Currents

This part enables you to simulate currents, i.e. water particles moving at a constant velocity in time. It is possible to have a vertical variation of the currents velocity based on a shear power law (see the Currents of the theory manual).
It is also possible to import a current from file and use a user-defined vertical variation of the current velocity.

The word Currents (plural) is used so that it is not confused with the word 'current' in other situations

General

Principal angle

The angle of the currents relative to north (the y-axis). With the currents profile found with the power law, the angle cannot change with depth.

  • Default value: 0
  • Unit: $°$
  • Range: -360 — 360

Surface speed

The horizontal currents speed at the surface.

  • Default value: 2
  • Unit: ${\text{m}} \over {\text{s}}$
  • Range: -∞ — ∞

Ref. depth scheme

A reference depth is used to calculate the reduction in speed by depth. Either the actual depth is used or the user (you) sets the reference depth.
Note: The currents speed is always zero below the reference depth.

Options:

User defined:

The reference depth is set by the user (you). This option is used if a reference depth different from the actual depth should be used.

Actual depth (default):

The actual depth is used as the reference depth.

Ref. depth

The reference depth used to calculate the currents speed.
Note: The currents speed is always zero below the reference depth.


  • Default value: 50
  • Unit: $\text{m}$
  • Range: 0.001 — 1000

Shape exponent

The exponent in the power law used to calculate currents speed. The exponent is minimum 0 and maximum 1. If 0, then the speed is constant (i.e. independent of depth). If 1 then the speed is decreasing linearly with depth (and is 0 at the reference depth).
Note: The currents speed is always zero below the reference depth.

  • Default value: 1
  • Unit: —
  • Range: 0 — 1

Input file

The file that is imported to define the currents profile. If no file is chosen (i.e. if this parameter field is empty) then there is no currents (Note: By default this field is empty).

Note: this parameter is only accessible in the batch manager. In order to import a user-defined current in time simulation, use the Action buttons at the top of the parameter window.


the format of the currents input file is explained in the Currents file section.

  • Default value:
  • Unit: —