PISM, A Parallel Ice Sheet Model  stable v2.0.4 committed by Constantine Khrulev on 2022-05-25 12:02:27 -0800
PatersonBuddCold.cc
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19 
20 #include <cmath>
21 
22 #include "PatersonBuddCold.hh"
23 
24 namespace pism {
25 namespace rheology {
26 
27 PatersonBuddCold::PatersonBuddCold(const std::string &prefix,
28  const Config &config,
30  : PatersonBudd(prefix, config, ec) {
31  m_name = "Paterson-Budd (cold case)";
32 }
33 
34 double PatersonBuddCold::tempFromSoftness(double A) const {
35  return - m_Q_cold / (m_ideal_gas_constant * (log(A) - log(m_A_cold)));
36 }
37 
38 // takes care of hardness...
39 double PatersonBuddCold::softness_from_temp(double T_pa) const {
40  return m_A_cold * exp(-m_Q_cold / (m_ideal_gas_constant * T_pa));
41 }
42 
43 // ignores pressure and uses non-pressure-adjusted temperature
44 double PatersonBuddCold::flow_from_temp(double stress, double temp,
45  double , double) const {
46  return softness_from_temp(temp) * pow(stress,m_n-1);
47 }
48 
49 
50 // Rather than make this part of the base class, we just check at some reference values.
51 bool FlowLawIsPatersonBuddCold(const FlowLaw &flow_law, const Config &config,
53  static const struct {double s, E, p, gs;} v[] = {
54  {1e3, 223, 1e6, 1e-3}, {450000, 475000, 500000, 525000}, {5e4, 268, 5e6, 3e-3}, {1e5, 273, 8e6, 5e-3}};
55  PatersonBuddCold cpb("stress_balance.sia.", config, EC); // This is unmodified cold Paterson-Budd
56  for (int i=0; i<4; i++) {
57  const double left = flow_law.flow(v[i].s, v[i].E, v[i].p, v[i].gs),
58  right = cpb.flow(v[i].s, v[i].E, v[i].p, v[i].gs);
59  if (fabs((left - right)/left)>1.0e-15) {
60  return false;
61  }
62  }
63  return true;
64 }
65 
66 } // end of namespace rheology
67 } // end of namespace pism
A class for storing and accessing PISM configuration flags and parameters.
std::shared_ptr< EnthalpyConverter > Ptr
double m_A_cold
Paterson-Budd softness, cold case.
Definition: FlowLaw.hh:138
double m_Q_cold
Activation energy, cold case.
Definition: FlowLaw.hh:142
std::string m_name
Definition: FlowLaw.hh:116
double flow(double stress, double E, double pressure, double grainsize) const
The flow law itself.
Definition: FlowLaw.cc:89
double m_ideal_gas_constant
ideal gas constant
Definition: FlowLaw.hh:151
double m_n
power law exponent
Definition: FlowLaw.hh:153
double softness_from_temp(double T_pa) const
double tempFromSoftness(double A) const
Return the temperature T corresponding to a given value A=A(T).
PatersonBuddCold(const std::string &prefix, const Config &config, EnthalpyConverter::Ptr EC)
double flow_from_temp(double stress, double temp, double, double) const
The flow law (temperature-dependent version).
Cold case of Paterson-Budd.
Derived class of FlowLaw for Paterson-Budd (1982)-Glen ice.
Definition: PatersonBudd.hh:29
bool FlowLawIsPatersonBuddCold(const FlowLaw &flow_law, const Config &config, EnthalpyConverter::Ptr EC)