infilled Porous medium end Figure 5.13: Sample tile drain domain property file prefix.tprops • • • Radius Scope: .grok .wprops TileScreenRadius Tile drain screen radius [L]. The radius of the screen interval of the tile drain. • • • Infilled Scope: .grok .wprops This command should be included in the input file for an infilled tile drain. • • • Hagen Poiseuille Scope: .grok .wprops This command should be included in the input for the Hagen Poiseuille flow option. • • • Hazen Williams Scope: .grok .wprops This command should be included in the input file for the Hazen Williams flow option. • • • Manning Scope: .grok .wprops This command should be included in the input file for the Manning flow option. • • • Friction Scope: .grok .wprops tile_friction Manning’s friction for tile drains. • • • Hazen Williams coefficient Scope: .grok .wprops tile_hw_coeffient Hazen-Williams coefficient for tile drains. • • • Dual nodes for tiles Scope: .grok .wprops This instruction causes the tile drain flow scheme to use dual node approach. • • • Coupling conductivity Scope: .grok .wprops TilePropsCplCond Coupling conductivity for tile [L T−1]. Coupling conductivity parameter only required for the dual node approach for tile drains. • • • Coupling length Scope: .grok .wprops TilePropsCplLngth Coupling length for tile drain [L]. Coupling length parameter only required for the dual node approach for tile drains. • • •