Then we use the <code>Circle arc</code> entity, which is found in the same category as
<code>%Point</code> and <code>Lines</code>. The file reads "Circle"
but the difference to note is that this function uses three points to
-make an arc of a circle, namely the starting point, center, and ending point.
-Splitting the circle into four arcs like this allows for more freedom when declaring the
-boundary IDs. Constructing a circle from four arcs then looks as follows
+make an arc of a circle, namely the starting point, center, and ending point. The
+angle of an arc is required to be less than 180 degrees. We therefore split the circle
+into four arcs, which also allows us to set different boundary IDs.
+This then looks as follows
where point 31 is the common center for all arcs:
@code
Circle(51) = {33, 31, 103};
@endcode
-For the second circle, we use the alternate <code>Circle</code> entity, which requires the origin, radius,
-and starting and ending angle respectively.
-
-@code
-radius1 = .5;
-Circle(12) = {0.42, 2.0, 0, radius1, 0, 2*Pi};
-@endcode
+We follow the same procedure for the second circle.
<h5>Plane surfaces</h5>
This can easily be traced back by following along with the numbers in the braces.
@code
-Curve Loop(1) = {40, -43, 14, 57, 59, 60, 58};
-Curve Loop(2) = {12};
+Curve Loop(1) = {40, -43, 10, 57, 59, 60, 58};
+Curve Loop(2) = {12, 13, 14, 15};
Plane Surface(1) = {1, 2};
@endcode
Point(7) = {-0.98, 0, 0, 1.0};
Point(8) = {-0.98 - b, -0.2, 0, 1.0};
Point(9) = {-3.5, -0.2, 0, 1.0};
-Point(14) = {3.5, 0, 0, 1.0}; // Tip of slit on left hand side
+Point(10) = {3.5, 0, 0, 1.0}; // Tip of slit on left hand side
// The 2 points below are for separating the left and right side of the mesh
Point(36) = {-0.98, 3.36, 0, 1.0};
Line(7) = {7, 8};
Line(8) = {8, 9};
Line(9) = {9, 1};
-Line(14) = {7, 14}; // Line that bisects domain from top/bottom
+Line(10) = {7, 10}; // Line that bisects domain from top/bottom
// Lines on the bottom/top domain
Line(38) = {1, 37};
Line(53) = {107, 109};
Line(54) = {109, 110};
Line(55) = {110, 108};
-Line(56) = {108, 14};
-Line(57) = {14, 111};
+Line(56) = {108, 10};
+Line(57) = {10, 111};
Line(58) = {112, 3};
Line(59) = {111, 113};
Line(60) = {113, 112};
Point(103) = {-1.4, -1.54, 0, 1.0}; // right point
Point(104) = {-2.8, -1.54, 0, 1.0}; // left point
-// Bottom left hole
+// Bottom left hole arcs
Circle(48) = {103, 31, 32};
Circle(49) = {32, 31, 104};
Circle(50) = {104, 31, 33};
Circle(51) = {33, 31, 103};
-// The upper right circle
+// Similarly, the upper right circle
radius1 = .5;
Point(19) = {0.42, 2.0, 0, 1.0}; // origin
-Point(22) = {0.42, 2.0 + radius1, 0, 1.0}; // top point
-Point(23) = {0.42, 2.0 - radius1, 0, 1.0}; // bottom point
-Circle(12) = {0.42, 2.0, 0, radius1, 0, 2*Pi};
+Point(20) = {0.42, 2.0 - radius1, 0, 1.0};
+Point(21) = {0.42 + radius1, 2.0, 0, 1.0};
+Point(22) = {0.42, 2.0 + radius1, 0, 1.0};
+Point(23) = {0.42 - radius1, 2.0, 0, 1.0};
+Circle(12) = {20, 19, 21};
+Circle(13) = {21, 19, 22};
+Circle(14) = {22, 19, 23};
+Circle(15) = {23, 19, 20};
//---------------------------------------------------------------------------
// This section describes the "Plane Surfaces", i.e., the 2D surfaces for meshing
// The surface of the top right partition
-Curve Loop(1) = {40, -43, 14, 57, 59, 60, 58};
-Curve Loop(2) = {12};
+Curve Loop(1) = {40, -43, 10, 57, 59, 60, 58};
+Curve Loop(2) = {12, 13, 14, 15};
Plane Surface(1) = {1, 2};
// Surface of the bottom right partition
-Curve Loop(3) = {39, 52, 53, 54, 55, 56, -14, -42};
+Curve Loop(3) = {39, 52, 53, 54, 55, 56, -10, -42};
Plane Surface(2) = {3};
// Surface of bottem left mesh