Dear Experts I have a problem with the Dirichlet boundary conditions for solving a partial differential equation that represent the potential flow in a duct. The duct is particular duct (Bovet) and showed in the code below.
The problem is that the curve on the left (the smallest) is the sum of two curves (the overall curve is NOT a function) and I do not understand how define a list of boundaries along alla the contour that represent the Dirichlet conditions.
I used the function ImplicitRegion to define the region where the PDE will be solved, but it does not work.
Many thanks,
Antonio

CODE

par = 0.25;
par1 = +0.25;
Fint[x_] := 1.5 + 0.5*x^2 - x^2*(Tan[(x)*\[Pi]/2])^0.1;
(*Plot[Fint[x],{x,0.0,1},PlotRange->{{0,2},{0,2}},AspectRatio\[Rule]1]\
*)

a = .14;
Fest1[x_] := 1 - (x^2 + a^.5 - (a - x)^0.5) + x/(2*a^.5);
Fest2[x_] := 0.95*(x^0.5 + a^.5 - (a - x)^0.5);
Yintmax = Fest1[0];
Yintuguale1 = Fest1[a];
Yintuguale2 = Fest2[a];
diff = Yintuguale1 - Yintuguale2
Fest1[x_] := 
  1 - diff - 0.015 - (x^2 + a^.5 - (a - x)^0.5) + x/(2*a^.5);
Plot[{Fint[x], Fest1[x], Fest2[x]}, {x, 0.0, 1}, 
 PlotRange -> {{0, 2}, {0, 2}}, AspectRatio -> 1]