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Adding an arbitrary shaped particle.

OpenLB – Open Source Lattice Boltzmann Code Forums on OpenLB General Topics Adding an arbitrary shaped particle.

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  • #8614
    avrachan1
    Participant

    Dear Community,

    I used the following function to create a particle of an arbitrary shape.

    129 template <typename T, typename DESCRIPTOR>
    130 class myindicator : public IndicatorF3D<T>
    131 {
    132 private :
    133 SuperLattice<T,DESCRIPTOR>& sLattice;
    134 public :
    135 myindicator(SuperLattice<T,DESCRIPTOR>& _sLattice) : IndicatorF3D<T>(), sLattice(_sLattice)
    136 {
    137 ;
    138 this->getName() = “myindicator”;
    139 };
    140
    141 bool operator()(bool output, T X, T Y,T Z)
    142 {
    143
    144 int latticeR[4];
    145 T physR[3];
    146 physR[0]=X;
    147 physR[1]=Y;
    148 physR[2]=Z;
    149 sLattice.getCuboidGeometry().getLatticeR(latticeR,physR);
    150 T phi=sLattice.getBlock(latticeR[0]).get(latticeR[1],latticeR[2],latticeR[3]).computeRho();
    151 //std::cout<<phi<<“\t”<<latticeR[0]<<“\n”;
    152 if(phi>0.5)
    153 return true;
    154 else
    155 return false;
    156 };
    157 };

    440 std::shared_ptr<IndicatorF3D<T>> particle = std::make_shared<myindicator<T,DESCRIPTOR>>( sLattice);
    444 creators::addResolvedArbitraryShape3D(particleSystem,center,dx,particle,width,1000.);

    However, this fails at line 314 of IndicatorBase3D.hh file in the function signedDistance().

    As I understand, I need to provide a function to compute the signed distance from the surface of my arbitrary shaped particle.

    Am I correct?

    • This topic was modified 1 week, 6 days ago by avrachan1.
    • This topic was modified 1 week, 6 days ago by avrachan1.
    #8621
    avrachan1
    Participant

    Even if I try to create a simple shape composed of two overlapping spheres, I get the same error

    Vector<T,3> center(lengthX/2.,lengthY/2.,lengthZ/2.);
    442 std::shared_ptr<IndicatorSphere3D<T>> sphere1 ( new IndicatorSphere3D<T> (center,5*dx));
    443 center[0]=center[0]+5*dx;
    444 std::shared_ptr<IndicatorSphere3D<T>> sphere2 ( new IndicatorSphere3D<T> (center,5*dx));
    445 //IndicatorIdentity3D<T> combined(sphere1+sphere2);
    446 std::shared_ptr<IndicatorF3D<T>> cuboid2 = std::make_shared<IndicatorIdentity3D<T>>(sphere1+sphere2);
    447
    448 creators::addResolvedArbitraryShape3D(particleSystem,center,dx,cuboid2,2.*W0,1000.);

    What am I doing wrong ?

    PS: How do I paste code in the forum?

    • This reply was modified 1 week, 6 days ago by avrachan1.
    #8632
    jan
    Participant

    Dear avrachan,

    the indicator that is passed to creators::addResolvedArbitraryShape3D must provide a signedDistance method. In the second case, when combining two indicators, please try to use the functions provided in src/functors/analytical/indicator/indicComb3D.h. For example, you could use the IndicPlus3D.

    To highlight code in the forum, you have to use the backtick (https://en.wikipedia.org/wiki/Backtick) and enclose the code within it.

    Best regards,
    Jan

    #8641
    avrachan1
    Participant

    Dear Jan,

    That works. My idea is to make the arbitrary shaped particle by adding cuboids of various sizes.

    Thanks.

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