/*
Wind tunnel with a step
*/

h = 1.0;
l = 3.0;
lstep = 0.6;
hstep = 0.2;
lcext = 1/40;
lcstep = lcext;

Point (1) = {0,0,0,lcext*1.5};
Point (2) = {0,h,0,lcext*1.5};
Point (3) = {l,h,0,lcext};
Point (4) = {l,hstep,0,lcext};
Point (5) = {lstep,hstep,0,lcstep};
Point (6) = {lstep,0,0,lcext};
Point (7) = {lstep,h,0,lcstep};
Point (8) = {0,hstep,0,lcext};
Line(1) = {4,3};
Line(2) = {3,7};
Line(3) = {7,5};
Line(4) = {5,4};
Line(5) = {8,5};
Line(6) = {6,5};
Line(7) = {6,1};
Line(8) = {1,8};
Line(9) = {8,2};
Line(10) = {2,7};
Line Loop(11) = {4,1,2,3};
Plane Surface(1) = {11};
Line Loop(13) = {-5,9,10,3};
Plane Surface(2) = {13};
Line Loop(15) = {-6,7,8,5};
Plane Surface(3) = {15};
N = 21;
Transfinite Line {7,5,10} = N*lstep;
Transfinite Line {9,3,1}  = N*(h-hstep);
Transfinite Line {4,2}  = N*(l-lstep);
Transfinite Line {8,6}  = N*(hstep);
Transfinite Surface {1} = {4,3,7,5};
Transfinite Surface {2} = {8,5,7,2};
Transfinite Surface {3} = {1,8,5,6};
Recombine Surface {1,2,3};