RichardsSeffVG Class Reference

Utility functions for van-genuchten effective saturation as a function of porepressure (not capillary pressure), and first and second derivs wrt porepressure. More...

#include <RichardsSeffVG.h>

Static Public Member Functions
static Real	seff (Real p, Real al, Real m)
	effective saturation as a fcn of porepressure More...
static Real	dseff (Real p, Real al, Real m)
	derivative of effective saturation wrt porepressure More...
static Real	d2seff (Real p, Real al, Real m)
	2nd derivative of effective saturation wrt porepressure More...

Detailed Description

Utility functions for van-genuchten effective saturation as a function of porepressure (not capillary pressure), and first and second derivs wrt porepressure.

So seff = 1 for p >= 0. seff < 1 for p < 0.

Definition at line 21 of file RichardsSeffVG.h.

Member Function Documentation

d2seff()

Real RichardsSeffVG::d2seff ( Real  p, Real  al, Real  m  )

static

2nd derivative of effective saturation wrt porepressure

Parameters

p	porepressure
al	van-genuchten alpha parameter
m	van-genuchten m parameter

Definition at line 45 of file RichardsSeffVG.C.

Referenced by RichardsSeff2gasVG::d2seff(), RichardsSeff2waterVG::d2seff(), RichardsSeff1VG::d2seff(), RichardsSeff2gasVGshifted::d2seff(), and RichardsSeff2waterVGshifted::d2seff().

{
  if (p >= 0)
    return 0.0;
  else
  {
    Real n = 1.0 / (1.0 - m);
    Real inner = 1 + std::pow(-al * p, n);
    Real dinner_dp = -n * al * std::pow(-al * p, n - 1);
    Real d2inner_dp2 = n * (n - 1) * al * al * std::pow(-al * p, n - 2);
    Real d2seff_dp2 = m * (m + 1) * std::pow(inner, -m - 2) * std::pow(dinner_dp, 2) -
                      m * std::pow(inner, -m - 1) * d2inner_dp2;
    return d2seff_dp2;
  }
}

dseff()

Real RichardsSeffVG::dseff ( Real  p, Real  al, Real  m  )

static

derivative of effective saturation wrt porepressure

Parameters

p	porepressure
al	van-genuchten alpha parameter
m	van-genuchten m parameter

Definition at line 30 of file RichardsSeffVG.C.

Referenced by RichardsSeff2gasVG::dseff(), RichardsSeff2waterVG::dseff(), RichardsSeff1VG::dseff(), RichardsSeff2waterVGshifted::dseff(), RichardsSeff2gasVGshifted::dseff(), and RichardsSeff1VGcut::RichardsSeff1VGcut().

{
  if (p >= 0)
    return 0.0;
  else
  {
    Real n = 1.0 / (1.0 - m);
    Real inner = 1 + std::pow(-al * p, n);
    Real dinner_dp = -n * al * std::pow(-al * p, n - 1);
    Real dseff_dp = -m * std::pow(inner, -m - 1) * dinner_dp;
    return dseff_dp;
  }
}

seff()

Real RichardsSeffVG::seff ( Real  p, Real  al, Real  m  )

static

effective saturation as a fcn of porepressure

Parameters

p	porepressure
al	van-genuchten alpha parameter
m	van-genuchten m parameter

Definition at line 15 of file RichardsSeffVG.C.

Referenced by RichardsSeff1VGcut::RichardsSeff1VGcut(), RichardsSeff2gasVGshifted::RichardsSeff2gasVGshifted(), RichardsSeff2waterVGshifted::RichardsSeff2waterVGshifted(), RichardsSeff2waterVG::seff(), RichardsSeff2gasVG::seff(), RichardsSeff1VG::seff(), RichardsSeff2gasVGshifted::seff(), and RichardsSeff2waterVGshifted::seff().

{
  Real n, seff;

  if (p >= 0)
    return 1.0;
  else
  {
    n = 1.0 / (1.0 - m);
    seff = 1 + std::pow(-al * p, n);
    return std::pow(seff, -m);
  }
}

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

• richards/include/utils/RichardsSeffVG.h
• richards/src/utils/RichardsSeffVG.C