ASL  0.1.7
Advanced Simulation Library
locomotive.cc

Example: Aerodynamics of a locomotive in a tunnel Required input file: locomotive.stl

/*
* Advanced Simulation Library <http://asl.org.il>
*
* Copyright 2015 Avtech Scientific <http://avtechscientific.com>
*
*
* This file is part of Advanced Simulation Library (ASL).
*
* ASL is free software: you can redistribute it and/or modify it
* under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, version 3 of the License.
*
* ASL 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with ASL. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <aslGeomInc.h>
#include <aslDataInc.h>
#include <num/aslLBGK.h>
#include <num/aslLBGKBC.h>
// typedef to switch to double precision
//typedef double FlT;
typedef float FlT;
using asl::AVec;
// Generate geometry of the tunnel
{
// Set length of the tunnel to the length (X size) of the block
double l(bl.getBPosition()[0] - bl.position[0] + bl.dx);
// Set radius of the tunnel to the ca. half of the block's height (Z size)
double rTunnel((bl.getBPosition()[2] - bl.position[2]) / 2.1);
// Center of the tunnel (described as cylinder cut by a plane)
asl::AVec<> center(.5 * (bl.getBPosition() + bl.position));
center[1] = bl.position[1] + .25 * rTunnel;
// Center of the ground plane (that cuts the cylinder)
asl::AVec<> centerG(center);
centerG[1] = bl.position[1];
/* DF = DistanceFunction (part of the geometrical module of ASL)
1. Genarate cylinder
2. Generate ground plane
3. Conjunction of the cylinder and the plane ('&' - operator)
4. Space inversion ('-' - operator) */
auto tunnel(-(generateDFCylinder(rTunnel, makeAVec(l, 0., 0.), center) &
generateDFPlane(makeAVec(0., -1., 0.), centerG)));
// Normalize DistanceFunction to the range [-1; 1]
return normalize(tunnel, bl.dx);
}
int main(int argc, char* argv[])
{
/* Convenience facility to manage simulation parameters (and also
hardware parameters defining platform and device for computations)
through command line and/or parameters file.
See `locomotive --help` for more information */
asl::ApplicationParametersManager appParamsManager("locomotive",
"1.0");
/* Important: declare Parameters only after declaring
ApplicationParametersManager instance because each Parameter adds itself
to it automatically!
0.08 - default value; will be used if nothing else is provided during
runtime through command line or parameters file.
"dx" - option key; is used to specify this parameter through command line
and/or parameters file, like `locomotive --dx 0.05`
"space step" - option description; is used in the help output:
`locomotive -h` and as comment on parameters file generation:
`locomotive -g ./defaultParameters.ini`
"m" - parameter units; is used to complement the option description mentioned
above. Might be used for automatic unit conversion in future (to this end
it is recommended to use the notation of the Boost::Units library). */
asl::Parameter<FlT> dx(0.08, "dx", "space step", "m");
asl::Parameter<FlT> dt(1., "dt", "time step", "s");
asl::Parameter<FlT> nu(.001, "nu", "kinematic viscosity", "m^2/s");
asl::Parameter<unsigned int> iterations(10001, "iterations", "iterations number");
asl::Parameter<string> input("input", "path to the geometry input file");
/* Load previously declared Parameters from command line and/or
parameters file. Use default values if neither is provided. */
appParamsManager.load(argc, argv);
/* Set the size of the block to 40x10x15 m (in accordance with the
locomotive size read later on from the input file) */
AVec<int> size(makeAVec(40., 10., 15.) * (1. / dx.v()));
/* Create block and shift it in accordance with the
position of the locomotive in the input file */
asl::Block bl(size, dx.v(), makeAVec(-30., 8.58, 1.53));
// Define dimensionless viscosity value
FlT nuNum(nu.v() * dt.v() / dx.v() / dx.v());
cout << "Data initialization... " << flush;
// Read geometry of the locomotive from the file `locomotive.stl`
auto locomotive(asl::readSurface(input.v(), bl));
// Create block for further use
asl::Block block(locomotive->getInternalBlock());
// Generate memory data container for the tunnel
auto tunnelMap(asl::generateDataContainerACL_SP<FlT>(block, 1, 1u));
// Place generated geometry of the tunnel into the tunnel data container
asl::initData(tunnelMap, generateTunnel(block));
// Data container for air friction field
auto forceField(asl::generateDataContainerACL_SP<FlT>(block, 3, 1u));
// Initialization
asl::initData(forceField, makeAVec(0., 0., 0.));
cout << "Finished" << endl;
cout << "Numerics initialization... " << flush;
// NOTE: the problem is considered in the reference frame related to the locomotive
// Generate numerical method for air flow - LBGK (lattice Bhatnagar–Gross–Krook)
&asl::d3q15()));
lbgk->init();
// Generate an instance for LBGK data initialization
// Initialize the LBGK internal data with the flow velocity of (0.1, 0, 0) in [lattice units]
lbgkUtil->initF(acl::generateVEConstant(.1, .0, .0));
auto vfTunnel(asl::generatePFConstant(makeAVec(0.1, 0., 0.)));
std::vector<asl::SPNumMethod> bc;
std::vector<asl::SPNumMethod> bcV;
// Generate boundary conditions for the tunnel geometry. Constant velocity BC
bc.push_back(generateBCVelocity(lbgk, vfTunnel, tunnelMap));
// Generate boundary conditions for the tunnel geometry. Constant velocity BC
// This BC is used for visualization.
bcV.push_back(generateBCVelocityVel(lbgk, vfTunnel, tunnelMap));
bcV.push_back(generateBCNoSlipRho(lbgk, tunnelMap));
// Generate boundary conditions for the locomotive geometry. Non-slip BC
bc.push_back(generateBCNoSlip(lbgk, locomotive));
bcV.push_back(generateBCNoSlipVel(lbgk, locomotive));
bcV.push_back(generateBCNoSlipRho(lbgk, locomotive));
// Generate constant presure BC for in and out planes of the tunnel
bc.push_back(generateBCConstantPressureVelocity(lbgk, 1.,
makeAVec(0.1, 0., 0.),
// Initialization and building of all BC
initAll(bc);
initAll(bcV);
// Generate a numerical method for computation of the air force field that acts on the locomotive
auto computeForce(generateComputeSurfaceForce(lbgk, forceField, locomotive));
computeForce->init();
cout << "Finished" << endl;
cout << "Computing..." << endl;
asl::Timer timer;
// Initialization of the output system
// Write the output to the directory containing the input parameters file (default "./")
asl::WriterVTKXML writer(appParamsManager.getDir() + "locomotive");
writer.addScalars("map", *locomotive);
writer.addScalars("tunnel", *tunnelMap);
writer.addScalars("rho", *lbgk->getRho());
writer.addVector("v", *lbgk->getVelocity());
writer.addVector("force", *forceField);
// Execute all BC
executeAll(bcV);
computeForce->execute();
// First data output
writer.write();
timer.start();
// Iteration loop
for (unsigned int i(1); i < iterations.v(); ++i)
{
// One iteration (timestep) of bulk numerical procedure
lbgk->execute();
// Execution of the BC procedures
// Output and analysis scope
if (!(i%1000))
{
cout << i << endl;
// Execution of the visualization BC procedures
executeAll(bcV);
// Computation of the force field
computeForce->execute();
// Data writing
writer.write();
}
}
timer.stop();
cout << "Finished" << endl;
cout << "Computation statistic:" << endl;
cout << "Real Time = " << timer.realTime() << "; Processor Time = "
<< timer.processorTime() << "; Processor Load = "
<< timer.processorLoad() * 100 << "%" << endl;
return 0;
}