aamove.edp

FreeFem++可以生成高质量的有限元网格。可以用于流体力学

verbosity=4;
border a(t=0,1){x=t;y=0;label=1;};
border b(t=0,0.5){x=1;y=t;label=1;};
border c(t=0,0.5){x=1-t;y=0.5;label=1;};
border d(t=0.5,1){x=0.5;y=t;label=1;};
border e(t=0.5,1){x=1-t;y=1;label=1;};
border f(t=0,1){x=0;y=1-t;label=1;};
func uu= sin(y*pi)/10;
func vv= cos(x*pi)/10;

mesh Th = buildmesh ( a(6) + b(4) + c(4) +d(4) + e(4) + f(6));
Th=movemesh(Th,[x+uu,y+vv]);
plot(Th,wait=1,fill=1);
fespace Vh(Th,P2);

Vh u,v;

u=0;
func ff= 1;
func gg= 0;
int i=0;
problem Probem1(u,v,solver=LU,init=i,eps=-1.0e-6) =
    int2d(Th)(  dx(u)*dx(v) + dy(u)*dy(v)) 
  + int2d(Th) ( v*ff ) 
  + on(1,u=gg)  ;
  
real cpu=clock();
Probem1; // SOLVE THE PROBLEM 1
plot(u,wait=1);
cout << " CPU = " << clock()-cpu << endl;