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Wind components

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

The Wind tab includes a radio-button to select the format used to define the wind components, one grid to input the wind parameters, and 2 action buttons to create or remove one row from the grid

The Wind tabs include the following items:

  • Number of winds: The number of individual wind components must be set with the spin box located in the upper right corner of the tab. You may either use the up/down arrows to setup the number of winds, 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 main wind data table with appropriate number of rows.

  • Insert new wind: Pressing this button inserts a new row in the main wind data table.

  • Remove selected wind: Pressing this button deletes the selected rows from the main wind data table.

  • Wind defined through spectrum: This option specifies that wind data are based on wind spectra. The content of the main wind data table is adapted accordingly.

  • Wind defined through time-history squall winds): This option specifies that wind data are based on wind time history recorded at a reference level. This option allows modelling wind velocity and heading variable in time, which allows modelling squall winds. The content of the main wind data table is adapted accordingly.

Definition of wind through wind spectrum

The main wind data table contains several columns with the following headers:

  • Wind name: This assigns names that will be used to refer to the winds components in the Combination matrix tab.

  • Wind heading (deg): This sets the heading (flowing direction) of the wind . Headings are defined for the "to" direction with respect to the global X-axis of the model.

  • Mean velocity: average velocity over a defined time period at the point of interest (m/s). Refer to the Wind component for details on the mean velocity to be considered along with the wind spectrum type.

  • Wind spectrum: Cells in the spectrum column display drop-down lists similar to the drop-down list available in the individual Wind model component. The Squall item is however not included in the list of items. Select the type of spectrum among the following items:

    • Constant: the wind velocity is constant.

    • Harris: the wind velocity follows an Harris spectrum.

    • Davenport: the wind velocity follows a Davenport spectrum.

    • API: the wind velocity follows an API spectrum.

    • NPD: the wind spectrum follows an NPD (Norwegian Petroleum Directory) spectrum.

    • Kaimal: the wind velocity follows an Kaimal spectrum.

  • Number of components: This sets the number of wind harmonic components used to model the wind spectrum. This number of components must be at least 100 (default value) to ensure accurate modeling of the wind energy distribution along frequencies.

  • Random procedure trigger: Phases associated with each wind component are pseudo-random. Phases are generated with a random number generator which requires a certain random procedure trigger (also named "seed") to be user-specified. The trigger value must be an odd integer value with 5 digits (the default value is 11111). Two dynamic simulations based on the same trigger value would generate similar phase series.

The content of the whole table is available for multiple-cells selection and allows copy/paste of data to/from Excel.

Definition of wind through wind time-history

The grid contains 11 columns with the following headers:

  • Wind name: This assigns names that will be used to refer to the winds components in the Combination matrix tab.

  • Type: Select either Squall, FF Wind, or HH wind.

    • Squall winds: This wind type models a squall wind event defined through time-history of wind velocity.

    • FF Wind: This wind type models a full field turbulent wind defined through time-history of wind velocity.

    • HH Wind: This wind type models a hub height wind defined through time-history of wind velocity.

  • Squall wind data:

    • Duration (s): This is the duration of the wind time-history.

    • Beginning time (s): This is the time in the dynamic analysis at which wind loads must be apply.

    • File: Path and name of the external data file providing the time-history of the wind velocity. The path could either be defined by typing the text or by browsing to the file after clicking the button placed on the right hand side of the cells. See the *SQUALLWIND keyword for details on the external file format.

  • FF wind data:

    • Heading /X: The heading (flowing direction) of the wind . Headings are defined for the "to" direction with respect to the global X-axis of the model.

    • Reference position /X: Origin of the file axis in DeepLines Global frame (X direction)

    • Reference position /Y: Origin of the file axis in DeepLines Global frame (Y direction)

    • Time for mirror effect: If the windfile is too short in duration compared to the simulation time, it is possible to use a mirror effect whereby the wind file is played back and forth over the whole simulation time. On the first Time for mirror effect seconds of the simulation, the wind file is used, then it is played backwards over another Time for mirror effect seconds and so on. Only Time for mirror effect seconds of the windfile is used therefore the variable Time for mirror effect should be smaller than the windfile simulation time.

    • File: Path and name of the external file used to define the wind data. A full turbulence field is read by DeepLines. The input data consists of a .sum file (ASCII) and a .wnd file (binary). DeepLines points to the binary file. Both files should be in the same directory.

  • HH wind data:

    • Heading /X: The heading (flowing direction) of the wind . Headings are defined for the "to" direction with respect to the global X-axis of the model.

    • File: Path and name of the external file used to define the wind data. The path to the ASCII file containing the data is provided. See the *WINDFILE keyword for details on the external file format.

    • Reference position /X: Origin of the file axis in DeepLines Global frame (X direction)

    • Reference position /Y: Origin of the file axis in DeepLines Global frame (Y direction)

    • Reference height: Reference Height of the file (usually hub height).

    • Width: Horizontal extend of the wind velocity data included in the file.

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.

Definition of wind through wind time-history

Steady wind: This wind type models a steady wind profile with the velocity and heading being defined function of the height above the sea-level. Input data required to define this wind type are as follows:

  • Quasi-static evolution: Selects the quasi-static loading table. Set the quasi-static evolution to Constant to account for permanent wind loads since the start of the quasi-static analysis. Select Linear evolution to progressively apply the wind loads between the initial and final quasi-static steps of the analysis. Select user-defined evolution to define the ratio of wind velocity that is accounted for as a finction of the quasi-static analysis step.

  • Dynamic evolution: Select either Constant or Variable to define a permanent or variable wind profile. Variable wind profile is defined through series of wind profiles defined at different time values.

  • Steps: Number of vertical positions used to define the wind profile.

  • Height from sea-level / Velocity / Heading: use this table to define the wind profile, i.e. wind velocity and heading as a function of the height above the sea-level.

Warning

Wind loads primarily apply on floater components within coupled mooring analyses. Wind loads have no effect on line components unless drag coefficients in air are specified through the Line Segment type.