ForceSelfTest.cpp File Reference

#include "DPMBase.h"
#include "Walls/InfiniteWall.h"
#include "Species/Species.h"
#include "Species/LinearViscoelasticSlidingFrictionSpecies.h"

Classes
class	ParticleParticleCollision
class	WallParticleCollision

Functions
void	particleParticleTest ()
void	wallParticleTest ()
int	main ()

Function Documentation

main()

int main

(

)

{
    
    logger(INFO, "\nnote: analytic values are only asymptotically correct as delta->0");
    particleParticleTest();
    wallParticleTest();
    return 0;
}

References INFO, logger, particleParticleTest(), and wallParticleTest().

particleParticleTest()

void particleParticleTest

(

)

{
    logger(INFO, "\ntesting particle-particle collisions ...\n\n", Flusher::NO_FLUSH);
    
    ParticleParticleCollision problem;
    
    problem.random.setRandomSeed(5);
    
    problem.setupInitialConditions();
    Mdouble normalRelativeVelocity, tangentialRelativeVelocity, analyticTangentialRelativeVelocity;
    
    logger(INFO, "5: without tangential forces");
    problem.setName("ForceSelfTest5");
    problem.solve();
    problem.getRelativeVelocityComponents(normalRelativeVelocity, tangentialRelativeVelocity);
    logger(INFO, "tangentialRelativeVelocity: analytic=%, simulation=%\n",
           problem.initialTangentialRelativeVelocity, tangentialRelativeVelocity, Flusher::NO_FLUSH);
    logger(INFO, "normalRelativeVelocity: analytic=%, simulation=%",
           -problem.en * problem.initialNormalRelativeVelocity, normalRelativeVelocity);
    
    //problem.setAppend_to_files(true);
    
    logger(INFO, "6: with Coulomb friction");
    Mdouble mu = problem.random.getRandomNumber(0.0, 1.0);
    problem.species->setSlidingFrictionCoefficient(mu);
    problem.species->setSlidingDissipation(1e20);
    //problem.species->setSlidingStiffness(0.0);
    problem.setName("ForceSelfTest6");
    problem.solve();
    problem.getRelativeVelocityComponents(normalRelativeVelocity, tangentialRelativeVelocity);
    analyticTangentialRelativeVelocity = std::max(0.0, problem.initialTangentialRelativeVelocity +
                                                       mu * 3.5 * (1 + problem.en) *
                                                       problem.initialNormalRelativeVelocity);
    logger(INFO, "tangentialRelativeVelocity: analytic=%, simulation=%\n",
           analyticTangentialRelativeVelocity, tangentialRelativeVelocity, Flusher::NO_FLUSH);
    logger(INFO, "normalRelativeVelocity: analytic=%, simulation=%",
           -problem.en * problem.initialNormalRelativeVelocity, normalRelativeVelocity);
    
    logger(INFO, "7: with Coulomb friction, spring activated");
    problem.species->setSlidingStiffness(1.0);
    //problem.species->setSlidingDissipation(1);
    problem.setName("ForceSelfTest7");
    problem.solve();
    logger(INFO, "tangentialRelativeVelocity: analytic=%, simulation=%\n",
           analyticTangentialRelativeVelocity, tangentialRelativeVelocity, Flusher::NO_FLUSH);
    logger(INFO, "normalRelativeVelocity: analytic=%, simulation=%",
           -problem.en * problem.initialNormalRelativeVelocity, normalRelativeVelocity);
    
    logger(INFO, "8: with tangential viscous force");
    Mdouble et = problem.random.getRandomNumber(-1.0, 0.0);
    problem.species->setSlidingFrictionCoefficient(1e20);
    problem.species->setSlidingDissipation(-log(-et) / (2.0 * problem.tc) / 3.5 * 2.0 * problem.m12);
    problem.species->setSlidingStiffness(0.0);
    problem.setName("ForceSelfTest8");
    problem.solve();
    problem.getRelativeVelocityComponents(normalRelativeVelocity, tangentialRelativeVelocity);
    analyticTangentialRelativeVelocity = problem.initialTangentialRelativeVelocity *
                                         exp(-2.0 * 3.5 * problem.species->getSlidingDissipation() /
                                             (2.0 * problem.m12) * problem.getCollisionTime(2.0 * problem.m12));
    logger(INFO, "tangentialRelativeVelocity: analytic=%, simulation=%\n",
           analyticTangentialRelativeVelocity, tangentialRelativeVelocity, Flusher::NO_FLUSH);
    logger(INFO, "normalRelativeVelocity: analytic=%, simulation=%",
           -problem.en * problem.initialNormalRelativeVelocity, normalRelativeVelocity);
    
    logger(INFO, "9: with tangential elastic force");
    Mdouble et2 = problem.random.getRandomNumber(0.0, 1.0);
    problem.species->setSlidingFrictionCoefficient(1e20);
    problem.species->setSlidingDissipation(0.0);
    problem.species->setSlidingStiffness(
            problem.species->getStiffness() / 3.5 * mathsFunc::square(acos(-et2) / constants::pi));
    problem.setName("ForceSelfTest9");
    problem.solve();
    problem.getRelativeVelocityComponents(normalRelativeVelocity, tangentialRelativeVelocity);
    analyticTangentialRelativeVelocity = problem.initialTangentialRelativeVelocity *
                                         cos(sqrt(problem.species->getSlidingStiffness() / problem.m12 * 3.5) *
                                             problem.getCollisionTime(2.0 * problem.m12));
    logger(INFO, "tangentialRelativeVelocity: analytic=%, simulation=%\n",
           analyticTangentialRelativeVelocity, tangentialRelativeVelocity, Flusher::NO_FLUSH);
    logger(INFO, "normalRelativeVelocity: analytic=%, simulation=%",
           -problem.en * problem.initialNormalRelativeVelocity, normalRelativeVelocity);
}

References mathsFunc::cos(), ParticleParticleCollision::en, mathsFunc::exp(), ParticleParticleCollision::getCollisionTime(), RNG::getRandomNumber(), ParticleParticleCollision::getRelativeVelocityComponents(), INFO, ParticleParticleCollision::initialNormalRelativeVelocity, ParticleParticleCollision::initialTangentialRelativeVelocity, mathsFunc::log(), logger, ParticleParticleCollision::m12, NO_FLUSH, constants::pi, DPMBase::random, DPMBase::setName(), RNG::setRandomSeed(), ParticleParticleCollision::setupInitialConditions(), DPMBase::solve(), ParticleParticleCollision::species, mathsFunc::square(), and ParticleParticleCollision::tc.

Referenced by main().

wallParticleTest()

void wallParticleTest

(

)

{
    logger(INFO, "\ntesting wall-particle collisions ...\n");
    
    srand(5);
    
    WallParticleCollision problem;
    problem.setupInitialConditions();
    
    Mdouble normalRelativeVelocity, tangentialRelativeVelocity, analyticTangentialRelativeVelocity;
    
    //problem.setAppend_to_files(true);
    
    logger(INFO, "0: without tangential forces");
    problem.setName("ForceSelfTest0");
    problem.solve();
    
    problem.getRelativeVelocityComponents(normalRelativeVelocity, tangentialRelativeVelocity);
    logger(INFO, "tangentialRelativeVelocity: analytic=%, simulation=%\n",
           problem.initialTangentialRelativeVelocity, tangentialRelativeVelocity, Flusher::NO_FLUSH);
    logger(INFO, "normalRelativeVelocity: analytic=%, simulation=%",
           -problem.en * problem.initialNormalRelativeVelocity, normalRelativeVelocity);
    
    logger(INFO, "1: with Coulomb friction");
    Mdouble mu = problem.random.getRandomNumber(0.0, 1.0);
    problem.species->setSlidingFrictionCoefficient(mu);
    problem.species->setSlidingDissipation(1e20);
    problem.species->setSlidingStiffness(0.0);
    problem.setName("ForceSelfTest1");
    problem.solve();
    problem.getRelativeVelocityComponents(normalRelativeVelocity, tangentialRelativeVelocity);
    analyticTangentialRelativeVelocity = std::max(0.0, problem.initialTangentialRelativeVelocity +
                                                       mu * 3.5 * (1 + problem.en) *
                                                       problem.initialNormalRelativeVelocity);
    logger(INFO, "tangentialRelativeVelocity: analytic=%, simulation=%\n",
           analyticTangentialRelativeVelocity, tangentialRelativeVelocity, Flusher::NO_FLUSH);
    logger(INFO, "normalRelativeVelocity: analytic=%, simulation=%",
           -problem.en * problem.initialNormalRelativeVelocity, normalRelativeVelocity);
    
    logger(INFO, "2: with Coulomb friction, spring activated");
    problem.species->setSlidingStiffness(1.0);
    problem.setName("ForceSelfTest2");
    problem.solve();
    logger(INFO, "tangentialRelativeVelocity: analytic=%, simulation=%\n",
           problem.initialTangentialRelativeVelocity, tangentialRelativeVelocity, Flusher::NO_FLUSH);
    logger(INFO, "normalRelativeVelocity: analytic=%, simulation=%",
           -problem.en * problem.initialNormalRelativeVelocity, normalRelativeVelocity);
    
    logger(INFO, "3: with tangential viscous force");
    Mdouble et = problem.random.getRandomNumber(-1.0, 0.0);
    problem.species->setSlidingFrictionCoefficient(1e20);
    problem.species->setSlidingDissipation(-log(-et) / (2.0 * problem.tc) / 3.5 * 2.0 * problem.m12);
    problem.species->setSlidingStiffness(0.0);
    problem.setName("ForceSelfTest3");
    problem.solve();
    problem.getRelativeVelocityComponents(normalRelativeVelocity, tangentialRelativeVelocity);
    analyticTangentialRelativeVelocity = problem.initialTangentialRelativeVelocity *
                                         exp(-2.0 * 3.5 * problem.species->getSlidingDissipation() /
                                             (2.0 * problem.m12) * problem.getCollisionTime(2.0 * problem.m12));
    logger(INFO, "tangentialRelativeVelocity: analytic=%, simulation=%\n",
           problem.initialTangentialRelativeVelocity, tangentialRelativeVelocity, Flusher::NO_FLUSH);
    logger(INFO, "normalRelativeVelocity: analytic=%, simulation=%",
           -problem.en * problem.initialNormalRelativeVelocity, normalRelativeVelocity);
    
    logger(INFO, "4: with tangential elastic force");
    Mdouble et2 = problem.random.getRandomNumber(0.0, 1.0);
    problem.species->setSlidingFrictionCoefficient(1e20);
    problem.species->setSlidingDissipation(0.0);
    problem.species->setSlidingStiffness(
            problem.species->getStiffness() / 3.5 * mathsFunc::square(acos(-et2) / constants::pi));
    problem.setName("ForceSelfTest4");
    problem.solve();
    problem.getRelativeVelocityComponents(normalRelativeVelocity, tangentialRelativeVelocity);
    analyticTangentialRelativeVelocity = problem.initialTangentialRelativeVelocity *
                                         cos(sqrt(problem.species->getSlidingStiffness() / problem.m12 * 3.5) *
                                             problem.getCollisionTime(2.0 * problem.m12));
    logger(INFO, "tangentialRelativeVelocity: analytic=%, simulation=%\n",
           problem.initialTangentialRelativeVelocity, tangentialRelativeVelocity, Flusher::NO_FLUSH);
    logger(INFO, "normalRelativeVelocity: analytic=%, simulation=%",
           -problem.en * problem.initialNormalRelativeVelocity, normalRelativeVelocity);
}

References mathsFunc::cos(), ParticleParticleCollision::en, mathsFunc::exp(), ParticleParticleCollision::getCollisionTime(), RNG::getRandomNumber(), WallParticleCollision::getRelativeVelocityComponents(), INFO, ParticleParticleCollision::initialNormalRelativeVelocity, ParticleParticleCollision::initialTangentialRelativeVelocity, mathsFunc::log(), logger, ParticleParticleCollision::m12, NO_FLUSH, constants::pi, DPMBase::random, DPMBase::setName(), WallParticleCollision::setupInitialConditions(), DPMBase::solve(), ParticleParticleCollision::species, mathsFunc::square(), and ParticleParticleCollision::tc.

Referenced by main().