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Current components

The Current tab defines a list of individual current profiles that may be used to define combined environments from the Combination matrix tab.

Current profiles may be varied function of the quasi-static analysis step. However, unless standard current profiles included in the current data form, these components can not be set to vary function of time.

The Current tab includes the following items:

  • Number of profiles: The number of individual profiles components must be set with the spin box located in the upper left corner of the tab. You may either use the up/down arrows to setup the number of profiles, or input any value using your keyboard and then pressing the ENTER key. Pressing the ENTER key confirms the number of individual components to be included and generates the profiles names table and profiles data table with appropriate number of rows and columns.

  • Current headings: This option allows selecting whether the heading of each current profile is to be set constant over the water column (i.e. plane current profiles), or if it is to be set variable over the water column (i.e. current profiles sheared in direction).

  • Current profile names table: This table is used to assign names that will be used to refer to the current profiles in the Combination matrix tab. This table also defines the headings (i.e. "to" direction with respect to the global X-axis of the model) of the currents in case the headings of every current profiles are set constant over the water column.

  • Quasi-static evolution: This option allows selecting how the current profile is to be applied over the quasi-static analyses. "Constant" means that the current profile is fully applied at the first quasi-static step (i.e. step 0). "Linear" means that the current profile is applied progressively with a linear ramp between the first quasi-static step (i.e. no current loads at step 0)and the last quasi-static step (i.e. full current loads at the last quasi-static step). "User defined" allows selecting the rate of velocity that is considered as a function of the quasi-static step. Wake shielding and dipole effects may also be considered. Refer to the Current model component for details.

    Hint

    It is recommended that you use the "Linear" quasi-static evolution as a base case to help convergence of the quasi-static analysis. "Constant" quasi- static evolution may indeed raise convergence issues at the first quasi-static step with high velocity profiles.

  • Depth steps: This sets the number of Z positions at which the current velocity and direction are specified.

  • Current profiles data table: This table defines the velocity and heading as a function of the Z position.

    • Water depth: This sets the Z positions at which the current velocity and direction are specified. Note that the values input there must be negative since they refer to the vertical Z position (and not to the actual depth).

    • Velocity: This sets the velocity of the current profile as a function of the Z position.

    • Heading: This sets the heading (flowing direction) of the current profile as a function of the Z position. Headings are defined for the "to" direction with respect to the global X-axis of the model. Note that the heading data can be input in this table only in case the heading of each current profile is set variable over the water column (i.e. current profiles sheared in direction).

Note

The content of the tables included in this data form allows selection of multiple-cells and copy/paste of data to/from Excel using the CTRL+C and CTRL+V keys. The whole content of any table may be selected by clicking any cell in the table and further pressing the CTRL+A keys.

An example of Current tab is illustrated below: