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SchnakenbergD2Q5v.cpp
1 /* Copyright (c) 2013 David Sichau <mail"at"sichau"dot"eu>
2  * 2013-2015 Simon Tanaka <tanakas"at"gmx"dot"ch>
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22 #include <LbmLib/include/nodes/BoundaryNode.hpp>
23 #include <LbmLib/include/nodes/PhysicalNode.hpp>
24 #include <LbmLib/include/GlobalSimulationParameters.hpp>
25 #include <LbmLib/include/solver/BoundaryAbstractSolver.hpp>
26 #include <LbmLib/include/solver/CDESolver/SchnakenbergD2Q5v.hpp>
27 
28 #include <UtilLib/include/Exception.hpp>
29 #include <UtilLib/include/Log.hpp>
30 #include <algorithm>
31 #include <cassert>
32 #include <numeric>
33 #include <string>
34 #include <random>
35 namespace LbmLib {
36 namespace solver {
37 namespace {
38 const double gamma = 800.0;
39 const double b = 0.9;
40 double deltaT;
41 }
42 
43 
45  // init with C = 1 + eps where eps is a random number with mean 0 and std 0.01
46  static std::random_device rd;
47  static std::mt19937 gen(rd());
48  static std::uniform_real_distribution<> dis(-0.01, 0.01);
49  double temp = 0.2 * (1.0 + dis(gen));
50  for (auto d : cdeDirIter_) {
51  distributions_[d] = temp;
52  }
53  deltaT = 20.0 / Parameters.getIterations();
54 }
55 
56 void SchnakenbergD2Q5v::writeSolver(std::ostream* const stream) {
57  (*stream) << physicalNode_->getXPos() << '\t' << physicalNode_->getYPos();
58  for (auto d : distributions_) {
59  (*stream) << '\t' << d;
60  }
61  (*stream) << '\n';
62 }
63 
64 void SchnakenbergD2Q5v::loadSolver(std::stringstream* const stream) {
65  int x, y;
66  (*stream) >> x >> y;
67  assert(physicalNode_->getXPos() == x && "The position does not match");
68  assert(physicalNode_->getYPos() == y && "The position does not match");
69  for (auto d : cdeDirIter_) {
70  (*stream) >> distributions_[d];
71  }
72 }
73 
74 double& SchnakenbergD2Q5v::accessDistribution(const Direction& dir) {
75  assert(dir > T && dir < NE);
76  return distributions_[dir];
77 }
78 
79 void SchnakenbergD2Q5v::rescaleDistributions(const double factor) {
80  for (auto &it: this->distributions_) {
81  it *= factor;
82  }
83 }
84 
85 double SchnakenbergD2Q5v::getC() const {
86  return std::accumulate(distributions_.begin(), distributions_.end(), 0.0);
87 }
88 
90  assert(physicalNode_ != nullptr);
91  // Calculate the rho
92  const double C = getC();
93 
94  // calculate the speeds
95  const double ux = physicalNode_->getFluidSolver().getVelocity().x;
96  const double uy = physicalNode_->getFluidSolver().getVelocity().y;
97 
98  const double w0 = C / 3.0;
99  const double w1 = C / 6.0;
100  const double tauI = 1.0 / getTau();
101 
102 
103  double temp[5];
104  temp[T] = w0;
105  temp[E] = w1 * (1.0 + ux * 3.0);
106  temp[N] = w1 * (1.0 + uy * 3.0);
107  temp[W] = w1 * (1.0 + (-ux) * 3.0);
108  temp[S] = w1 * (1.0 + (-uy) * 3.0);
109 
110  const double Cu =
111  physicalNode_->getCDESolverSlow("SchnakenbergD2Q5u").getC();
112  double reaktionTerm = deltaT * gamma * (b - Cu * Cu * C) / 3.0;
113  double reaktionTermR = deltaT * gamma * (b - Cu * Cu * C) / 6.0;
114  if (this->physicalNode_->getDomainIdentifier() == 0) {
115  reaktionTerm = 0.0;
116  reaktionTermR = 0.0;
117  }
118  distributions_[T] = distributions_[T] - distributions_[T] * tauI + temp[T] *
119  tauI + reaktionTerm;
120  distributions_[E] = distributions_[E] - distributions_[E] * tauI + temp[E] *
121  tauI + reaktionTermR;
122  distributions_[N] = distributions_[N] - distributions_[N] * tauI + temp[N] *
123  tauI + reaktionTermR;
124  distributions_[W] = distributions_[W] - distributions_[W] * tauI + temp[W] *
125  tauI + reaktionTermR;
126  distributions_[S] = distributions_[S] - distributions_[S] * tauI + temp[S] *
127  tauI + reaktionTermR;
128  // for (auto d : cdeDirIter_) {
129  // double tempD = distributions_[d];
130  // // compute non equilibirum
131  // // make relaxation
132  // distributions_[d] = tempD - tempD * tauI + temp[d] * tauI +
133  // reaktionTerm;
134  // }
135 
136 
137  // preparation for advect step
138  localSwap();
139 }
140 
141 double SchnakenbergD2Q5v::calculateEquilibrium(const Direction& dir) {
142  const double C = getC();
143  // calculate the speeds
144  const double u = physicalNode_->getFluidSolver().getVelocity().x;
145  const double v = physicalNode_->getFluidSolver().getVelocity().y;
146 
147  const double w1 = C / 6.0;
148 
149  switch (dir) {
150  case T:
151  return C / 3.0;
152  break;
153  case E:
154  return w1 * (1.0 + u * 3.0);
155  break;
156  case N:
157  return w1 * (1.0 + v * 3.0);
158  break;
159  case W:
160  return w1 * (1.0 + (-u) * 3.0);
161  break;
162  case S:
163  return w1 * (1.0 + (-v) * 3.0);
164  break;
165  default:
166  assert(
167  false &&
168  "you want to get a inverse direction of a Direction that does not exist");
169  }
170  return 0;
171 }
172 
174  assert(physicalNode_ != nullptr);
175  std::swap(distributions_[getInverseDirection(W)],
178  std::swap(distributions_[getInverseDirection(S)],
181 }
182 
183 void SchnakenbergD2Q5v::localSwap() {
184  std::swap(distributions_[E], distributions_[W]);
185  std::swap(distributions_[N], distributions_[S]);
186 }
187 
189  double sumC = 0.0;
190  int counter = 0;
191  for (auto d : cdeDirIter_) {
192  // if it has no boundary neighbour and the neighbour is in the same domain then get the concentration
193  if ((d != T) &&
194  (this->physicalNode_->getBoundaryNeighbour(d) == nullptr) &&
197  getDomainIdentifier()) ) {
199  solverID_).getC();
200  counter++;
201  }
202  }
203  if (counter == 0) {
204  std::array<Direction, 4> dir {{NE, NW, SW, SE}
205  };
206  for (auto d : dir) {
207  // we need to check the diagonals as it does not work in the other directions
208  if (this->physicalNode_->getDomainIdentifier() ==
210  getDomainIdentifier()) {
211  sumC +=
213  solverID_).getC();
214  counter++;
215  }
216  }
217  LOG(UtilLib::logINFO) <<
218  "the default initialisation failed. Therefore the node was reinitialised from the diagonal directions";
219  }
220  if (counter == 0) {
222  "The cde solver failed to reinitialise the node, this might be due to a stange geometry");
223  }
224  sumC /= static_cast<double>(counter);
225  for (auto d : cdeDirIter_) {
226  distributions_[d] = sumC * 0.25;
227  }
228  this->collide();
229 }
230 
231 const std::string SchnakenbergD2Q5v::name = "SchnakenbergD2Q5v";
232 
233 
234 CDEDirectionsIteratorD2Q5 const SchnakenbergD2Q5v::cdeDirIter_ =
236 
237 SchnakenbergD2Q5v::SchnakenbergD2Q5v() : BaseCDESolver(),
238  distributions_(std::array<double,
239  5> {
240  {0.0, 0.0, 0.0,
241  0.0, 0.0}
242  }
243 
244  )
245 {}
246 }
247 } // end namespace
solver::CDEAbstractSolver & getCDESolverSlow(const std::string &name) const
getCDESolverSlow Getter method for the cde Solver
The Base class for all CDESolver implementations This classes uses the recursive template idiom to au...
size_t solverID_
solverID_ The ID of the solver instance. Coincides with the index in the vector PhysicalNode::cdeSolv...
PhysicalNode * getPhysicalNeighbour(const Direction &d) const
getPhysicalNeighbour Getter method to access the Physical Neighbour
const nodes::PhysicalNode * physicalNode_
physicalNode_ The physical Node which owns this solver
The CDEDirectionsIteratorD2Q5 class Provides methods to handle the Directions. Use the Function Direc...
Definition: Direction.hpp:126
T x
x the value in x direction
Definition: Field.hpp:50
virtual double & accessDistribution(const Direction &dir)=0
accessDistribution Access to the distribution
virtual void advect()
advect The advect step of the LBM
unsigned int getDomainIdentifier() const
getter for the Domain Identifier of this node
virtual double getC() const =0
getC Calculates the concentration on this node
virtual void initSolver()
initSolver Use this to initalise the solver
virtual double calculateEquilibrium(const Direction &dir)
calculateEquilibrium calculates the equilibirum for direction dir
virtual void writeSolver(std::ostream *const stream)
writes the solver to the stream
virtual void collide()
collide The collision step of the LBM
const Field< double > & getVelocity() const
getVelocity Returns the current velocity of the fluid
double getTau() const
getTau Getter method for the tau parameter
const solver::FluidSolver & getFluidSolver() const
getFluidSolver Const getter method for the fluid Solver
virtual void loadSolver(std::stringstream *const stream)
loads the solver from the stream
int getXPos() const
getXPos Getter for the X position
virtual double & accessDistribution(const Direction &dir)
accessDistribution Access to the distribution
BoundaryNode * getBoundaryNeighbour(const Direction &d) const
getBoundaryNeighbour Getter method to access the Boundary Neighbour
int getYPos() const
getYPos Getter for the Y position
solver::CDEAbstractSolver & getCDESolver(size_t id) const
getCDESolver Getter method for the cde Solver
virtual void rescaleDistributions(const double factor)
Rescales all distributions by a factor.
virtual double getC() const
getC Calculates the concentration on this node
virtual void reinitialise()
reinitialise this solver as the corresponding physical node has switched domain
T y
y the value in y direction
Definition: Field.hpp:54