vanGenuchten Class Reference

Detailed Description

This module contains the van Genuchten model for the water retention curve.

Version

1.0

Author

Nander Wever

#include <vanGenuchten.h>

Public Types
enum	SoilTypes {   ORGANIC , CLAY , CLAYLOAM , LOAM ,   LOAMYSAND , SAND , SANDYCLAY , SANDYCLAYLOAM ,   SANDYLOAM , SILT , SILTYCLAY , SILTYCLAYLOAM ,   SILTLOAM , WFJGRAVELSAND }
enum	VanGenuchten_ModelTypesSnow { YAMAGUCHI2012 , YAMAGUCHI2010 , YAMAGUCHI2010_ADAPTED , DAANEN }
enum	K_Parameterizations { CALONNE , KOZENYCARMAN , SHIMIZU }

Public Member Functions
	vanGenuchten (ElementData &pEMS)
	Class constructor .
	vanGenuchten (const vanGenuchten &c)
	Copy constructor .
virtual	~vanGenuchten ()
vanGenuchten &	operator= (const vanGenuchten &)
	Assignement operator.
double	fromTHETAtoH (const double theta, const double h_d)
	Calculating pressure head from water content The following function calculates the pressure head belonging to a given water content .
double	fromTHETAtoHforICE (const double theta, const double h_d, const double theta_i)
	Calculating pressure head from water content when ice is present The following function calculates the pressure head belonging to a given water content when ice is present .
double	fromHtoTHETA (const double h)
	Calculating volumetric water content from pressure head The following function calculates the volumetric water content belonging to a given pressure head .
double	fromHtoTHETAforICE (const double h, const double theta_i)
	Calculating volumetric water content from pressure head when ice is present The following function calculates the volumetric water content belonging to a given pressure head when ice is present .
double	dtheta_dh (const double h)
	Specific moisture capacity This function should return exact value of the derivative d.theta / d.h, otherwise RE-solver is unstable. When modifying the water retention curve, for example in the dry limit, the specific moisture capacity function needs to be modified too, to remain an exact derivative. .
void	SetVGParamsSnow (VanGenuchten_ModelTypesSnow VGModelTypeSnow, K_Parameterizations K_PARAM, const bool &matrix, const bool &seaice)
	Initialize van Genuchten model for snow layers .
void	SetVGParamsSoil ()
	Initialize van Genuchten model for soil layers, based on index approach via grain size .
bool	enforceThermalEquilibrium (const bool fixTemp=true)
	Enforce thermal equilibrium in the soil layers .

Static Public Member Functions
static double	AirEntryPressureHead (double MaximumPoreSize, double Temperature)
	Calculate air entry pressure head Air entry pressure head in [m] that corresponds to a maximum pore size (using Young-Laplace Equation). This is a required value for specifying water retention curves, see Ippisch et al. (2006). .

Public Attributes
ElementData *	EMS
double	theta_r
double	theta_s
double	alpha
double	n
double	m
double	h_e
double	Sc
double	ksat
double	field_capacity
bool	defined

Friends
std::iostream &	operator<< (std::iostream &os, const vanGenuchten &data)
std::iostream &	operator>> (std::iostream &is, vanGenuchten &data)

Member Enumeration Documentation

K_Parameterizations

enum vanGenuchten::K_Parameterizations

Enumerator
CALONNE
KOZENYCARMAN
SHIMIZU

SoilTypes

enum vanGenuchten::SoilTypes

Enumerator
ORGANIC
CLAY
CLAYLOAM
LOAM
LOAMYSAND
SAND
SANDYCLAY
SANDYCLAYLOAM
SANDYLOAM
SILT
SILTYCLAY
SILTYCLAYLOAM
SILTLOAM
WFJGRAVELSAND

VanGenuchten_ModelTypesSnow

enum vanGenuchten::VanGenuchten_ModelTypesSnow

Enumerator
YAMAGUCHI2012
YAMAGUCHI2010
YAMAGUCHI2010_ADAPTED
DAANEN

Constructor & Destructor Documentation

vanGenuchten() [1/2]

vanGenuchten::vanGenuchten

(

ElementData &

pEMS

)

Class constructor
.

Author

Nander Wever

Parameters

pEMS	pointer to the ElementData class which owns the van Genuchten class, so the van Genuchten class can access objects from the ElementData class.

vanGenuchten() [2/2]

vanGenuchten::vanGenuchten

(

const vanGenuchten &

c

)

Copy constructor
.

Author

Nander Wever

Parameters

c	Class to copy

~vanGenuchten()

virtual vanGenuchten::~vanGenuchten ( )

inlinevirtual

Member Function Documentation

AirEntryPressureHead()

double vanGenuchten::AirEntryPressureHead ( double  MaximumPoreSize, double  Temperature  )

static

Calculate air entry pressure head
Air entry pressure head in [m] that corresponds to a maximum pore size (using Young-Laplace Equation).
This is a required value for specifying water retention curves, see Ippisch et al. (2006).
.

Author

Nander Wever

Parameters

MaximumPoreSize	Maximum pore size (diameter, not radius!) [m]
Temperature	Temperature for determining surface tension [K]

dtheta_dh()

double vanGenuchten::dtheta_dh

(

const double

h

)

Specific moisture capacity
This function should return exact value of the derivative d.theta / d.h, otherwise RE-solver is unstable. When modifying the water retention curve, for example in the dry limit, the specific moisture capacity function needs to be modified too, to remain an exact derivative.
.

Author

Nander Wever

Parameters

h	Pressure head (m)

enforceThermalEquilibrium()

bool vanGenuchten::enforceThermalEquilibrium

(

const bool

fixTemp = true

)

Enforce thermal equilibrium in the soil layers
.

Parameters

fixTemp

If true, keep element temperature fixed and repartition theta[ICE] and theta[WATER]. If false, keep theta[ICE] and theta[WATER] fixed, and calculate element temperature. The latter approach is prone to singularities. For example, a soil layer with a temperature below Constants::meltfreeze_tk, but with only water and no ice, cannot be properly initialized (i.e., there is no solution that satisfies thermal equilibrium).

Returns

True: element state was modified by this function, false: element state was not modified by this function

Author

Nander Wever

fromHtoTHETA()

double vanGenuchten::fromHtoTHETA

(

const double

h

)

Calculating volumetric water content from pressure head
The following function calculates the volumetric water content belonging to a given pressure head
.

Author

Nander Wever

Parameters

h	Pressure head (m)

fromHtoTHETAforICE()

double vanGenuchten::fromHtoTHETAforICE	(	const double	h,
		const double	theta_i
	)

Calculating volumetric water content from pressure head when ice is present
The following function calculates the volumetric water content belonging to a given pressure head when ice is present
.

Author

Nander Wever

Parameters

h	Pressure head (m)
theta_i	Ice content (m^3/m^3)

fromTHETAtoH()

double vanGenuchten::fromTHETAtoH	(	const double	theta,
		const double	h_d
	)

Calculating pressure head from water content
The following function calculates the pressure head belonging to a given water content
.

Author

Nander Wever

Parameters

theta	Water content (m^3/m^3)
h_d	Dry limit of pressure head

fromTHETAtoHforICE()

double vanGenuchten::fromTHETAtoHforICE	(	const double	theta,
		const double	h_d,
		const double	theta_i
	)

Calculating pressure head from water content when ice is present
The following function calculates the pressure head belonging to a given water content when ice is present
.

Author

Nander Wever

Parameters

theta	Water content (m^3/m^3)
h_d	Dry limit of pressure head
theta_i	Ice content (m^3/m^3)

operator=()

vanGenuchten & vanGenuchten::operator=

(

const vanGenuchten &

source

)

Assignement operator.

Assignment operator
.

Author

Nander Wever

Parameters

source

Class to assign

SetVGParamsSnow()

void vanGenuchten::SetVGParamsSnow	(	VanGenuchten_ModelTypesSnow	VGModelTypeSnow,
		K_Parameterizations	K_PARAM,
		const bool &	matrix,
		const bool &	seaice
	)

Initialize van Genuchten model for snow layers
.

Author

Nander Wever

Parameters

VGModelTypeSnow	van Genuchten model parameterization to use
K_PARAM	hydraulic conductivity parameterization to use
matrix	true: set parameters for matrix domain. false: set parameters for preferential flow domain
seaice	if true: use some tweaks for sea ice.

SetVGParamsSoil()

void vanGenuchten::SetVGParamsSoil

(

)

Initialize van Genuchten model for soil layers, based on index approach via grain size
.

Author

Nander Wever

Friends And Related Symbol Documentation

operator<<

std::iostream & operator<< ( std::iostream &  os, const vanGenuchten &  data  )

friend

operator>>

std::iostream & operator>> ( std::iostream &  is, vanGenuchten &  data  )

friend

Member Data Documentation

alpha

double vanGenuchten::alpha

defined

bool vanGenuchten::defined

EMS

ElementData* vanGenuchten::EMS

field_capacity

double vanGenuchten::field_capacity

h_e

double vanGenuchten::h_e

ksat

double vanGenuchten::ksat

m

double vanGenuchten::m

n

double vanGenuchten::n

Sc

double vanGenuchten::Sc

theta_r

double vanGenuchten::theta_r

theta_s

double vanGenuchten::theta_s

---

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

• vanGenuchten.h
• vanGenuchten.cc