Inheritance diagram for CCable:

Collaboration diagram for CCable:

Classes
struct	SegmentJacobian
	Derivatives of one segment's node forces FA and FB, each a row-major [3 x 3] matrix. More...

struct	SegmentSample

Public Member Functions
	CCable (const std::string &simObjectName, ISimObjectCreator *const creator)
	Reads parameters, registers states, input/output ports and shared resources.

void	OdeFcn (const double T, const double const X, double const XDot) const
	free allocated memory

void	InitialConditionSetup (const double T, const double const currentIC, double const updatedIC, ISimObjectCreator *const creator)
	Sets initial conditions based on the value of input ports.

void	FinalSetup (const double T, const double const X, ISimObjectCreator const creator)

void	PreOdeFcn (const double T, const double const X, IStateUpdater const updater) override
	retrieves pointer to environment object

const double *	ForceA (const double T, const double *const X)

const double *	ForceB (const double T, const double *const X)
	output port. See PortDefs.h. Returns force at point A

void	computeEndForces (const double T, const double *const X) const
	output port. See PortDefs.h. Returns force at point B

void	computeEndpoints (const double T, const StateFrame &frame) const
	computes free nodes and both end forces

bool	HasJacobians () const override

void	OdeJacobian (double T, const double X, double J, int nStates) override

int	GetJacobianSparsity (int nStates, int rowPtr, int colIdx) override

Protected Member Functions
void	computeSegmentForces (const double T, int segment, const double X, const double pA, const double pB, const double vA, const double vB, double FA, double FB, double waveBound, double wetOut=nullptr, bool *inSeabedContactOut=nullptr) const
	Computes all forces acting on an element.

double	nodeMass (double wetHalves) const

double	waveInertiaCoefficient () const
	(1 + Ca) rho A L of a segment, the factor of the wave excitation on the normal particle acceleration (R67).

std::optional< double >	surfaceElevation (const double T, const double pA, const double pB, double waveBound) const

double	wetFraction (const double pA, const double pB, std::optional< double > seaElevation, double dWet_dpA=nullptr, double dWet_dpB=nullptr) const

void	computeVirtualPoint (const double const target, const double const point, const double const targetVel, const double const pointVel, double virtualPoint, double virtualPointVel, double residual, double dResidual) const
	Computes position and velocity of the virtual point.

void	testPositiveParam (double value, ISimObjectCreator *creator, std::string valueName)

SegmentSample	sampleSegment (const double T, int segment, const double pA, const double pB, double waveBound, bool withWetDerivatives) const

void	segmentForces (const SegmentSample &sample, const double pA, const double pB, const double vA, const double vB, double FA, double FB, double wetOut=nullptr, bool inSeabedContactOut=nullptr) const
	computeSegmentForces of a segment already sampled; `pA` and `pB` are the positions it was sampled at.

void	computeSegmentJacobian (const double T, int segment, const double pA, const double pB, const double vA, const double vB, SegmentJacobian &jac, double waveBound) const
	Computes the derivatives of all forces computeSegmentForces differentiates: structural and drag.

void	segmentJacobian (const SegmentSample &sample, const double pA, const double pB, const double vA, const double vB, SegmentJacobian &jac) const
	computeSegmentJacobian of a segment sampled with the wetted fraction's derivatives.

void	addSegmentHydrodynamicJacobian (const SegmentSample &sample, const double vA, const double vB, SegmentJacobian &jac) const

Protected Attributes
double	m_cableLength

double	m_cableWeight
	total cable length [m]

double	m_Emodulus
	cable weight [kg/m]

double	m_tensileCrossSectionArea
	Young's modulus of load bearing material [Pa].

double	m_displacementCrossSectionArea
	cross section area of load bearing material [m^2]

double	m_diameter
	displaced fluid volume per meter cable [m^2]

double	m_hydrodynamicDiameter
	cable diameter [m]

double	m_submergedWeight
	effective hydrodynamic diameter [m]

double	m_waterDensity
	weight of cable underwater [kg/m]

double	m_internalDamping
	water density, the parameter Rho [kg/m^3]

int	m_numElements
	structural axial damping. [N*s/m]

double	m_elementMass
	number of elements in the cable [#]

double	m_segmentMass
	mass of each free node: its two half-segments, one segment's mass (R96) [kg]

double	m_segmentSubmergedMass
	mass of each segment [kg]

double	m_segmentLength
	submerged weight of each element [kg]

double	m_segmentStiffness
	length of spring between elements [m]

int *	m_elementPositionIndex
	spring stiffness [N/m]

int *	m_elementVelocityIndex
	The relative index of the position state in the state array for each element [#].

int	m_stateBase = 0
	The relative index of the velocity state in the state array for each element [#].

ISignalPort *	m_PositionA

ISignalPort *	m_PositionB
	input port. Position of point A [m]

ISignalPort *	m_VelocityA
	input port. Position of point B [m]

ISignalPort *	m_VelocityB
	input port. Velocity of point A [m/s]

ISignalPort *	m_retractedLengthPortA
	input port. Velocity of point B [m/s]

ISignalPort *	m_retractedLengthPortB
	amount of retracted cable at endpoint A [m]

ISignalPort *	m_retractedSpeedPortA
	amount of retracted cable at endpoint B [m]

ISignalPort *	m_retractedSpeedPortB
	retraction rate at endpoint A [m/s]

double	m_endForceA [3]
	retraction rate at endpoint B [m/s]

double	m_endForceB [3]
	reactive force at endpoint A [N]

double	m_nodeForceA [3]
	reactive force at endpoint A [N]

double	m_nodeForceB [3]
	force on first free node at endpoint A [N]

double	m_wetEndA = 1.0
	force on first free node at endpoint A [N]

double	m_wetEndB = 1.0
	wetted fraction of the segment from virtual point A to the first free node

std::vector< double >	m_nodeWetHalves
	wetted fraction of the segment from the last free node to virtual point B

double	m_retractedLengthA
	per node, the summed wetted fractions of its two half-segments

double	m_retractedLengthB
	amount of retracted cable at endpoint A [m]

int	m_retractedNodesA
	amount of retracted cable at endpoint B [m]

int	m_retractedNodesB
	number of nodes currently on winch A

double	m_virtualPointA [3]
	number of nodes currently on winch B

double	m_virtualPointB [3]
	when cable is winched, the closest free node is attracted towards a ghost point "beyond" the actual endpoint [m]

double	m_virtualPointVelocityA [3]
	when cable is winched, the closest free node is attracted towards a ghost point "beyond" the actual endpoint [m]

double	m_virtualPointVelocityB [3]
	when cable is winched, the closest free node is attracted towards a ghost point "beyond" the actual endpoint [m/s]

double	m_residualA
	when cable is winched, the closest free node is attracted towards a ghost point "beyond" the actual endpoint [m/s]

double	m_residualB
	free length of closest free node [m]

ICommonComputation *	m_computeEndForces
	free length of closest free node [m]

const double *	m_posA
	computation node for endpoint reaction forces

const double *	m_posB
	Position of point A [m].

const double *	m_velA
	Position of point B [m].

const double *	m_velB
	Velocity of point A [m].

environment::wake::ElementFlowInteraction	m_flow
	Velocity of point B [m].

environment::EnvironmentProvider *	m_environment
	m_flow's Environment, from FinalSetup.

environment::SeafloorForcesInterface *	m_seafloorForces = nullptr
	The shared resource `SeafloorForces`, from FinalSetup.

bool	m_endSegmentsInSeabedContact = false
	Whether either end segment was in contact at the last end-force computation.

bool	m_inSeabedContact = false
	Whether any segment was in contact at the last OdeFcn: the cable has no Jacobian then.

Static Protected Attributes
static constexpr int	kLiveSegment = -1
	test if a parameter is positive, and reports error if not.

Constructor & Destructor Documentation

◆ CCable()

CCable::CCable	(	const std::string &	simObjectName,
		ISimObjectCreator *const	creator
	)

This constructor performs all initial setup for a point mass simobject. Reading in parameters, setting up communication interface i.e. output ports, input ports, and states, plus additional 'one time only' resource setup.

Parameters

[in]	simObjectName	-> The name of the simobject. Used primarily by superclass constructor
[in]	creator	-> Retrieve parameters. Register states, ports and shared resources

Member Function Documentation

◆ addSegmentHydrodynamicJacobian()

void CCable::addSegmentHydrodynamicJacobian	(	const SegmentSample &	sample,
		const double *	vA,
		const double *	vB,
		SegmentJacobian &	jac
	)		const

protected

Adds the derivatives of one segment's wetted-fraction terms to jac: the buoyancy and the drag's factor, the wetted fraction, w.r.t. both node positions (R66), and the drag w.r.t. both node velocities and, through the segment direction, both node positions.

◆ computeEndpoints()

void CCable::computeEndpoints	(	const double	T,
		const StateFrame &	frame
	)		const

Computes the retracted nodes, residual lengths and virtual endpoints.

Parameters

[in]	T	Current simulation time
[in]	frame	The state vector: the input ports are read at frame.Global(), the nodes at frame.State()

◆ computeSegmentForces()

void CCable::computeSegmentForces	(	const double	T,
		int	segment,
		const double *	X,
		const double *	pA,
		const double *	pB,
		const double *	vA,
		const double *	vB,
		double *	FA,
		double *	FB,
		double	waveBound,
		double *	wetOut = `nullptr`,
		bool *	inSeabedContactOut = `nullptr`
	)		const

protected

Computes structural and environmental forces acting on an element i.e. the cable length between two cable nodes, and distributes the total force on the two nodes.

Parameters

[in]	T	-> current simulation time
[in]	segment	-> the segment's index: that of its node B, numElements for the one to endpoint B (the sample point of PreOdeFcn); kLiveSegment samples the flow live
[in]	X	-> current simulation state
[in]	pA	-> position of element A
[in]	pB	-> position of element B
[in]	vA	-> velocity of element A
[in]	vB	-> velocity of element B
[out]	FA	-> force on element A
[out]	FB	-> force on element B
[in]	waveBound	-> EnvironmentFacade::MaxWaveElevation() of the environment, taken once per evaluation
[out]	wetOut	-> the wetted fraction of the segment; null to skip
[out]	inSeabedContactOut	-> whether the segment is in contact with the seabed; null to skip

◆ computeVirtualPoint()

void CCable::computeVirtualPoint	(	const double *const	target,
		const double *const	point,
		const double *const	targetVel,
		const double *const	pointVel,
		double *	virtualPoint,
		double *	virtualPointVel,
		double	residual,
		double	dResidual
	)		const

protected

Winch functionality is implemented by pulling the closest free node towards a virtual point rather than the actual endpoint.

Parameters

[in]	target	-> actual endpoint position
[in]	point	-> position of free node
[in]	targetVel	-> actual endpoint velocity
[in]	pointVel	-> velocity of free node
[in]	residual	-> free element length
[in]	dResidual	-> rate of change in free element length
[out]	virtualPoint	-> position of virtual point
[out]	virtualPointVel	-> velocity of virtual point

◆ InitialConditionSetup()

void CCable::InitialConditionSetup	(	const double	T,
		const double *const	currentIC,
		double *const	updatedIC,
		ISimObjectCreator *const	creator
	)

Sets initial conditions based on the value of input ports. Element positions of free nodes are equally distributed between endpoint positions. Element Velocity are linearly interpolated between endpoint velocity

Parameters

[in]	T	-> The time at the beginning of the simulation. Usually but not necessarily zero
[in]	currentIC	-> Array of initial conditions. If the value is QNAN, the value is not set yet and can be set by the SimObject, otherwise the value is set, and can not be changed. Trying to change an already set value will trigger an error
[in]	creator	-> Report back to creator if output port are not ready
[out]	updatedIC	-> Array of ONAN. Any initial condition that are ready to be set, should be written to this array.

◆ nodeMass()

double CCable::nodeMass ( double wetHalves ) const

protected

A free node's mass: its own, plus the added mass Ca rho A L times wetHalves, the summed wetted fractions of its two half-segments (R93, BASE-0068).

◆ OdeFcn()

void CCable::OdeFcn	(	const double	T,
		const double *const	X,
		double *const	XDot
	)		const

Computes object derivatives as a function of time, states and input ports

Returns state derivatives. Velocity as derivative of position, external-force/mass and gravity as derivative of velocity. Adjusts position of not-free nodes.

Parameters

[in]	T	-> current simulation time
[in]	X	-> current simulation state
[out]	XDot	-> state derivatives
[in]	bIsMajorTimeStep	-> Is this a major time step?

◆ PreOdeFcn()

void CCable::PreOdeFcn	(	const double	T,
		const double *const	X,
		IStateUpdater *const	updater
	)

override

Takes the other objects' wakes at the segment midpoints for the step (MARE-0223 of fhsim_marine_elements, owner ruling R-c): the segment forces of the step read the held composition, applied to the live current at the segment in each evaluation (fhsim_environment's ElementFlowInteraction, ExternalWakeUpdate).

Parameters

[in]	T	Time of the step start [s].
[in]	X	The global state vector; null does nothing.
[in]	updater	Unused.

◆ sampleSegment()

SegmentSample CCable::sampleSegment	(	const double	T,
		int	segment,
		const double *	pA,
		const double *	pB,
		double	waveBound,
		bool	withWetDerivatives
	)		const

protected

Samples the geometry and the environment for the segment from pB to pA.

Parameters

withWetDerivatives Also fill jacobianWet, dWet_dpA and dWet_dpB.

◆ surfaceElevation()

std::optional< double > CCable::surfaceElevation	(	const double	T,
		const double *	pA,
		const double *	pB,
		double	waveBound
	)		const

protected

The wave elevation over a segment's midpoint, one wave sum (owner ruling R66, BASE-0058).

Parameters

[in]	T	Current simulation time.
[in]	pA	Position of node A.
[in]	pB	Position of node B.
[in]	waveBound	EnvironmentFacade::MaxWaveElevation() of the environment.

Returns: The elevation, or none without evaluating it when the whole segment is below every trough.

◆ wetFraction()

double CCable::wetFraction	(	const double *	pA,
		const double *	pB,
		std::optional< double >	seaElevation,
		double *	dWet_dpA = `nullptr`,
		double *	dWet_dpB = `nullptr`
	)		const

protected

The fraction of a segment's displaced volume that is in water (owner ruling R66, BASE-0058).

Parameters

[in]	pA	Position of node A.
[in]	pB	Position of node B.
[in]	seaElevation	surfaceElevation of the segment; none: below every trough, the fraction is 1.
[out]	dWet_dpA	Optional: d fraction / d pA, with the wave elevation taken as given.
[out]	dWet_dpB	Optional: d fraction / d pB, likewise.

Returns: environment::body_submergence::CylinderWetFraction of a cylinder of the nominal diameter between the two nodes, under the wave surface taken flat at seaElevation; with the derivatives, the value of CylinderWetFractionGradient, which may differ from it in the last bits.

Member Data Documentation

◆ kLiveSegment

constexpr int CCable::kLiveSegment = -1

staticconstexprprotected

What the geometry and the environment give for one segment at one time, the common input of computeSegmentForces and addSegmentHydrodynamicJacobian.

Q is the unit vector from node B to node A (zero for a segment with no length). The wetted fraction is known always; the quantities after it are only sampled for a wetted segment, and the current only where the segment is not deeper below the seabed than the cable is thick. OdeJacobian samples each segment once, with the derivatives, for its forces and its Jacobian (BASE-0064). The segment index of computeSegmentForces for a flow sampled live, not from the per-step take (tests).

◆ m_flow

environment::wake::ElementFlowInteraction CCable::m_flow

protected

The flow at the segment midpoints, the other objects' wakes taken per step (MARE-0223); the Environment, from FinalSetup.

◆ m_stateBase

int CCable::m_stateBase = 0

protected

Global index of this object's first state, element0_position; cached in the constructor.

The documentation for this class was generated from the following file:

webfhsim/reloadrepos/fhsim_base/src/cable/Cable.h

Classes

Public Member Functions

Protected Member Functions

Protected Attributes

Static Protected Attributes

Constructor & Destructor Documentation

◆ CCable()

Member Function Documentation

◆ addSegmentHydrodynamicJacobian()

◆ computeEndpoints()

◆ computeSegmentForces()

◆ computeVirtualPoint()

◆ InitialConditionSetup()

◆ nodeMass()

◆ OdeFcn()

◆ PreOdeFcn()

◆ sampleSegment()

◆ surfaceElevation()

◆ wetFraction()

Member Data Documentation

◆ kLiveSegment

◆ m_flow

◆ m_stateBase