summaryrefslogtreecommitdiff
path: root/examples/laminar/cylinder2d/cylinder2d.cpp
blob: b7879cb20863d91e4944cea2fe559239e8973e12 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
/*  Lattice Boltzmann sample, written in C++, using the OpenLB
 *  library
 *
 *  Copyright (C) 2006-2014 Jonas Latt, Mathias J. Krause,
 *  Vojtech Cvrcek, Peter Weisbrod
 *  E-mail contact: info@openlb.net
 *  The most recent release of OpenLB can be downloaded at
 *  <http://www.openlb.net/>
 *
 *  This program 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 2
 *  of the License, or (at your option) any later version.
 *
 *  This program 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 this program; if not, write to the Free
 *  Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA  02110-1301, USA.
 */

/* cylinder2d.cpp:
 * This example examines a steady flow past a cylinder placed in a channel.
 * The cylinder is offset somewhat from the center of the flow to make the
 * steady-state symmetrical flow unstable. At the inlet, a Poiseuille profile is
 * imposed on the velocity, whereas the outlet implements a Dirichlet pressure
 * condition set by p = 0.
 * Inspired by "Benchmark Computations of Laminar Flow Around
 * a Cylinder" by M.Schäfer and S.Turek. For high resolution, low
 * latticeU, and enough time to converge, the results for pressure drop, drag
 * and lift lie within the estimated intervals for the exact results.
 * An unsteady flow with Karman vortex street can be created by changing the
 * Reynolds number to Re=100.
 */


#include "olb2D.h"
#ifndef OLB_PRECOMPILED // Unless precompiled version is used,
#include "olb2D.hh"   // include full template code
#endif
#include <vector>
#include <cmath>
#include <iostream>
#include <fstream>

using namespace olb;
using namespace olb::descriptors;
using namespace olb::graphics;
using namespace olb::util;
using namespace std;

typedef double T;
#define DESCRIPTOR D2Q9<>


// Parameters for the simulation setup
const int N = 10;       // resolution of the model
const T Re = 20.;       // Reynolds number
const T maxPhysT = 16.; // max. simulation time in s, SI unit
const T L = 0.1/N;      // latticeL
const T lengthX = 2.2;
const T lengthY = .41+L;
const T centerCylinderX = 0.2;
const T centerCylinderY = 0.2+L/2.;
const T radiusCylinder = 0.05;


// Stores geometry information in form of material numbers
void prepareGeometry( UnitConverter<T, DESCRIPTOR> const& converter,
                      SuperGeometry2D<T>& superGeometry )
{

  OstreamManager clout( std::cout,"prepareGeometry" );
  clout << "Prepare Geometry ..." << std::endl;

  Vector<T,2> extend( lengthX,lengthY );
  Vector<T,2> center( centerCylinderX,centerCylinderY );
  Vector<T,2> origin;
  IndicatorCircle2D<T> circle( center, radiusCylinder );

  superGeometry.rename( 0,2 );

  superGeometry.rename( 2,1,1,1 );

  // Set material number for inflow
  extend[0] = 2.*L;
  origin[0] = -L;
  IndicatorCuboid2D<T> inflow( extend, origin );
  superGeometry.rename( 2,3,1,inflow );
  // Set material number for outflow
  origin[0] = lengthX-L;
  IndicatorCuboid2D<T> outflow( extend, origin );
  superGeometry.rename( 2,4,1,outflow );
  // Set material number for cylinder
  superGeometry.rename( 1,5,circle );

  // Removes all not needed boundary voxels outside the surface
  superGeometry.clean();
  superGeometry.checkForErrors();

  superGeometry.print();

  clout << "Prepare Geometry ... OK" << std::endl;
}

// Set up the geometry of the simulation
void prepareLattice( SuperLattice2D<T,DESCRIPTOR>& sLattice,
                     UnitConverter<T, DESCRIPTOR> const& converter,
                     Dynamics<T, DESCRIPTOR>& bulkDynamics,
                     sOnLatticeBoundaryCondition2D<T,DESCRIPTOR>& sBoundaryCondition,
                     sOffLatticeBoundaryCondition2D<T,DESCRIPTOR>& offBc,
                     SuperGeometry2D<T>& superGeometry )
{

  OstreamManager clout( std::cout,"prepareLattice" );
  clout << "Prepare Lattice ..." << std::endl;

  const T omega = converter.getLatticeRelaxationFrequency();

  // Material=0 -->do nothing
  sLattice.defineDynamics( superGeometry, 0, &instances::getNoDynamics<T, DESCRIPTOR>() );

  // Material=1 -->bulk dynamics
  // Material=3 -->bulk dynamics (inflow)
  // Material=4 -->bulk dynamics (outflow)
  auto bulkIndicator = superGeometry.getMaterialIndicator({1, 3, 4});
  sLattice.defineDynamics( bulkIndicator, &bulkDynamics );

  // Material=2 -->bounce back
  sLattice.defineDynamics( superGeometry, 2, &instances::getBounceBack<T, DESCRIPTOR>() );

  // Setting of the boundary conditions
  sBoundaryCondition.addVelocityBoundary( superGeometry, 3, omega );
  sBoundaryCondition.addPressureBoundary( superGeometry, 4, omega );

  // Material=5 -->bounce back
  //sLattice.defineDynamics(superGeometry, 5, &instances::getBounceBack<T, DESCRIPTOR>());

  // Material=5 -->bouzidi

  Vector<T,2> center( centerCylinderX,centerCylinderY );
  IndicatorCircle2D<T> circle( center, radiusCylinder );

  sLattice.defineDynamics( superGeometry, 5, &instances::getNoDynamics<T,DESCRIPTOR>() );
  offBc.addZeroVelocityBoundary( superGeometry, 5, circle );

  // Initial conditions
  AnalyticalConst2D<T,T> rhoF( 1 );
  std::vector<T> velocity( 2,T( 0 ) );
  AnalyticalConst2D<T,T> uF( velocity );

  // Initialize all values of distribution functions to their local equilibrium
  sLattice.defineRhoU( bulkIndicator, rhoF, uF );
  sLattice.iniEquilibrium( bulkIndicator, rhoF, uF );

  // Make the lattice ready for simulation
  sLattice.initialize();

  clout << "Prepare Lattice ... OK" << std::endl;
}

// Generates a slowly increasing inflow for the first iTMaxStart timesteps
void setBoundaryValues( SuperLattice2D<T, DESCRIPTOR>& sLattice,
                        UnitConverter<T, DESCRIPTOR> const& converter, int iT,
                        SuperGeometry2D<T>& superGeometry )
{

  OstreamManager clout( std::cout,"setBoundaryValues" );

  // No of time steps for smooth start-up
  int iTmaxStart = converter.getLatticeTime( maxPhysT*0.4 );
  int iTupdate = 5;

  if ( iT%iTupdate==0 && iT<= iTmaxStart ) {
    // Smooth start curve, sinus
    // SinusStartScale<T,int> StartScale(iTmaxStart, T(1));

    // Smooth start curve, polynomial
    PolynomialStartScale<T,T> StartScale( iTmaxStart, T( 1 ) );

    // Creates and sets the Poiseuille inflow profile using functors
    T iTvec[1] = {T( iT )};
    T frac[1] = {};
    StartScale( frac,iTvec );
    T maxVelocity = converter.getCharLatticeVelocity()*3./2.*frac[0];
    T distance2Wall = L/2.;
    Poiseuille2D<T> poiseuilleU( superGeometry, 3, maxVelocity, distance2Wall );

    sLattice.defineU( superGeometry, 3, poiseuilleU );
  }

}

// Computes the pressure drop between the voxels before and after the cylinder
void getResults( SuperLattice2D<T, DESCRIPTOR>& sLattice,
                 UnitConverter<T, DESCRIPTOR> const& converter, int iT,
                 SuperGeometry2D<T>& superGeometry, Timer<T>& timer,
                 CircularBuffer<T>& buffer )
{

  OstreamManager clout( std::cout,"getResults" );

  SuperVTMwriter2D<T> vtmWriter( "cylinder2d" );
  SuperLatticePhysVelocity2D<T, DESCRIPTOR> velocity( sLattice, converter );
  SuperLatticePhysPressure2D<T, DESCRIPTOR> pressure( sLattice, converter );
  vtmWriter.addFunctor( velocity );
  vtmWriter.addFunctor( pressure );

  const int vtkIter  = converter.getLatticeTime( .3 );
  const int statIter = converter.getLatticeTime( .1 );

  T point[2] = {};
  point[0] = centerCylinderX + 3*radiusCylinder;
  point[1] = centerCylinderY;
  AnalyticalFfromSuperF2D<T> intpolateP( pressure, true );
  T p;
  intpolateP( &p,point );
  buffer.insert(p);

  if ( iT == 0 ) {
    // Writes the geometry, cuboid no. and rank no. as vti file for visualization
    SuperLatticeGeometry2D<T, DESCRIPTOR> geometry( sLattice, superGeometry );
    SuperLatticeCuboid2D<T, DESCRIPTOR> cuboid( sLattice );
    SuperLatticeRank2D<T, DESCRIPTOR> rank( sLattice );
    vtmWriter.write( geometry );
    vtmWriter.write( cuboid );
    vtmWriter.write( rank );

    vtmWriter.createMasterFile();
  }

  // Writes the vtk files
  if ( iT%vtkIter == 0 && iT > 0 ) {
    vtmWriter.write( iT );

    SuperEuklidNorm2D<T, DESCRIPTOR> normVel( velocity );
    BlockReduction2D2D<T> planeReduction( normVel, 600, BlockDataSyncMode::ReduceOnly );
    // write output as JPEG
    heatmap::write(planeReduction, iT);
  }

  // Gnuplot constructor (must be static!)
  // for real-time plotting: gplot("name", true) // experimental!
  static Gnuplot<T> gplot( "drag" );

  // write pdf at last time step
  if ( iT == converter.getLatticeTime( maxPhysT )-1 ) {
    // writes pdf
    gplot.writePDF();
  }

  // Writes output on the console
  if ( iT%statIter == 0 ) {
    // Timer console output
    timer.update( iT );
    timer.printStep();
    clout << "Circular buffer test: moving average pointwise value=" << buffer.average() << std::endl;

    // Lattice statistics console output
    sLattice.getStatistics().print( iT,converter.getPhysTime( iT ) );

    // Drag, lift, pressure drop
    AnalyticalFfromSuperF2D<T> intpolatePressure( pressure, true );
    SuperLatticePhysDrag2D<T,DESCRIPTOR> drag( sLattice, superGeometry, 5, converter );


    T point1[2] = {};
    T point2[2] = {};

    point1[0] = centerCylinderX - radiusCylinder;
    point1[1] = centerCylinderY;

    point2[0] = centerCylinderX + radiusCylinder;
    point2[1] = centerCylinderY;

    T p1, p2;
    intpolatePressure( &p1,point1 );
    intpolatePressure( &p2,point2 );

    clout << "pressure1=" << p1;
    clout << "; pressure2=" << p2;

    T pressureDrop = p1-p2;
    clout << "; pressureDrop=" << pressureDrop;

    int input[3] = {};
    T _drag[drag.getTargetDim()];
    drag( _drag,input );
    clout << "; drag=" << _drag[0] << "; lift=" << _drag[1] << endl;

    // set data for gnuplot: input={xValue, yValue(s), names (optional), position of key (optional)}
    gplot.setData( converter.getPhysTime( iT ), {_drag[0], 5.58}, {"drag(openLB)", "drag(schaeferTurek)"}, "bottom right", {'l','l'} );
    // writes a png in one file for every timestep, if the file is open it can be used as a "liveplot"
    gplot.writePNG();

    // every (iT%vtkIter) write an png of the plot
    if ( iT%( vtkIter ) == 0 ) {
      // writes pngs: input={name of the files (optional), x range for the plot (optional)}
      gplot.writePNG( iT, maxPhysT );
    }
  }
}

int main( int argc, char* argv[] )
{

  // === 1st Step: Initialization ===
  olbInit( &argc, &argv );
  singleton::directories().setOutputDir( "./tmp/" );
  OstreamManager clout( std::cout,"main" );
  // display messages from every single mpi process
  //clout.setMultiOutput(true);

  UnitConverterFromResolutionAndRelaxationTime<T, DESCRIPTOR> const converter(
    int {N},                        // resolution: number of voxels per charPhysL
    (T)   0.56,                     // latticeRelaxationTime: relaxation time, have to be greater than 0.5!
    (T)   2.0*radiusCylinder,       // charPhysLength: reference length of simulation geometry
    (T)   0.2,                      // charPhysVelocity: maximal/highest expected velocity during simulation in __m / s__
    (T)   0.2*2.*radiusCylinder/Re, // physViscosity: physical kinematic viscosity in __m^2 / s__
    (T)   1.0                       // physDensity: physical density in __kg / m^3__
  );
  // Prints the converter log as console output
  converter.print();
  // Writes the converter log in a file
  converter.write("cylinder2d");

  // === 2rd Step: Prepare Geometry ===
  Vector<T,2> extend( lengthX,lengthY );
  Vector<T,2> origin;
  IndicatorCuboid2D<T> cuboid( extend, origin );

  // Instantiation of a cuboidGeometry with weights
#ifdef PARALLEL_MODE_MPI
  const int noOfCuboids = singleton::mpi().getSize();
#else
  const int noOfCuboids = 7;
#endif
  CuboidGeometry2D<T> cuboidGeometry( cuboid, L, noOfCuboids );

  // Instantiation of a loadBalancer
  HeuristicLoadBalancer<T> loadBalancer( cuboidGeometry );

  // Instantiation of a superGeometry
  SuperGeometry2D<T> superGeometry( cuboidGeometry, loadBalancer, 2 );

  prepareGeometry( converter, superGeometry );

  // === 3rd Step: Prepare Lattice ===
  SuperLattice2D<T, DESCRIPTOR> sLattice( superGeometry );

  BGKdynamics<T, DESCRIPTOR> bulkDynamics( converter.getLatticeRelaxationFrequency(), instances::getBulkMomenta<T, DESCRIPTOR>() );

  // choose between local and non-local boundary condition
  sOnLatticeBoundaryCondition2D<T,DESCRIPTOR> sBoundaryCondition( sLattice );
  // createInterpBoundaryCondition2D<T,DESCRIPTOR>(sBoundaryCondition);
  createLocalBoundaryCondition2D<T,DESCRIPTOR>( sBoundaryCondition );

  sOffLatticeBoundaryCondition2D<T, DESCRIPTOR> sOffBoundaryCondition( sLattice );
  createBouzidiBoundaryCondition2D<T, DESCRIPTOR> ( sOffBoundaryCondition );

  prepareLattice( sLattice, converter, bulkDynamics, sBoundaryCondition, sOffBoundaryCondition, superGeometry );

  // === 4th Step: Main Loop with Timer ===
  CircularBuffer<T> buffer(converter.getLatticeTime(.2));
  clout << "starting simulation..." << endl;
  Timer<T> timer( converter.getLatticeTime( maxPhysT ), superGeometry.getStatistics().getNvoxel() );
  timer.start();

  for ( int iT = 0; iT < converter.getLatticeTime( maxPhysT ); ++iT ) {
    // === 5th Step: Definition of Initial and Boundary Conditions ===
    setBoundaryValues( sLattice, converter, iT, superGeometry );

    // === 6th Step: Collide and Stream Execution ===
    sLattice.collideAndStream();

    // === 7th Step: Computation and Output of the Results ===
    getResults( sLattice, converter, iT, superGeometry, timer, buffer );
  }

  timer.stop();
  timer.printSummary();
}