void testPointUnitSphere( const math::Vector3<real_t> & p )
{
static const geometry::Sphere UNIT_SPHERE( math::Vector3<real_t>( 0, 0, 0 ), real_t( 1 ) );
static const real_t EPSILON = real_t(1e-4);
real_t q = lbm::intersectionRatioBisection( UNIT_SPHERE, p, -p, EPSILON );
Vector3<real_t> intersectionPoint = p + (-p) * q;
real_t intersectionRadius = intersectionPoint.length();
WALBERLA_CHECK_LESS( std::fabs( intersectionRadius - real_t( 1 ) ), EPSILON );
q = lbm::intersectionRatioSphere( UNIT_SPHERE, p, -p );
intersectionPoint = p + ( -p ) * q;
intersectionRadius = intersectionPoint.length();
WALBERLA_CHECK_LESS( std::fabs( intersectionRadius - real_t( 1 ) ), EPSILON );
q = lbm::intersectionRatio( UNIT_SPHERE, p, -p, EPSILON );
intersectionPoint = p + ( -p ) * q;
intersectionRadius = intersectionPoint.length();
WALBERLA_CHECK_LESS( std::fabs( intersectionRadius - real_t( 1 ) ), EPSILON );
}
void testAABB()
{
static const math::Vector3<real_t> ZERO( real_t( 0 ), real_t( 0 ), real_t( 0 ) );
static const math::Vector3<real_t> UNIT( real_t( 1 ), real_t( 1 ), real_t( 1 ) );
static const real_t EPSILON = real_t(1e-4);
boost::random::mt19937 randomEngine;
std::vector<math::AABB> testAABBs;
testAABBs.push_back( math::AABB( -UNIT, UNIT ) );
testAABBs.push_back( math::AABB( ZERO, UNIT ) );
testAABBs.push_back( math::AABB( -UNIT, ZERO ) );
for( auto aabbIt = testAABBs.begin(); aabbIt != testAABBs.end(); ++aabbIt )
{
const math::AABB outerAABB = aabbIt->getScaled( real_t( 2 ) );
std::vector< std::pair< Vector3<real_t>, Vector3<real_t> > > testPoints;
for( int i = 0; i < 100; ++i )
{
Vector3<real_t> outerPoint, innerPoint;
do { outerPoint = outerAABB.randomPoint( randomEngine ); } while( aabbIt->contains( outerPoint ) );
innerPoint = aabbIt->randomPoint( randomEngine );
testPoints.push_back( std::make_pair( outerPoint, innerPoint - outerPoint ) );
}
for( auto pointIt = testPoints.begin(); pointIt != testPoints.end(); ++pointIt )
{
const Vector3<real_t> & fluidPoint = pointIt->first;
const Vector3<real_t> & direction = pointIt->second;
real_t q = lbm::intersectionRatio( *aabbIt, fluidPoint, direction, EPSILON );
Vector3<real_t> intersectionPoint = fluidPoint + direction * q;
WALBERLA_CHECK_LESS( std::fabs( aabbIt->sqSignedDistance( intersectionPoint ) ), EPSILON * EPSILON );
q = lbm::intersectionRatioBisection( *aabbIt, fluidPoint, direction, EPSILON );
intersectionPoint = fluidPoint + direction * q;
WALBERLA_CHECK_LESS( std::fabs( aabbIt->sqSignedDistance( intersectionPoint ) ), EPSILON * EPSILON );
}
}
}
void checkSphWallLubricationForce()
{
const uint_t timestep (timeloop_->getCurrentTimeStep()+1);
// variables for output of total force - requires MPI-reduction
pe::Vec3 forceSphr1(0);
// temporary variables
real_t gap (0);
for( auto blockIt = blocks_->begin(); blockIt != blocks_->end(); ++blockIt )
{
for( auto curSphereIt = pe::BodyIterator::begin<pe::Sphere>( *blockIt, bodyStorageID_); curSphereIt != pe::BodyIterator::end<pe::Sphere>(); ++curSphereIt )
{
pe::SphereID sphereI = ( curSphereIt.getBodyID() );
if ( sphereI->getID() == id1_ )
{
for( auto globalBodyIt = globalBodyStorage_->begin(); globalBodyIt != globalBodyStorage_->end(); ++globalBodyIt)
{
if( globalBodyIt->getID() == id2_ )
{
pe::PlaneID planeJ = static_cast<pe::PlaneID>( globalBodyIt.getBodyID() );
gap = pe::getSurfaceDistance(sphereI, planeJ);
break;
}
}
break;
}
}
}
WALBERLA_MPI_SECTION()
{
mpi::reduceInplace( gap, mpi::MAX );
}
WALBERLA_ROOT_SECTION()
{
if (gap < real_comparison::Epsilon<real_t>::value )
{
gap = walberla::math::Limits<real_t>::inf();
WALBERLA_LOG_INFO_ON_ROOT( "Sphere still too far from wall to calculate gap!" );
} else {
WALBERLA_LOG_INFO_ON_ROOT( "Gap between sphere and wall: " << gap );
}
}
// get force on sphere
for( auto blockIt = blocks_->begin(); blockIt != blocks_->end(); ++blockIt )
{
for( auto bodyIt = pe::BodyIterator::begin<pe::Sphere>( *blockIt, bodyStorageID_); bodyIt != pe::BodyIterator::end<pe::Sphere>(); ++bodyIt )
{
if( bodyIt->getID() == id1_ )
{
forceSphr1 += bodyIt->getForce();
}
}
}
// MPI reduction of pe forces over all processes
WALBERLA_MPI_SECTION()
{
mpi::reduceInplace( forceSphr1[0], mpi::SUM );
mpi::reduceInplace( forceSphr1[1], mpi::SUM );
mpi::reduceInplace( forceSphr1[2], mpi::SUM );
}
WALBERLA_LOG_INFO_ON_ROOT("Total force on sphere " << id1_ << " : " << forceSphr1);
if ( print_ )
{
WALBERLA_ROOT_SECTION()
{
std::ofstream file1;
std::string filename1("Gap_LubricationForceBody1.txt");
file1.open( filename1.c_str(), std::ofstream::app );
file1.setf( std::ios::unitbuf );
file1.precision(15);
file1 << gap << " " << forceSphr1[0] << std::endl;
file1.close();
}
}
WALBERLA_ROOT_SECTION()
{
if ( timestep == uint_t(26399) )
{
// according to the formula from Ding & Aidun 2003
// F = 6 * M_PI * rho_L * nu_L * relative velocity of both bodies=relative velocity of the sphere * r * r * 1/gap
// the correct analytically calculated value is 339.292006996217
// in this geometry setup the relative error is 0.183515322065561 %
real_t analytical = real_c(6.0) * walberla::math::M_PI * real_c(1.0) * nu_L_ * real_c(-vel_[0]) * radius_ * radius_ * real_c(1.0)/gap;
real_t relErr = std::fabs( analytical - forceSphr1[0] ) / analytical * real_c(100.0);
WALBERLA_CHECK_LESS( relErr, real_t(1) );
}
}
}
void checkSphSphLubricationForce()
{
const uint_t timestep (timeloop_->getCurrentTimeStep()+1);
// variables for output of total force - requires MPI-reduction
pe::Vec3 forceSphr1(0);
pe::Vec3 forceSphr2(0);
// temporary variables
real_t gap (0);
// calculate gap between the two spheres
for( auto blockIt = blocks_->begin(); blockIt != blocks_->end(); ++blockIt )
{
for( auto curSphereIt = pe::BodyIterator::begin<pe::Sphere>( *blockIt, bodyStorageID_); curSphereIt != pe::BodyIterator::end<pe::Sphere>(); ++curSphereIt )
{
pe::SphereID sphereI = ( curSphereIt.getBodyID() );
if ( sphereI->getID() == id1_ )
{
for( auto blockIt2 = blocks_->begin(); blockIt2 != blocks_->end(); ++blockIt2 )
{
for( auto oSphereIt = pe::BodyIterator::begin<pe::Sphere>( *blockIt2, bodyStorageID_); oSphereIt != pe::BodyIterator::end<pe::Sphere>(); ++oSphereIt )
{
pe::SphereID sphereJ = ( oSphereIt.getBodyID() );
if ( sphereJ->getID() == id2_ )
{
gap = pe::getSurfaceDistance( sphereI, sphereJ );
break;
}
}
}
break;
}
}
}
WALBERLA_MPI_SECTION()
{
mpi::reduceInplace( gap, mpi::MAX );
}
WALBERLA_ROOT_SECTION()
{
if (gap < real_comparison::Epsilon<real_t>::value )
{
// shadow copies have not been synced yet as the spheres are outside the overlap region
gap = walberla::math::Limits<real_t>::inf();
WALBERLA_LOG_INFO_ON_ROOT( "Spheres still too far apart to calculate gap!" );
} else {
WALBERLA_LOG_INFO_ON_ROOT( "Gap between sphere 1 and 2: " << gap );
}
}
// get force on spheres
for( auto blockIt = blocks_->begin(); blockIt != blocks_->end(); ++blockIt )
{
for( auto bodyIt = pe::BodyIterator::begin<pe::Sphere>( *blockIt, bodyStorageID_); bodyIt != pe::BodyIterator::end<pe::Sphere>(); ++bodyIt )
{
if( bodyIt->getID() == id1_ )
{
forceSphr1 += bodyIt->getForce();
} else if( bodyIt->getID() == id2_ )
{
forceSphr2 += bodyIt->getForce();
}
}
}
// MPI reduction of pe forces over all processes
WALBERLA_MPI_SECTION()
{
mpi::reduceInplace( forceSphr1[0], mpi::SUM );
mpi::reduceInplace( forceSphr1[1], mpi::SUM );
mpi::reduceInplace( forceSphr1[2], mpi::SUM );
mpi::reduceInplace( forceSphr2[0], mpi::SUM );
mpi::reduceInplace( forceSphr2[1], mpi::SUM );
mpi::reduceInplace( forceSphr2[2], mpi::SUM );
}
WALBERLA_LOG_INFO_ON_ROOT("Total force on sphere " << id1_ << " : " << forceSphr1);
WALBERLA_LOG_INFO_ON_ROOT("Total force on sphere " << id2_ << " : " << forceSphr2);
if ( print_ )
{
WALBERLA_ROOT_SECTION()
{
std::ofstream file1;
std::string filename1("Gap_LubricationForceBody1.txt");
file1.open( filename1.c_str(), std::ofstream::app );
file1.setf( std::ios::unitbuf );
file1.precision(15);
file1 << gap << " " << forceSphr1[0] << std::endl;
file1.close();
std::ofstream file2;
std::string filename2("Gap_LubricationForceBody2.txt");
file2.open( filename2.c_str(), std::ofstream::app );
file2.setf( std::ios::unitbuf );
file2.precision(15);
file2 << gap << " " << forceSphr2[0] << std::endl;
file2.close();
}
}
WALBERLA_ROOT_SECTION()
{
if ( timestep == uint_t(1000) )
{
// both force x-components should be the same only with inverted signs
WALBERLA_CHECK_FLOAT_EQUAL ( forceSphr2[0], -forceSphr1[0] );
// according to the formula from Ding & Aidun 2003
// F = 3/2 * M_PI * rho_L * nu_L * relative velocity of both spheres * r * r * 1/gap
// the correct analytically calculated value is 339.2920063998
// in this geometry setup the relative error is 0.1246489711 %
real_t analytical = real_c(3.0)/real_c(2.0) * walberla::math::M_PI * real_c(1.0) * nu_L_ * real_c(2.0) * real_c(vel_[0]) * radius_ * radius_ * real_c(1.0)/gap;
real_t relErr = std::fabs( analytical - forceSphr2[0] ) / analytical * real_c(100.0);
WALBERLA_CHECK_LESS( relErr, real_t(1) );
}
}
}
