commit d3608d1cdb95bb9f7472ce6ab7b73070b2bff7dd
Author: erickahmed <engineering@erickahmed.com>
Date:   Fri Apr 18 16:41:46 2025 +0200

    Add venturi duct for wind turbine rotor

diff --git a/venturi/de-lavale-duct.scad b/venturi/de-lavale-duct.scad
new file mode 100644
index 0000000..6068b35
--- /dev/null
+++ b/venturi/de-lavale-duct.scad
@@ -0,0 +1,96 @@
+// Inlet variables
+inlet_length  = 10;
+inlet_radius  = 10;
+inlet_throat_radius = 3;
+inlet_thickness     = 0.25;
+inlet_segments      = 30;  // Number of stacked layers (higher = smoother)
+inlet_curve_factor  = 2;   // Controls how aggressively the walls curve
+
+module inlet() {
+    difference() {
+        union() {
+            for (i = [0:inlet_segments-1]) {
+                h = inlet_length / inlet_segments;
+                t = i / (inlet_segments-1);
+                
+                // Apply power function for curvature
+                r1 = inlet_throat_radius + (inlet_radius - inlet_throat_radius) * pow(t, inlet_curve_factor);
+                r2 = inlet_throat_radius + (inlet_radius - inlet_throat_radius) * pow((i+1) / (inlet_segments-1), inlet_curve_factor);
+
+                translate([0, 0, i * h])
+                cylinder(h = h, r1 = r1, r2 = r2, $fn = 75);
+            }
+        }
+
+        // Inner subtraction (to maintain thickness)
+        union() {
+            for (i = [0:inlet_segments-1]) {
+                h = inlet_length / inlet_segments;
+                t = i / (inlet_segments-1);
+                
+                r1 = (inlet_throat_radius + (inlet_radius - inlet_throat_radius) * pow(t, inlet_curve_factor)) - inlet_thickness;
+                r2 = (inlet_throat_radius + (inlet_radius - inlet_throat_radius) * pow((i+1) / (inlet_segments-1), inlet_curve_factor)) - inlet_thickness;
+
+                translate([0, 0, i * h])
+                cylinder(h = h, r1 = r1, r2 = r2, $fn = 75);
+            }
+        }
+
+        // Plate at the start of the inlet (sealed)
+        translate([0, 0, -inlet_thickness])  // Align the plate to the front of the inlet
+        cylinder(h = inlet_thickness, r = inlet_radius, $fn = 75);  // Plate at the inlet (front)
+    }
+}
+
+// Rotate for correct orientation
+rotate([0, -90, 0]) inlet();
+
+
+
+
+// Outlet variables
+outlet_length  = 50;
+outlet_radius  = 10;
+outlet_throat_radius = 3;
+outlet_thickness     = 0.25;
+outlet_segments      = 20;  // Number of stacked layers (higher = smoother)
+outlet_curve_factor  = 1.5;   // Controls how aggressively the walls curve
+
+module outlet() {
+    difference() {
+        union() {
+            for (i = [0:outlet_segments-1]) {
+                h = outlet_length / outlet_segments;
+                t = i / (outlet_segments-1);
+                
+                // Apply power function for curvature
+                r1 = outlet_throat_radius + (outlet_radius - outlet_throat_radius) * pow(t, outlet_curve_factor);
+                r2 = outlet_throat_radius + (outlet_radius - outlet_throat_radius) * pow((i+1) / (outlet_segments-1), outlet_curve_factor);
+
+                translate([0, 0, i * h])
+                cylinder(h = h, r1 = r1, r2 = r2, $fn = 75);
+            }
+        }
+
+        // Inner subtraction (to maintain thickness)
+        union() {
+            for (i = [0:outlet_segments-1]) {
+                h = outlet_length / outlet_segments;
+                t = i / (outlet_segments-1);
+                
+                r1 = (outlet_throat_radius + (outlet_radius - outlet_throat_radius) * pow(t, outlet_curve_factor)) - outlet_thickness;
+                r2 = (outlet_throat_radius + (outlet_radius - outlet_throat_radius) * pow((i+1) / (outlet_segments-1), outlet_curve_factor)) - outlet_thickness;
+
+                translate([0, 0, i * h])
+                cylinder(h = h, r1 = r1, r2 = r2, $fn = 75);
+            }
+        }
+
+        // Plate at the end of the outlet (sealed)
+        translate([0, 0, outlet_length])  // Align the plate to the end of the outlet
+        cylinder(h = outlet_thickness, r = outlet_radius, $fn = 75);  // Plate at the outlet (end)
+    }
+}
+
+// Rotate for correct orientation
+rotate([0, 90, 0]) outlet();
\ No newline at end of file