Classes
class	linalg_error

class	LinearInterpolator

class	no_convergence_error

class	no_solution_found

class	physics_error

class	pressure_range_error

struct	stringbuilder

class	temperature_range_error

Functions
double	calcGasThermalConductivity (const double pressure)
	Calculate thermal conductivity of natural gas at given pressure. More...

double	calcOuterWallFilmCoefficient (const double diameter, const AmbientFluid &fluid)
	Calculate outer film coefficient for a given outer diameter and AmbientFluid. More...

double	calcOuterWallFilmCoefficient (const double diameter, const double heatCapacityConstantPressure=4200, const double viscosity=1.05/1000.0, const double thermalConductivity=0.57, const double density=1020, const double velocity=0.1)
	Calculate the outer film coefficient for external flow normal to a circular cylinder. More...

double	calcInnerWallFilmCoefficient (const double diameter, const double fluidPressure, const double fluidReynoldsNumber, const double fluidHeatCapacityConstantPressure, const double fluidViscosity)
	Calculate inner wall film coefficient for flow inside a cylinder. More...

double	calcEquivalentBurialLayerWidth (const double innerDiameter, const double wallThickness, const double burialDepth, const double burialMediumConductivity=2.0)
	Calculate equivalent burial layer thickness. More...

double	calcEquivalentBurialLayerRadius (const double innerDiameter, const double wallThickness, const double burialDepth, const double burialMediumConductivity=2.0)
	calcEquivalentBurialLayerRadius More...

arma::vec	calcLogSpacedShellWidths (const double innerRadius, const double outerRadius, const arma::uword nShells=10)
	Calculate logarithmically (log10) spaced cylinder shell widths. More...

arma::vec	calcEquivalentBurialLayerWidths (const double innerDiameter, const double wallThickness, const double burialDepth, const double burialMediumConductivity=2.0, const arma::uword nShells=10)
	Calculate the widths of equivalent burial cylinder shells. More...

arma::vec	tridag (const arma::vec &a, const arma::vec &b, const arma::vec &c, const arma::vec &r, const arma::uword n)

double	calculateHeatCapacityConstantVolumeJFH (const double pressure)

double	calculateHeatCapacityConstantVolumeTGNet (const double molarMass, const double pressure, const double temperature)

double	calculateHeatCapacityConstantPressureJFH (const double molarMass, const double pressure, const double temperature)

double	calculateHeatCapacityConstantPressureLangelandsvik (const double molarMass, const double pressure, const double temperature)

double	calculateHeatCapacityConstantPressureTGNet (const double molarMassOfMixture, const double pressure, const double temperature)

double	calculateHeatCapacityConstantPressureKIO (const Composition &comp, const double pressure, const double temperature)

double	calculateIsobaricHeatCapacityJKH (const Composition &comp, const double pressure, const double temperature, const double Z=0)

arma::vec	calculateViscosity (const arma::vec &molarMass, const arma::vec &temperature, const arma::vec &density)

arma::vec	calculateReynoldsNumber (const arma::vec &massFlow, const arma::vec &diameter, const arma::vec &viscosity)

arma::vec	calculateColebrookWhiteFrictionFactor (const arma::vec &sandGrainEquivalentRoughness, const arma::vec &diameter, const arma::vec &reynoldsNumber)

double	calculateColebrookWhiteFrictionFactor (const double sandGrainEquivalentRoughness, const double diameter, const double reynoldsNumber)

double	calculateHaalandFrictionFactor (const double sandGrainEquivalentRoughness, const double diameter, const double reynoldsNumber)

double	pow2 (const double a)

arma::vec	pow2 (const arma::vec &a)

double	pow3 (const double a)

double	pow4 (const double a)

double	pow5 (const double a)

double	pow6 (const double a)

arma::vec	cubeRoot (const arma::vec &input)

arma::vec	centerDifference (const arma::vec &input)

arma::vec	centerDifference (const arma::subview_col< arma::mat::elem_type > &input)

arma::vec	centerSum (const arma::vec &input)

arma::vec	centerSum (const arma::subview_col< arma::mat::elem_type > &input)

arma::vec	centerAverage (const arma::vec &input)

arma::vec	centerAverage (const arma::subview_col< arma::mat::elem_type > &input)

arma::vec	weightedAverage (const arma::vec &weightA, const arma::vec &weightB, const arma::vec &A, const arma::vec &B)

double	weightedAverage (const double weightA, const double weightB, const double A, const double B)

bool	isRelativeDifferenceWithinTolerance (const double oldValue, const double newValue, const double tolerance)

bool	areRelativeDifferencesWithinTolerance (const arma::vec &oldValues, const arma::vec &newValues, const double tolerance)

double	convertBurialToStandardDefinition (const double burial, const double innerDiameter, const arma::rowvec &width)

double	convertBurialToStandardDefinition (const double burial, const double innerDiameter, const arma::subview_row< arma::mat::elem_type > &width)

arma::vec	convertBurialToStandardDefinition (const arma::vec &burial, const arma::vec &innerDiameter, const arma::colvec &width)

arma::vec	convertBurialToStandardDefinition (const arma::vec &burial, const arma::vec &innerDiameter, const arma::mat &width)

arma::vec	smooth (const arma::vec &x, const double smoothness)

arma::vec	smoothTransition (const arma::vec &firstPart, const arma::vec &lastPart, double smoothness=1.0, const double timeStep=60)

arma::vec	createSmoothTransient (const double initialValue, const double finalValue, const arma::uword n, const double smoothness, const arma::uword dt)

arma::vec	findLogSpacedConcentricShellWidths (const double innerRadius, const double outerRadius, const arma::uword nShells)

arma::cube	loadCubeFromFile (const std::string &filename, const arma::file_type &fileType=arma::csv_ascii)

arma::mat	loadMatFromFile (const std::string &filename, const arma::file_type &fileType=arma::csv_ascii)

arma::vec	loadVecFromFile (const std::string &filename, const arma::file_type &fileType=arma::csv_ascii)

Detailed Description

Namespace for some utilities.

Function Documentation

◆ calcEquivalentBurialLayerRadius()

double utils::calcEquivalentBurialLayerRadius	(	const double	innerDiameter,
		const double	wallThickness,
		const double	burialDepth,
		const double	burialMediumConductivity = `2.0`
	)

calcEquivalentBurialLayerRadius

For a pipeline buried in a medium at a given depth, this function calculates the outer radius of an equivalent cylinder shell of the same medium around the pipeline which gives the same heat transfer between the fluid in the pipeline and the ambient medium. The calculation is based on equations in the documentation of the OLGA simulation software.

Parameters

innerDiameter	Pipeline inner diameter [m]
wallThickness	Pipeline wall thickness [m]
burialDepth	Distance from top of pipe to top of burial medium [m]
burialMediumConductivity	Thermal conductivity of burial medium [W/(m K)]

Returns: Outer radius of equivalent cylinder shell of burial medium [m]

◆ calcEquivalentBurialLayerWidth()

double utils::calcEquivalentBurialLayerWidth	(	const double	innerDiameter,
		const double	wallThickness,
		const double	burialDepth,
		const double	burialMediumConductivity = `2.0`
	)

Calculate equivalent burial layer thickness.

For a pipeline buried in a medium at a given depth, this function calculates the thickness of an equivalent cylinder shell of the same medium around the pipeline which gives the same heat transfer between the fluid in the pipeline and the ambient medium. The calculation is based on equations in the documentation of the OLGA simulation software.

Using the thickness from this function ensures the same results are achieved with steady state and unsteady heat transfer models.

See also: utils::calcEquivalentBurialLayerRadius()

Parameters

innerDiameter	Pipeline inner diameter [m]
wallThickness	Pipeline wall thickness [m]
burialDepth	Distance from top of pipe to top of burial medium [m]
burialMediumConductivity	Thermal conductivity of burial medium [W/(m K)]

Returns

◆ calcEquivalentBurialLayerWidths()

arma::vec utils::calcEquivalentBurialLayerWidths	(	const double	innerDiameter,
		const double	wallThickness,
		const double	burialDepth,
		const double	burialMediumConductivity = `2.0`,
		const arma::uword	nShells = `10`
	)

Calculate the widths of equivalent burial cylinder shells.

This is just a wrapper around utils::calcEquivalentBurialLayerRadius() and utils::calcLogSpacedShellWidths() that divides the shell into several logarithmically spaced shells.

See also: utils::calcEquivalentBurialLayerRadius(); utils::calcLogSpacedShellWidths()

Parameters

innerDiameter	Inner diameter [m]
wallThickness	Wall thickness [m]
burialDepth	Distance from top of pipe to top of burial medium [m]
burialMediumConductivity	Thermal conductivity of burial medium [W/(m K)]
nShells	Number of shells

Returns: Widths of logarithmically spaced cylinder shells.

◆ calcGasThermalConductivity()

double utils::calcGasThermalConductivity ( const double pressure )

Calculate thermal conductivity of natural gas at given pressure.

This is some kind of empirical relation or fitting, with an unknown source. It should probably be replaced with something else. See for example A simple correlation to estimate natural gas thermal conductivity (Azad Jarrahiana and Ehsan Heidaryan, Journal of Natural Gas Science and Engineering, Volume 18, May 2014).

Parameters

pressure Gas pressure [Pa].

Returns: Thermal conductivity [W/(m K)]

◆ calcInnerWallFilmCoefficient()

double utils::calcInnerWallFilmCoefficient	(	const double	diameter,
		const double	fluidPressure,
		const double	fluidReynoldsNumber,
		const double	fluidHeatCapacityConstantPressure,
		const double	fluidViscosity
	)

Calculate inner wall film coefficient for flow inside a cylinder.

This uses the Dittus-Boelter equation at Reynolds numbers abve 1e4, eq. 8.55 Fundamentals of heat and mass transfer (7th Ed, 2011) (Bergman, Lavine, Incropera, DeWitt) at Reynolds number between 1e4 and 4e4, and returns 0 below 4e4.

Parameters

diameter	Inner diameter [m]
fluidPressure	Fluid pressure [Pa]
fluidReynoldsNumber	Fluid Reynolds number [-]
fluidHeatCapacityConstantPressure	Fluid heat capacity ( \(c_p\)) [J/(kg K)]
fluidViscosity	Fluid dynamic viscosity [Pa s] = [kg/m*s]

Returns: Inner film coefficient [W/(m2 K)]

◆ calcLogSpacedShellWidths()

arma::vec utils::calcLogSpacedShellWidths	(	const double	innerRadius,
		const double	outerRadius,
		const arma::uword	nShells = `10`
	)

Calculate logarithmically (log10) spaced cylinder shell widths.

This function calculates the widths of nShells cylinder shells, logarithmically (log10) spaced between innerRadius and outerRadius.

Parameters

innerRadius	Inner radius [m]
outerRadius	Outer radius [m]
nShells	Number of cylinder shells

Returns: arma::vec of shell widths [m]

◆ calcOuterWallFilmCoefficient() [1/2]

double utils::calcOuterWallFilmCoefficient	(	const double	diameter,
		const AmbientFluid &	fluid
	)

Calculate outer film coefficient for a given outer diameter and AmbientFluid.

This is just a wrapper around utils::calcOuterWallFilmCoefficient(const double, const double, const double, const double, const double, const double)

Parameters

diameter	Outer diameter [m]
fluid	AmbientFluid describing the fluid

Returns: Outer film coefficient [W/(m2 K)]

◆ calcOuterWallFilmCoefficient() [2/2]

double utils::calcOuterWallFilmCoefficient	(	const double	diameter,
		const double	heatCapacityConstantPressure = `4200`,
		const double	viscosity = `1.05/1000.0`,
		const double	thermalConductivity = `0.57`,
		const double	density = `1020`,
		const double	velocity = `0.1`
	)

Calculate the outer film coefficient for external flow normal to a circular cylinder.

Uses eq. 7.52 from Fundamentals of heat and mass transfer (7th Ed, 2011) (Bergman, Lavine, Incropera, DeWitt).

Parameters

diameter	Outer diameter [m]
heatCapacityConstantPressure	Fluid heat capacity ( \(c_p\)) [J/(kg K)]
viscosity	Fluid dynamic viscosity [Pa s] = [kg/m*s]
thermalConductivity	Fluid thermal conductivity [W/(m K)]
density	Fluid density [kg/m3]
velocity	Fluid velocity [m/s]

Returns: Outer film coefficient [W/(m2 K)]

Classes

Functions

Detailed Description

Function Documentation

◆ calcEquivalentBurialLayerRadius()

◆ calcEquivalentBurialLayerWidth()

◆ calcEquivalentBurialLayerWidths()

◆ calcGasThermalConductivity()

◆ calcInnerWallFilmCoefficient()

◆ calcLogSpacedShellWidths()

◆ calcOuterWallFilmCoefficient() [1/2]

◆ calcOuterWallFilmCoefficient() [2/2]