Negative mesh Jacobians detected
Hello everyone, I am a new guy in Gmsh. When I generate grid, it comes out 'Negative mesh Jacobians detected'. Could someone tell me how to deal with this problem? The geo file is as follows:
LC=0.001;
Point(1) = {0, 0.5, 0, LC};
Point(2) = {-0.5, 0, 0, LC};
Point(3) = {0, -0.5, 0, LC};
Point(4) = {0.5, 0, 0, LC};
Point(5) = {0, 5.0, 0, 1};
Point(6) = {-5.0, 0, 0, 1};
Point(7) = {0, -5.0, 0, 1};
Point(8) = {5.0, 0, 0, 1};
Point(9) = {0, 0, 0, 1};
//+
Point(10) = {-24, -20, 0, 2};
//+
Point(11) = {36, -20, 0, 2};
//+
Point(12) = {36, 20, 0, 2};
//+
Point(13) = {-24, 20, 0, 2};//+
Circle(1) = {1, 9, 2};
//+
Circle(2) = {2, 9, 3};
//+
Circle(3) = {3, 9, 4};
//+
Circle(4) = {4, 9, 1};
//+
Circle(5) = {5, 9, 6};
//+
Circle(6) = {6, 9, 7};
//+
Circle(7) = {7, 9, 8};
//+
Circle(8) = {8, 9, 5};
//+
Line(9) = {13, 10};
//+
Line(10) = {10, 11};
//+
Line(11) = {11, 12};
//+
Line(12) = {12, 13};
//+
Line(13) = {1, 5};
//+
Line(14) = {2, 6};
//+
Line(15) = {3, 7};
//+
Line(16) = {4, 8};
//+
Curve Loop(1) = {13, 1, -14, -5};
//+
Plane Surface(1) = {1};
//+
Curve Loop(2) = {14, 2, -15, -6};
//+
Plane Surface(2) = {2};
//+
Curve Loop(3) = {3, -16, -7, 15};
//+
Plane Surface(3) = {3};
//+
Curve Loop(4) = {4, -13, -8, 16};
//+
Plane Surface(4) = {4};
//+
Curve Loop(5) = {12, 9, 10, 11};
//+
Curve Loop(6) = {5, 6, 7, 8};
//+
Plane Surface(5) = {5, 6};
//+
Transfinite Curve {13, 1, 14, 2, 3, 4, 16, 15, 7, 8, 5, 6} = 41 Using Progression 1;
//+
Transfinite Surface {1};
//+
Transfinite Surface {2};
//+
Transfinite Surface {3};
//+
Transfinite Surface {4};
//+
Recombine Surface {1, 2, 3, 4};
//+
Physical Curve("inflow", 17) = {9, 12, 10};
//+
Physical Curve("outflow", 18) = {11};
//+
Physical Surface("fluid", 20) = {5, 4, 1, 2, 3};
//+
Physical Curve("wall", 21) = {1, 2, 3, 4};
With best regards
Edited by Christophe Geuzaine