Water_level_data
Contents
Data Structure: Water_level_data |
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Description |
Structure defining the water level or free surface |
Usage |
Water_level_data NUM=ival where ival is the data structure number |
Description |
Overview The Water_level_data structure is used to define the sea level or phreatic surface. This is used by the porous fields in the evaluation of the boundary pore pressures and/or saturation. Notes •If Water_level_data is specified the vertical direction must correspond to the Y Direction in 2-D and the Z direction in 3-D. •If stratigraphy is defined (see Stratigraphy_definition) surface pore pressures due to overlying water are automatically computed and any sediment above the water level is assumed to be saturated; i.e. zero surface pore pressure. •Gravity_data must be defined in conjunction with Water_level_data definition. •The water level may change with time by defining a Water_level_curve •A non-horizontal phreatic surface may also be defined by assigning a part-geometry that defines the geometry of the surface. •Only one Water_level_data structure is to be specified at any one stage, however, it can be re-defined at a later stage. In this case, the new data will replace the current data.
Examples Demonstrating the usage of Water_level_data include: None
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 | Water_level Water level value |
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Defines water level as an absolute value. If Relative_level_flag is specified then Water_level indicates the water level relative to the model surface at the reference location. In a problem with sedimentation of new layers the latter option automatically updates the water level after the deposition of each new layer.
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| Water_level_curve Water level vs. time curve |
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Water level vs. time curve. The data is provided as a 2-D table where: •Row 1 - List of time instances in ascending order •Row 2 - Water level at specified times
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| Relative_level_flag Flag indicating that the water level is relative to the surface horizon of model |
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When Relative_level_flag is specified in conjunction with either Water_level or Water_level_curve the water level is assumed to be relative to the surface horizon of the model. The height of the water level is defined as the magnitude specified using Water_level or Water_level_curve plus the model height at the reference location defined via Reference_location. Valid values are: • 0 - Water level is absolute value (default) • 1 - Water level is relative to the surface horizon of model
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| Density Density of overlying fluid (Optional) |
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Description |
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Density of overlying fluid (Optional). If the fluid density is not defined then the density will be evaluated from the fluid properties.
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| Reference_location Reference location for relative water level evaluation |
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Reference location for evaluation of the water level relative to the top surface horizon of the model. The reference location is defined by: •X-ordinate in 2-D, and •X, Y coordinates in 3-D.
Notes •Reference_location is only used if Relative_level_flag = 1. •If the reference location is not specified then it will be taken as the centre of the model.
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| Partial_saturation_flag Flag denoting whether partial saturation is allowed |
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Flag denoting whether partial saturation is allowed. This occurs when the water level is below the top surface of the model. Valid values are: • 0 - Partial saturation is not permitted; i.e. the analysis will terminate with an error message if sediment gets exposed above the water level (default) • 1 - Partial saturation is allowed • 2 - Water level below top surface is allowed but sediment above water level is treated as saturated with zero pore pressure
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| Update_frequency Frequency of the depth update |
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Frequency of the depth update. The default is no update. If an update is required then the recommended values are: •Single field problem with the geomechanical field active (every 100 steps) •Coupled problem with the geomechanical field active (every coupling step)
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