bug-mesh.edp

FreeFem++可以生成高质量的有限元网格。可以用于流体力学

real x0=2.2,r=2.1, err0=5e-3;

border aa(t=0, 2*pi) {    x = 5*cos(t);    y = 5*sin(t);  };
border dd(t=-r+0.1,r-0.1){ x=x0+t/sqrt(2.0); y=t/sqrt(2.0);};
int n=7; mesh th = buildmesh(aa(5*n)+dd(6*n));

 plot(th);
fespace Vh(th,P1);
Vh    u,uh,p, f=1;

problem A(u,uh) =int2d(th)(dx(u)*dx(uh)+dy(u)*dy(uh))
        -int2d(th)(f*uh) + on(aa,u=0);


for(n=2;n<5;n++){
 A;
 th = adaptmesh(th,u,err=err0/n); plot(th,wait=1);
 u=u;
 plot(u,value=1,wait=1);
}