Trim model where the operating characteristics of rotor (e.g. blade pitch angle) can vary to reach a specified target thrust and torque. More...

#include <targetCoeffTrim.H>

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Public Member Functions
	TypeName ("targetCoeffTrim")
	Run-time type information.
	targetCoeffTrim (const fv::rotorDiskSource &rotor, const dictionary &dict)
	Constructor from rotor and dictionary.
	targetCoeffTrim (const targetCoeffTrim &)=delete
	No copy construct.
void	operator= (const targetCoeffTrim &)=delete
	No copy assignment.
virtual	~targetCoeffTrim ()=default
	Destructor.
void	read (const dictionary &dict)
	Read.
virtual tmp< scalarField >	thetag () const
	Return the geometric angle of attack [rad].
virtual void	correct (const vectorField &U, vectorField &force)
	Correct the model.
virtual void	correct (const volScalarField rho, const vectorField &U, vectorField &force)
	Correct the model for compressible flow.
template<class RhoFieldType>
Foam::vector	calcCoeffs (const RhoFieldType &rho, const vectorField &U, const scalarField &thetag, vectorField &force) const
Public Member Functions inherited from trimModel
	TypeName ("trimModel")
	Run-time type information.
	declareRunTimeSelectionTable (autoPtr, trimModel, dictionary,(const fv::rotorDiskSource &rotor, const dictionary &dict),(rotor, dict))
	trimModel (const fv::rotorDiskSource &rotor, const dictionary &dict, const word &name)
	Construct from components.
virtual	~trimModel ()=default
	Destructor.

Protected Member Functions
template<class RhoFieldType>
vector	calcCoeffs (const RhoFieldType &rho, const vectorField &U, const scalarField &alphag, vectorField &force) const
	Calculate the rotor force and moment coefficients vector.
template<class RhoFieldType>
void	correctTrim (const RhoFieldType &rho, const vectorField &U, vectorField &force)
	Correct the model.

Protected Attributes
label	calcFrequency_
	Number of iterations between calls to 'correct'.
bool	useCoeffs_
	Flag to indicate whether to solve coeffs (true) or forces (false).
vector	target_
	Target coefficient vector (thrust force, roll moment, pitch moment).
vector	theta_
	Pitch angles (collective, roll, pitch) [rad].
label	nIter_
	Maximum number of iterations in trim routine.
scalar	tol_
	Convergence tolerance.
scalar	relax_
	Under-relaxation coefficient.
scalar	dTheta_
	Perturbation angle used to determine jacobian.
scalar	alpha_
	Coefficient to allow for conversion between US and EU definitions.
Protected Attributes inherited from trimModel
const fv::rotorDiskSource &	rotor_
	Reference to the rotor source model.
const word	name_
	Name of model.
dictionary	coeffs_
	Coefficients dictionary.

Additional Inherited Members
Static Public Member Functions inherited from trimModel
static autoPtr< trimModel >	New (const fv::rotorDiskSource &rotor, const dictionary &dict)
	Return a reference to the selected trim model.

Detailed Description

Trim model where the operating characteristics of rotor (e.g. blade pitch angle) can vary to reach a specified target thrust and torque.

Solves:

$\‍[ c^{old} + J.d(\theta) = c^{target} \‍]$

where

	=	Time level
	=	Coefficient vector (thrust force, roll moment, pitch moment)
$\theta$	=	Pitch angle vector (collective, roll, pitch)
	=	Jacobian [3x3] matrix

The trimmed pitch angles are found via solving the above with a Newton-Raphson iterative method. The solver tolerance can be user-input, using the 'tol' entry.

If coefficients are requested (useCoeffs = true), the force and moments are normalised using:

$\‍[ c = \frac{F}{\alpha \pi \rho \omega^2 R^4} \‍]$

and

$\‍[ c = \frac{M}{\alpha \pi \rho \omega^2 R^5} \‍]$

where

	=	Force
	=	Moment
$\alpha$	=	User-input conversion coefficient (default = 1)
$\rho$	=	Fluid desity
$\omega$	=	Rotor angular velocity
$\pi$	=	Mathematical pi
	=	Rotor radius

Usage: Minimal example by using constant/fvOptions: rotorDiskSource1 { Mandatory/Optional (inherited) entries ...

Mandatory entries (runtime modifiable) trimModel targetForce;

targetForceCoeffs { Conditional mandatory entries (runtime modifiable)

when trimModel=targetForce target { Mandatory entries (runtime modifiable) thrust 0.5; pitch 0.5; roll 0.5;

Optional entries (runtime modifiable) useCoeffs true; }

pitchAngles { theta0Ini 0.1; theta1cIni 0.1; theta1sIni 0.1; }

calcFrequency 1;

Optional entries (runtime modifiable) nIter 50; tol 1e-8; relax 1; dTheta 0.1; alpha 1.0; } }

where the entries mean:

Property	Description	Type	Reqd	Dflt
`calcFrequency`	Number of iterations between calls to 'correct'	label	yes	-
`useCoeffs`	Flag to indicate whether to solve coeffs (true) or forces (false)	bool	no	true
`thrust`	Target thrust (coefficient)	scalar	yes	-
`pitch`	Target pitch (coefficient)	scalar	yes	-
`roll`	Target roll moment (coefficient)	scalar	yes	-
`theta0Ini`	Initial pitch angle [deg]	scalar	yes	-
`theta1cIni`	Initial lateral pitch angle (cos coeff) [deg]	scalar	yes	-
`theta1sIni`	Initial longitudinal pitch angle (sin coeff) [deg]	scalar	yes	-
`nIter`	Maximum number of iterations in trim routine	label	no	50
`tol`	Convergence tolerance in trim routine	scalar	no	1e-8
`relax`	Relaxation factor in trim routine	scalar	no	1
`dTheta`	Perturbation angle used to determine Jacobian [deg]	scalar	no	0.1
`alpha`	Coefficient to allow for conversion between US and EU definitions	scalar	no	1

See also

Source files

Definition at line 309 of file targetCoeffTrim.H.

Constructor & Destructor Documentation

◆ targetCoeffTrim() [1/2]

targetCoeffTrim	(	const fv::rotorDiskSource &	rotor,
		const dictionary &	dict )

Constructor from rotor and dictionary.

Definition at line 188 of file targetCoeffTrim.C.

References alpha_, calcFrequency_, Foam::degToRad(), dict, dTheta_, e, Foam::GlobalIOList< Tuple2< scalar, vector > >::typeName, nIter_, read(), relax_, target_, theta_, tol_, trimModel::trimModel(), useCoeffs_, and Foam::Zero.

Referenced by operator=(), and targetCoeffTrim().

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◆ targetCoeffTrim() [2/2]

targetCoeffTrim ( const targetCoeffTrim & )

delete

No copy construct.

References targetCoeffTrim().

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◆ ~targetCoeffTrim()

virtual ~targetCoeffTrim ( )

virtualdefault

Destructor.

References dict, rho, and U.

Member Function Documentation

◆ calcCoeffs() [1/2]

template<class RhoFieldType>

vector calcCoeffs	(	const RhoFieldType &	rho,
		const vectorField &	U,
		const scalarField &	alphag,
		vectorField &	force ) const

protected

Calculate the rotor force and moment coefficients vector.

References rho, and U.

Referenced by correctTrim().

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◆ correctTrim()

template<class RhoFieldType>

void correctTrim	(	const RhoFieldType &	rho,
		const vectorField &	U,
		vectorField &	force )

protected

Correct the model.

Definition at line 94 of file targetCoeffTrim.C.

References calcCoeffs(), calcFrequency_, dTheta_, Foam::endl(), Foam::Info, Foam::inv(), Foam::mag(), nIter_, Foam::nl, Foam::radToDeg(), relax_, rho, trimModel::rotor_, target_, theta_, thetag(), tol_, Foam::type(), U, useCoeffs_, and Foam::Zero.

Referenced by correct(), and correct().

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◆ TypeName()

TypeName ( "targetCoeffTrim" )

Run-time type information.

References dict.

◆ operator=()

void operator= ( const targetCoeffTrim & )

delete

No copy assignment.

References targetCoeffTrim().

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◆ read()

void read ( const dictionary & dict )

virtual

Read.

Reimplemented from trimModel.

Definition at line 211 of file targetCoeffTrim.C.

References alpha_, calcFrequency_, trimModel::coeffs_, Foam::degToRad(), dict, dTheta_, dictionary::get(), dictionary::getOrDefault(), nIter_, trimModel::read(), dictionary::readEntry(), relax_, target_, theta_, tol_, and useCoeffs_.

Referenced by targetCoeffTrim().

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◆ thetag()

Foam::tmp< Foam::scalarField > thetag ( ) const

virtual

Return the geometric angle of attack [rad].

Implements trimModel.

Definition at line 247 of file targetCoeffTrim.C.

References Foam::cos(), forAll, tmp< T >::New(), psi, trimModel::rotor_, Foam::sin(), theta_, and x.

Referenced by calcCoeffs(), and correctTrim().

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◆ correct() [1/2]

void correct	(	const vectorField &	U,
		vectorField &	force )

virtual

Correct the model.

Implements trimModel.

Definition at line 264 of file targetCoeffTrim.C.

References correctTrim(), and U.

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◆ correct() [2/2]

void correct	(	const volScalarField	rho,
		const vectorField &	U,
		vectorField &	force )

virtual

Correct the model for compressible flow.

Implements trimModel.

Definition at line 274 of file targetCoeffTrim.C.

References correctTrim(), rho, and U.

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◆ calcCoeffs() [2/2]

template<class RhoFieldType>

Foam::vector calcCoeffs	(	const RhoFieldType &	rho,
		const vectorField &	U,
		const scalarField &	thetag,
		vectorField &	force ) const

Definition at line 40 of file targetCoeffTrim.C.

References alpha_, cells, forAll, Foam::constant::mathematical::pi(), Foam::pow4(), Foam::reduce(), rho, trimModel::rotor_, Foam::sqr(), thetag(), U, useCoeffs_, x, and Foam::Zero.

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Member Data Documentation

◆ calcFrequency_

label calcFrequency_

protected

Number of iterations between calls to 'correct'.

Definition at line 320 of file targetCoeffTrim.H.

Referenced by correctTrim(), read(), and targetCoeffTrim().

◆ useCoeffs_

bool useCoeffs_

protected

Flag to indicate whether to solve coeffs (true) or forces (false).

Definition at line 325 of file targetCoeffTrim.H.

Referenced by calcCoeffs(), correctTrim(), read(), and targetCoeffTrim().

◆ target_

vector target_

protected

Target coefficient vector (thrust force, roll moment, pitch moment).

Definition at line 330 of file targetCoeffTrim.H.

Referenced by correctTrim(), read(), and targetCoeffTrim().

◆ theta_

vector theta_

protected

Pitch angles (collective, roll, pitch) [rad].

Definition at line 335 of file targetCoeffTrim.H.

Referenced by correctTrim(), read(), targetCoeffTrim(), and thetag().

◆ nIter_

label nIter_

protected

Maximum number of iterations in trim routine.

Definition at line 340 of file targetCoeffTrim.H.

Referenced by correctTrim(), read(), and targetCoeffTrim().

◆ tol_

scalar tol_

protected

Convergence tolerance.

Definition at line 345 of file targetCoeffTrim.H.

Referenced by correctTrim(), read(), and targetCoeffTrim().

◆ relax_

scalar relax_

protected

Under-relaxation coefficient.

Definition at line 350 of file targetCoeffTrim.H.

Referenced by correctTrim(), read(), and targetCoeffTrim().

◆ dTheta_

scalar dTheta_

protected

Perturbation angle used to determine jacobian.

Definition at line 355 of file targetCoeffTrim.H.

Referenced by correctTrim(), read(), and targetCoeffTrim().

◆ alpha_

scalar alpha_

protected

Coefficient to allow for conversion between US and EU definitions.

Definition at line 360 of file targetCoeffTrim.H.

Referenced by calcCoeffs(), read(), and targetCoeffTrim().

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

src/fvOptions/sources/derived/rotorDiskSource/trimModel/targetCoeff/targetCoeffTrim.H
src/fvOptions/sources/derived/rotorDiskSource/trimModel/targetCoeff/targetCoeffTrim.C

Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ targetCoeffTrim() [1/2]

◆ targetCoeffTrim() [2/2]

◆ ~targetCoeffTrim()

Member Function Documentation

◆ calcCoeffs() [1/2]

◆ correctTrim()

◆ TypeName()

◆ operator=()

◆ read()

◆ thetag()

◆ correct() [1/2]

◆ correct() [2/2]

◆ calcCoeffs() [2/2]

Member Data Documentation

◆ calcFrequency_

◆ useCoeffs_

◆ target_

◆ theta_

◆ nIter_

◆ tol_

◆ relax_

◆ dTheta_

◆ alpha_