Mooring

The mooring system ontology follows closely the input file format for MoorDyn or MAP++. Additional information can be found in the MoorDyn user guide .

        nodes:
            - name: line1_anchor
              node_type: fixed
              joint: anchor1
              anchor_type: drag_embedment
            - name: line2_anchor
              node_type: fixed
              joint: anchor2
              anchor_type: drag_embedment
            - name: line3_anchor
              node_type: fixed
              joint: anchor3
              anchor_type: drag_embedment

            - name: line1_vessel
              node_type: vessel
              joint: col1_fairlead
              fairlead_type: rigid
            - name: line2_vessel
              node_type: vessel
              joint: col2_fairlead
              fairlead_type: rigid
            - name: line3_vessel
              joint: col3_fairlead
              node_type: vessel
              fairlead_type: rigid

        lines:
            - name: line1
              node1: line1_anchor
              node2: line1_vessel
              line_type: main
              unstretched_length: 850.0
            - name: line2
              node1: line2_anchor
              node2: line2_vessel
              line_type: main
              unstretched_length: 850.0
            - name: line3
              node1: line3_anchor
              node2: line3_vessel
              line_type: main
              unstretched_length: 850.0

        line_types:
            - name: main
              diameter: 0.185
              type: chain
              transverse_added_mass: 1.0
              tangential_added_mass: 0.0
              transverse_drag: 1.6
              tangential_drag: 0.1

        anchor_types:
            - name: drag_embedment
              type: drag_embedment

nodes

nameString

Name or ID of this node for use in line segment

node_type : String from, [‘fixed’, ‘connection’, ‘vessel’]

locationArray of Floats, meter

– Coordinates x, y, and z of the connection (relative to inertial reference frame if Fixed or Connect, relative to platform reference frame if Vessel). In the case of Connect nodes, it is simply an initial guess for position before MoorDyn calculates the equilibrium initial position.

anchor_typeString

Name of anchor type from anchor_type list

fairlead_type : String from, [‘rigid’, ‘actuated’, ‘ball’]

node_massFloat, kilogram

Clump weight mass

Minimum = 0.0

node_volumeFloat, meter^3

Floater volume

Minimum = 0.0

drag_areaFloat, meter^2

Product of drag coefficient and projected area (assumed constant in all directions) to calculate a drag force for the node

Minimum = 0.0

added_massFloat

Added mass coefficient used along with node volume to calculate added mass on node

lines

nameString

ID of this line

line_typeString

Reference to line type database

unstretched_lengthFloat, meter

length of line segment prior to tensioning

Minimum = 0.0

node1String

node id of first line connection

node2String

node id of second line connection

line_types

nameString

Name of material or line type to be referenced by line segments

diameterFloat, meter

the volume-equivalent diameter of the line – the diameter of a cylinder having the same displacement per unit length

Minimum = 0.0

mass_densityFloat, kilogram/meter

mass per unit length (in air)

Minimum = 0.0

stiffnessFloat, Newton

axial line stiffness, product of elasticity modulus and cross- sectional area

Minimum = 0.0

costFloat, USD/meter

cost per unit length

Minimum = 0.0

breaking_loadFloat, Newton

line break tension

Minimum = 0.0

dampingFloat, Newton * second

internal damping (BA)

transverse_added_massFloat

transverse added mass coefficient (with respect to line displacement)

Minimum = 0.0

tangential_added_massFloat

tangential added mass coefficient (with respect to line displacement)

Minimum = 0.0

transverse_dragFloat

transverse drag coefficient (with respect to frontal area, d*l)

Minimum = 0.0

tangential_dragFloat

tangential drag coefficient (with respect to surface area, π*d*l)

Minimum = 0.0

anchor_types

nameString

Name of anchor to be referenced by anchor_id in Nodes section

massFloat, kilogram

mass of the anchor

Minimum = 0.0

costFloat, USD

cost of the anchor

Minimum = 0.0

max_lateral_loadFloat, Newton

Maximum lateral load (parallel to the sea floor) that the anchor can support

Minimum = 0.0

max_vertical_loadFloat, Newton

Maximum vertical load (perpendicular to the sea floor) that the anchor can support

Minimum = 0.0