Flexcom > Data Inputs > $MODEL

Purpose

To specify information relating to a wind turbine, including overall geometry, component masses, and related information.

Theory

Refer to Turbine Geometry for further information.

Keyword Format

A block of lines specifying a variety of information relating to a wind turbine.

OVERHANG=Overhang distance

SHAFT TILT=Shaft tilt angle

TOWER TOP NODE=Tower top node (Number or Label)

TOWER TO SHAFT=Tower to shaft distance

HUB MASS=Hub mass

YAW BEARING MASS=Yaw bearing mass

FRONT BEARING MASS=Shaft front bearing mass

REAR BEARING MASS=Shaft rear bearing mass

HUB BUOYANCY=Hub volume (MHK turbines only), Hub COB X (MHK turbines only), Hub COB Y (MHK turbines only), Hub COB Z (MHK turbines only)

The last two lines, relating to hub and nacelle buoyancy are are only used with MHK turbines. As Flexcom is currently designed to work with wind turbines only, these options are not relevant.

Table Input

Input:	Description
Overhang:	The distance along the (possibly tilted) rotor shaft between the tower centerline and hub center, measured positive downwind. Upwind rotors have a negative overhang. This is illustrated by 'Overhang' in Turbine Geometry and subsequent schematics
Shaft Tilt:	The angle in degrees between the rotor shaft and the horizontal plane. A positive shaft tilt angle means that the downwind end of the shaft is the highest. Upwind turbines have a negative shaft tilt angle for improved tower clearance. This is illustrated by 'ShftTilt' in Turbine Geometry and subsequent schematics.
Tower Top Node:	The location (node number/label) in the finite element model which corresponds to the tower top location.
Tower to Shaft:	The vertical distance from the top of the tower to the shaft axis. This is illustrated by 'Twr2Shft' in Conventional Upwind Turbine Layout.
Hub Mass:	The mass of the hub. This is illustrated by 'Hub C.M.' in Conventional Upwind Turbine Layout.
Yaw Bearing Mass:	The mass of the yaw bearing. This is illustrated by 'Yaw Bearing C.M.' in Conventional Upwind Turbine Layout.
Shaft Front Bearing Mass:	The mass of the front shaft bearing. Note that the front bearing is currently located at a distance along the shaft which is equal to 90% of the overhang distance, in a direction towards the hub from the tower-shaft intersection point.
Shaft Rear Bearing Mass:	The mass of the rear shaft bearing. Note that the rear bearing is currently located at a distance along the shaft which is equal to 20% of the overhang distance, in a direction towards the nacelle from the tower-shaft intersection point.
Hub Volume (MHK turbines only):	The volume of the hub for use in buoyancy computations, a modelling option in OpenFAST for MHK turbines. As Flexcom is currently designed to work with wind turbines only, this input and the subsequent ones relating to centre of buoyancy, are not relevant.
Hub CoB X (MHK turbines only):	The X (downwind) distance from the local origin (tower top / yaw bearing) to the hub centre-of-buoyancy. This input is not relevant and may be left unchanged from the default.
Hub CoB Y (MHK turbines only):	The Y (lateral) distance from the local origin (tower top / yaw bearing) to the hub centre-of-buoyancy. This input is not relevant and may be left unchanged from the default.
Hub CoB Z (MHK turbines only):	The Z (vertical) distance from the local origin (tower top / yaw bearing) to the hub centre-of-buoyancy. This input is not relevant and may be left unchanged from the default.

NotES