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 <
utilities/aslParametersManager.h
>
#include <
math/aslTemplates.h
>
#include <
aslGeomInc.h
>
#include <
math/aslPositionFunction.h
>
#include <
aslDataInc.h
>
#include <
acl/aclGenerators.h
>
#include <
writers/aslVTKFormatWriters.h
>
#include <
num/aslLBGK.h
>
#include <
num/aslLBGKBC.h
>
#include <
utilities/aslTimer.h
>
#include <
readers/aslVTKFormatReaders.h
>
// typedef to switch to double precision
//typedef double FlT;
typedef
float
FlT
;
using
asl::AVec
;
using
asl::makeAVec
;
// Generate geometry of the tunnel
asl::SPDistanceFunction
generateTunnel
(
asl::Block
& bl)
{
// 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::SPLBGK
lbgk(
new
asl::LBGKTurbulence
(block,
acl::generateVEConstant
(
FlT
(nu.v())),
&
asl::d3q15
()));
lbgk->init();
// Generate an instance for LBGK data initialization
asl::SPLBGKUtilities
lbgkUtil(
new
asl::LBGKUtilities
(lbgk));
// 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.),
{
asl::X0
,
asl::XE
}));
// 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
(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
executeAll
(bc);
// 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;
}
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