Inheritance diagram for CableElBasics:

Collaboration diagram for CableElBasics:

Public Member Functions
	CableElBasics ()
	The constructor.

	~CableElBasics ()
	The destructor.

virtual void	AddEndForces (const double adPosA[3], const double adVelA[3], const double adPosB[3], const double adVelB[3], const double adFluidVel[3], const double rhoWater, double adForceA[3], double adForceB[3])
	Calculates the end forces on the cable element.

virtual void	SetConstants ()
	Calculates parameters and sets physical constants.

virtual void	CalcMassAndWeight ()
	Calculates the mass and weight of the element in water.

virtual bool	CheckAndInitialize ()
	Does the initialization and checking to make sure that the element is ready for simulation.

double	GetDampingCoeff () const
	Returns the structural damping coefficient (negative value: -2dampRatioareasqrt(Erho)).

virtual void	UpdateLength (double newLength)
	Upates the length of the cable element, and its dependant properties.

double	GetLength ()

void	SetSurfaceElevation (double etaA, double etaB)

virtual double	SurfaceHalfSize () const
	The half-size the surface gate needs: the element's radius; larger with floats (NetCableElement).

void	SetWaveAcceleration (const double acceleration[3])

double	InertiaShare () const
	The inertia force factor of one end node: half of (1 + Ca) rho V f (environment::cylinder_hydro::InertiaForceFactor).

void	WaveExcitationPositionJacobian (const double posA[3], const double posB[3], const double acceleration[3], double dF_dpB[9]) const

Public Attributes
unsigned long	m_iD
	The ID of the element.

std::string	m_cableName
	The name of the parent cable.

double	m_dL0
	The relaxed length of the element.

double	m_dD
	The diameter of the element.

double	m_dE
	The Young modulus of the element.

double	m_rho
	The density of the element material.

double	m_addedWeightInWater
	The weight in water added to the element.

double	m_tangentialFrictionCoeff
	The tangential drag coefficient of the cable element.

double	m_normalDragCoeff
	The normal drag coefficient of the cable element.

double	m_rhoWater
	The density of the surrounding fluid: the water density blended with the air density by the submerged fraction (CalcFoundation).

double	m_rhoAir = 1.2
	The air density, kg/m³; the owner sets the environment's (cable_air::EnvironmentAirDensity, owner ruling R65).

double	m_minLength
	The minimum length of the element.

double	m_maxTension
	The maximum tension in the element.

double	m_dampingRatio
	The relative damping ratio of the cable.

double	m_eA
	The linear stiffness of the element.

double	m_dA
	The cross sectional area of the cable.

double	m_weightInWater [2]
	The weight in water distributed to each node.

double	m_massInWater [2]
	The mass in water distributed to each node.

double	m_weightInWaterPerMeter [2]
	The weight in water distributed to each node, per meter cable.

double	m_massInWaterPerMeter [2]
	The mass in water distributed to each node, per meter cable.

Static Public Attributes
static constexpr double	kAddedMassCoefficient = environment::cylinder_hydro::kCylinderAddedMassCoefficient

Protected Member Functions
virtual bool	AppendagesNearTheSurface ()
	True when a float on the element is near the surface, so its weight must be recomputed every call; none here.

void	AddWaveExcitationCable (double adForceA[3], double adForceB[3]) const
	Adds the rope's Froude-Krylov and added-mass wave excitation (owner rulings R67, R104). CalcFoundation must be run first.

void	CalcFoundation (const double adPosA[3], const double adVelA[3], const double adPosB[3], const double adVelB[3], const double adFluidVel[3], const double rhoWater)

virtual void	AddStructuralForces (double adForceA[3], double adForceB[3])
	Adds the forces from tension and internal damping to the nodes. CalcFoundation must be run first.

void	AddGravityBuoyancy (double adForceA[3], double adForceB[3], const double adPosA[3], const double adPosB[3])
	Adds the forces from gravity and buoyancy to the nodes. CalcFoundation must be run first.

void	AddHydroForcesCable (double adForceA[3], double adForceB[3])
	Calculates the hydrodynamic forces on the cable and the spheres and disks attached to it. CalcFoundation must be run first.

Protected Attributes
double	m_surfaceElevation [2] = {0.0, 0.0}
	η above the ends [m] (SetSurfaceElevation).

double	m_submergence [2] = {1e10, 1e10}
	z + η at the ends at the last CalcFoundation [m]; deep before the first.

double	m_axisVertical = 0.0
	The vertical component of the unit axis A→B at the last CalcFoundation.

double	m_wetFraction = 1.0
	The element's wet fraction at the last CalcFoundation (CylinderWetFraction).

double	m_rhoWaterFull = 1025.0
	The water density the owner passed, unblended [kg/m³].

double	m_waveAcceleration [3] = {0.0, 0.0, 0.0}
	The water particle acceleration at the element (SetWaveAcceleration) [m/s²].

double	ma_adDirection [3]
	Memory allocation to increase the computational efficiency.

double	ma_dDampingCoeff
	A intermediate damping calculation to increase the computational efficiency.

double	ma_adVel [3]
	The average hydrodynamic velocity of the element.

double	ma_dVelAmp
	The scalar average hydrodynamic velocity of the element.

double	ma_adVt [3]
	The average tangential hydrodynamic velocity of the element.

double	ma_dVtAmp
	The scalar average tangential hydrodynamic velocity of the element.

double	ma_adVn [3]
	The average normal hydrodynamic velocity of the element.

double	ma_dVnAmp
	The scalar average normal hydrodynamic velocity of the element.

double	ma_adVn_A [3]
	The hydrodynamic normal velocity of the end A.

double	ma_adVn_B [3]
	The hydrodynamic normal velocity of the end B.

double	ma_dVnAmp_A
	The scalar hydrodynamic normal velocity of the end A.

double	ma_dVnAmp_B
	The scalar hydrodynamic normal velocity of the end B.

double	ma_dLength
	The actual distance between the ends.

double	ma_dCompressionSpeed
	The speed at which the distance between the two ends decreases.

double	ma_dTangentialDragFactor
	A factor used when calculating the tangential drag force.

double	ma_dNormalDragFactor
	A factor used when calculating the normal drag force.

Member Function Documentation

◆ AddStructuralForces()

virtual void CableElBasics::AddStructuralForces	(	double	adForceA[3],
		double	adForceB[3]
	)

protectedvirtual

Reimplemented in CableElDynStiff.

◆ AppendagesNearTheSurface()

virtual bool CableElBasics::AppendagesNearTheSurface ( )

inlineprotectedvirtual

Reimplemented in NetCableElement, and NetCableElementWithConstraints.

◆ CalcFoundation()

void CableElBasics::CalcFoundation	(	const double	adPosA[3],
		const double	adVelA[3],
		const double	adPosB[3],
		const double	adVelB[3],
		const double	adFluidVel[3],
		const double	rhoWater
	)

protected

Calculates the member variables used for increased computational efficiency, and must be run before any further calculations.

◆ CalcMassAndWeight()

virtual void CableElBasics::CalcMassAndWeight ( )

virtual

Reimplemented in NetCableElement, and NetCableElementWithConstraints.

◆ CheckAndInitialize()

virtual bool CableElBasics::CheckAndInitialize ( )

virtual

Reimplemented in CableElDynStiff, NetCableElement, and NetCableElementWithConstraints.

◆ SetConstants()

virtual void CableElBasics::SetConstants ( )

virtual

Reimplemented in NetCableElement, and NetCableElementWithConstraints.

◆ SetSurfaceElevation()

void CableElBasics::SetSurfaceElevation	(	double	etaA,
		double	etaB
	)

inline

Sets the surface elevation η above the two ends for the next force evaluations (owner ruling R66).

The owner evaluates η at the ends, or passes 0 where the element is deeper, or higher, than the maximum wave elevation plus SurfaceHalfSize() (then the fraction is the same).

Parameters

etaA	η above end A [m], positive up.
etaB	η above end B [m].

◆ SetWaveAcceleration()

void CableElBasics::SetWaveAcceleration ( const double acceleration[3] )

inline

Sets the water particle acceleration at the element for the next force evaluations (owner rulings R67, R104); 0 by default, so an owner without waves adds nothing.

Parameters

acceleration The acceleration [m/s²], NED.

◆ SurfaceHalfSize()

virtual double CableElBasics::SurfaceHalfSize ( ) const

inlinevirtual

Reimplemented in NetCableElement, and NetCableElementWithConstraints.

◆ WaveExcitationPositionJacobian()

void CableElBasics::WaveExcitationPositionJacobian	(	const double	posA[3],
		const double	posB[3],
		const double	acceleration[3],
		double	dF_dpB[9]
	)		const

The derivative of the rope's wave excitation (AddWaveExcitationCable) in the position of end B through the turning of the element's axis (owner ruling R108), for an analytical Jacobian. The force is the same on both ends, and its derivative in end A is the negative. The wet fraction is the last CalcFoundation's, and the gradient of the wave field and of the wet fraction are left out, as the drag's current gradient is.

Parameters

posA	End A [m], NED.
posB	End B [m], NED.
acceleration	The water particle acceleration at the element [m/s²], NED.
dF_dpB	Out: dF[j]/dpB[k] at [3 * j + k] [N/m].

Member Data Documentation

◆ kAddedMassCoefficient

constexpr double CableElBasics::kAddedMassCoefficient = environment::cylinder_hydro::kCylinderAddedMassCoefficient

staticconstexpr

The added-mass coefficient of the rope normal to its axis: a circular cylinder, Ca = 1 (DNV-RP-C205 (2021), Appendix A, Table A-1; the table was not checked here). The element's inertia (rho_c + rho) A L (CalcMassAndWeight) carries the same Ca, in every direction.

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

webfhsim/reloadrepos/fhsim_marine_elements/src/cable/subroutines/CableElBasics.h

Public Member Functions

Public Attributes

Static Public Attributes

Protected Member Functions

Protected Attributes

Member Function Documentation

◆ AddStructuralForces()

◆ AppendagesNearTheSurface()

◆ CalcFoundation()

◆ CalcMassAndWeight()

◆ CheckAndInitialize()

◆ SetConstants()

◆ SetSurfaceElevation()

◆ SetWaveAcceleration()

◆ SurfaceHalfSize()

◆ WaveExcitationPositionJacobian()

Member Data Documentation

◆ kAddedMassCoefficient