| 44 |  | * | 
| 45 |  | *  Created by Charles F. Vardeman II on 29 July 2008. | 
| 46 |  | *  @author  Charles F. Vardeman II | 
| 47 | < | *  @version $Id: Triangle.cpp,v 1.2 2008-12-05 16:20:38 chuckv Exp $ | 
| 47 | > | *  @version $Id: Triangle.cpp,v 1.3 2009-05-13 22:27:29 gezelter Exp $ | 
| 48 |  | * | 
| 49 |  | */ | 
| 50 |  |  | 
| 53 |  | using namespace oopse; | 
| 54 |  |  | 
| 55 |  |  | 
| 56 | < | Triangle::Triangle() : HaveNormal_(false), HaveCentroid_(false),HaveArea_(false), area_(0.0), normal_(V3Zero), | 
| 57 | < | centroid_(V3Zero),facetVelocity_(V3Zero), mass_(0.0), | 
| 58 | < | a_(V3Zero),b_(V3Zero),c_(V3Zero){ | 
| 56 | > | Triangle::Triangle() : HaveNormal_(false), HaveCentroid_(false), | 
| 57 | > | HaveArea_(false), area_(0.0), normal_(V3Zero), | 
| 58 | > | centroid_(V3Zero), facetVelocity_(V3Zero), mass_(0.0), | 
| 59 | > | a_(V3Zero), b_(V3Zero), c_(V3Zero){ | 
| 60 |  | } | 
| 61 |  |  | 
| 62 |  | void Triangle::addVertices(Vector3d P1, Vector3d P2, Vector3d P3){ | 
| 88 |  | centroid_ = (vertices_[0] + vertices_[1] + vertices_[2])/3.0; | 
| 89 |  | return centroid_; | 
| 90 |  | } | 
| 91 | + |  | 
| 92 | + |  | 
| 93 | + | Mat3x3d Triangle::computeHydrodynamicTensor(RealType viscosity) { | 
| 94 | + |  | 
| 95 | + | Vector3d u0 = -a_; | 
| 96 | + | Vector3d v0 = centroid_ - vertices_[0]; | 
| 97 | + | RealType s0 = 0.5*cross(u0,v0).length(); | 
| 98 | + |  | 
| 99 | + | Vector3d u1 = -c_; | 
| 100 | + | Vector3d v1 = centroid_ - vertices_[1]; | 
| 101 | + | RealType s1 = 0.5*cross(u1,v1).length(); | 
| 102 | + |  | 
| 103 | + | Vector3d u2 = b_; | 
| 104 | + | Vector3d v2 = centroid_ - vertices_[2]; | 
| 105 | + | RealType s2 = 0.5*cross(u2,v2).length(); | 
| 106 | + |  | 
| 107 | + | Mat3x3d H; | 
| 108 | + | H = hydro_tensor(centroid_,centroid_,vertices_[1],vertices_[0],s0,viscosity)+ | 
| 109 | + | hydro_tensor(centroid_,centroid_,vertices_[1],vertices_[2],s1,viscosity)+ | 
| 110 | + | hydro_tensor(centroid_,centroid_,vertices_[2],vertices_[0],s2,viscosity); | 
| 111 | + |  | 
| 112 | + | return H.inverse(); | 
| 113 | + | } | 
| 114 | + |  | 
| 115 | + | Mat3x3d Triangle::hydro_tensor( | 
| 116 | + | const Vector3d& ri, | 
| 117 | + | const Vector3d& rj0, | 
| 118 | + | const Vector3d& rj1, | 
| 119 | + | const Vector3d& rj2, | 
| 120 | + | RealType s, RealType viscosity){ | 
| 121 | + |  | 
| 122 | + | Vector3d v2 = (rj0 + rj1 + rj2)/3.0;  // sub-centroid | 
| 123 | + | Vector3d dr = ri - v2;                // real centroid to sub-centroid | 
| 124 | + | RealType l2 = 1.0/dr.lengthSquare(); | 
| 125 | + |  | 
| 126 | + | Mat3x3d G; | 
| 127 | + | G = (SquareMatrix3<RealType>::identity() + outProduct(dr,dr)*l2)*sqrt(l2); | 
| 128 | + |  | 
| 129 | + | G *= 0.125/3.14159285358979; | 
| 130 | + | G *= s/viscosity; | 
| 131 | + | return G; | 
| 132 | + | } |