opm-simulators/TransportSolverTwophaseAd.cpp
2013-05-07 13:32:59 +02:00

260 lines
11 KiB
C++

/*
Copyright 2013 SINTEF ICT, Applied Mathematics.
This file is part of the Open Porous Media project (OPM).
OPM is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
OPM is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with OPM. If not, see <http://www.gnu.org/licenses/>.
*/
#include "TransportSolverTwophaseAd.hpp"
#include <opm/core/grid.h>
#include <opm/core/linalg/LinearSolverInterface.hpp>
#include <opm/core/pressure/tpfa/trans_tpfa.h>
#include <opm/core/utility/parameters/ParameterGroup.hpp>
#include <opm/core/utility/ErrorMacros.hpp>
#include <iostream>
namespace Opm
{
/// Construct solver.
/// \param[in] grid A 2d or 3d grid.
/// \param[in] props Rock and fluid properties.
/// \param[in] linsolver Linear solver for Newton-Raphson scheme.
/// \param[in] gravity Gravity vector (null for no gravity).
/// \param[in] param Parameters for the solver.
TransportSolverTwophaseAd::TransportSolverTwophaseAd(const UnstructuredGrid& grid,
const IncompPropertiesInterface& props,
const LinearSolverInterface& linsolver,
const double* gravity,
const parameter::ParameterGroup& param)
: grid_(grid),
props_(props),
linsolver_(linsolver),
ops_(grid),
gravity_(0.0),
tol_(param.getDefault("nl_tolerance", 1e-9)),
maxit_(param.getDefault("nl_maxiter", 30))
{
const int nc = grid_.number_of_cells;
allcells_.resize(nc);
for (int i = 0; i < nc; ++i) {
allcells_[i] = i;
}
if (gravity && gravity[grid_.dimensions - 1] != 0.0) {
gravity_ = gravity[grid_.dimensions - 1];
for (int dd = 0; dd < grid_.dimensions - 1; ++dd) {
if (gravity[dd] != 0.0) {
THROW("TransportSolverTwophaseAd: can only handle gravity aligned with last dimension");
}
}
V htrans(grid.cell_facepos[grid.number_of_cells]);
tpfa_htrans_compute(const_cast<UnstructuredGrid*>(&grid), props.permeability(), htrans.data());
V trans(grid_.number_of_faces);
tpfa_trans_compute(const_cast<UnstructuredGrid*>(&grid), htrans.data(), trans.data());
const int num_internal = ops_.internal_faces.size();
transi_.resize(num_internal);
for (int fi = 0; fi < num_internal; ++fi) {
transi_[fi] = trans[ops_.internal_faces[fi]];
}
}
}
// Virtual destructor.
TransportSolverTwophaseAd::~TransportSolverTwophaseAd()
{
}
namespace
{
template <class ADB>
std::vector<ADB>
phaseMobility(const Opm::IncompPropertiesInterface& props,
const std::vector<int>& cells,
const typename ADB::V& sw)
{
typedef Eigen::Array<double, Eigen::Dynamic, 2, Eigen::RowMajor> TwoCol;
typedef Eigen::Array<double, Eigen::Dynamic, 4, Eigen::RowMajor> FourCol;
typedef typename ADB::V V;
typedef typename ADB::M M;
const int nc = props.numCells();
TwoCol s(nc, 2);
s.leftCols<1>() = sw;
s.rightCols<1>() = 1.0 - s.leftCols<1>();
TwoCol kr(nc, 2);
FourCol dkr(nc, 4);
props.relperm(nc, s.data(), cells.data(), kr.data(), dkr.data());
V krw = kr.leftCols<1>();
V kro = kr.rightCols<1>();
// In dkr, columns col(0..3) are:
// dkrw/dsw dkro/dsw dkrw/dso dkrw/dso <-- partial derivatives, really.
// If we want the derivatives with respect to some variable x,
// we must apply the chain rule:
// dkrw/dx = dkrw/dsw*dsw/dx + dkrw/dso*dso/dx.
// If x is sw as in our case we are left with.
// dkrw/dsw = col(0) - col(2)
// dkro/dsw = col(1) - col(3)
V dkrw = dkr.leftCols<1>() - dkr.rightCols<2>().leftCols<1>();
V dkro = dkr.leftCols<2>().rightCols<1>() - dkr.rightCols<1>();
M krwjac(nc,nc);
M krojac(nc,nc);
auto sizes = Eigen::ArrayXi::Ones(nc);
krwjac.reserve(sizes);
krojac.reserve(sizes);
for (int c = 0; c < nc; ++c) {
krwjac.insert(c,c) = dkrw(c);
krojac.insert(c,c) = dkro(c);
}
const double* mu = props.viscosity();
std::vector<M> dmw = { krwjac/mu[0] };
std::vector<M> dmo = { krojac/mu[1] };
std::vector<ADB> pmobc = { ADB::function(krw / mu[0], dmw) ,
ADB::function(kro / mu[1], dmo) };
return pmobc;
}
/// Returns fw(sw).
template <class ADB>
ADB
fluxFunc(const std::vector<ADB>& m)
{
assert (m.size() == 2);
ADB f = m[0] / (m[0] + m[1]);
return f;
}
} // anonymous namespace
/// Solve for saturation at next timestep.
/// Note that this only performs advection by total velocity, and
/// no gravity segregation.
/// \param[in] porevolume Array of pore volumes.
/// \param[in] source Transport source term. For interpretation see Opm::computeTransportSource().
/// \param[in] dt Time step.
/// \param[in, out] state Reservoir state. Calling solve() will read state.faceflux() and
/// read and write state.saturation().
void TransportSolverTwophaseAd::solve(const double* porevolume,
const double* source,
const double dt,
TwophaseState& state)
{
typedef Eigen::Array<double, Eigen::Dynamic, 2, Eigen::RowMajor> TwoCol;
typedef Eigen::Map<const V> Vec;
const int nc = grid_.number_of_cells;
const TwoCol s0 = Eigen::Map<const TwoCol>(state.saturation().data(), nc, 2);
double res_norm = 1e100;
const V sw0 = s0.leftCols<1>();
// sw1 is the object that will be changed every Newton iteration.
// V sw1 = sw0;
V sw1 = 0.5*V::Ones(nc,1);
const V dflux_all = Vec(state.faceflux().data(), grid_.number_of_faces, 1);
const int num_internal = ops_.internal_faces.size();
V dflux(num_internal);
for (int fi = 0; fi < num_internal; ++fi) {
dflux[fi] = dflux_all[ops_.internal_faces[fi]];
}
// Upwind selection of mobilities by phase.
// We have that for a phase P
// v_P = lambda_P K (-grad p + rho_P g grad z)
// and we assume that this has the same direction as
// v_P' = -grad p + rho_P g grad z.
// This may not be true for arbitrary anisotropic situations,
// but for scalar lambda and using TPFA it holds.
const V p1 = Vec(state.pressure().data(), nc, 1);
const V ndp = (ops_.ngrad * p1.matrix()).array();
typedef Eigen::Array<double, Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor> DynArr;
const V z = Eigen::Map<DynArr>(grid_.cell_centroids, nc, grid_.dimensions).rightCols<1>();
const V ndz = (ops_.ngrad * z.matrix()).array();
ASSERT(num_internal == ndp.size());
const double* density = props_.density();
const V vw = ndp - ndz*(gravity_*density[0]);
const V vo = ndp - ndz*(gravity_*density[1]);
const UpwindSelector<double> upwind_w(grid_, ops_, vw);
const UpwindSelector<double> upwind_o(grid_, ops_, vo);
// Compute more explicit and constant terms used in the equations.
const V pv = Vec(porevolume, nc, 1);
const V dtpv = dt/pv;
const V q = Vec(source, nc, 1);
const V qneg = q.min(V::Zero(nc,1));
const V qpos = q.max(V::Zero(nc,1));
const double gfactor = gravity_*(density[0] - density[1]);
const V gravflux = (gravity_ == 0.0) ? V(V::Zero(num_internal, 1))
: ndz*transi_*gfactor;
// Block pattern for variables.
// Primary variables:
// sw : one per cell
std::vector<int> bpat = { nc };
// Newton-Raphson loop.
int it = 0;
do {
// Assemble linear system.
const ADB sw = ADB::variable(0, sw1, bpat);
const std::vector<ADB> pmobc = phaseMobility<ADB>(props_, allcells_, sw.value());
const ADB fw_cell = fluxFunc(pmobc);
const std::vector<ADB> pmobf = { upwind_w.select(pmobc[0]),
upwind_o.select(pmobc[1]) };
const ADB fw_face = fluxFunc(pmobf);
const ADB flux = fw_face * (dflux - pmobf[1]*gravflux);
// const ADB fw_face = upwind_w.select(fw_cell);
// const ADB flux = fw_face * dflux;
const ADB qtr_ad = qpos + fw_cell*qneg;
const ADB transport_residual = sw - sw0 + dtpv*(ops_.div*flux - qtr_ad);
res_norm = transport_residual.value().matrix().norm();
std::cout << "Residual l2-norm = " << res_norm << std::endl;
// Solve linear system.
Eigen::SparseMatrix<double, Eigen::RowMajor> smatr = transport_residual.derivative()[0];
ASSERT(smatr.isCompressed());
V ds(nc);
LinearSolverInterface::LinearSolverReport rep
= linsolver_.solve(nc, smatr.nonZeros(),
smatr.outerIndexPtr(), smatr.innerIndexPtr(), smatr.valuePtr(),
transport_residual.value().data(), ds.data());
if (!rep.converged) {
THROW("Linear solver convergence error in TransportSolverTwophaseAd::solve()");
}
// Update (possible clamp) sw1.
sw1 = sw.value() - ds;
sw1 = sw1.min(V::Ones(nc,1)).max(V::Zero(nc,1));
it += 1;
} while (res_norm > tol_ && it < maxit_);
// Write to output data structure.
Eigen::Map<TwoCol> sref(state.saturation().data(), nc, 2);
sref.leftCols<1>() = sw1;
sref.rightCols<1>() = 1.0 - sw1;
}
} // namespace Opm