New Particle Collision Model 0penLB 1.6

[Jijo]

Dear OpenLB community,

I have tried the new particle collision model but I failed in validating the model with experimental studies (Single spherical Particle-wall Collision). The snippet of the code:

// Discretization Settings
int res = 50;
T const charLatticeVelocity = 0.03;

// Time Settings
T const maxPhysT = 0.45; // max. simulation time in s
T const iTwrite = 1E-3; // write out intervall in s

// Domain Settings
T const lengthX = 0.11;
T const lengthY = 0.11;
T const lengthZ = 0.20;

// Fluid Settings
T const physDensity = 1141.;
T const physViscosity = 0.008/1141.;

//Particle Settings
T Radius = 10.0/1000.0;
T const SphereDensity = 2170.;
T const PositionX = 0.055;
T const Positiony = 0.055;
T const PositionZ = 0.16;

Vector<T,3> SpherePosition = {PositionX,PositionX,PositionZ};
Vector<T,3> SphereVelocity = {0.,0.,0.};
Vector<T,3> externalAcceleration = {.0, .0, -9.81 * (1. – physDensity / SphereDensity)};

// Characteristic Quantities
T const charPhysLength = lengthX;
T const charPhysVelocity = 0.66; // Assumed maximal velocity

unsigned contactBoxResolutionPerDirection = 16;
unsigned particleContactMaterial = 0;
unsigned wallContactMaterial = 0;
T youngsModulus = 575e6;
T poissonRatio = 0.25;
T dampingConstant = 0.1;
T coefficientStaticFriction = 0.02;
T coefficientKineticFriction = 0.3;

/// End of the code

The rest is similar to the settlingcube3D example. I do not see any rebound of the particle even if I increase the time step or the grid size. I read the published paper but I could not fix the issue. Any help here?

Regards,

[jan]

Dear Jijo,

as stated in [1], it is necessary to enlarge the particle for the consideration of the contact. You can do this using particle.setField<NUMERICPROPERTIES, ENLARGEMENT_FOR_CONTACT>( /* choose a value */ );. Otherwise it is to be expected that the incompressible fluid slows down the particle so that there is no contact with the wall, especially for high resolutions.

Kind regards,
Jan

[1]: 10.1016/j.partic.2022.12.005

[Author]

Posts