feat: AR-Shipdesign initial commit

arshipdesign/parametric/wizard_cruiser.py

@@ -23,6 +23,19 @@ from arshipdesign.core.hull import Hull
 from arshipdesign.core.offsets import OffsetsTable
 
 
+def _standard_sheer_z(
+    x_sta: np.ndarray, lpp: float, depth: float,
+    fwd_rise_frac: float = 0.055, aft_rise_frac: float = 0.025,
+) -> np.ndarray:
+    """Línea de cubierta parabólica: mínimo en cuaderna maestra, sube hacia proa/popa."""
+    xi = x_sta / lpp   # 0=AP, 1=FP, 0.5=midship
+    return np.where(
+        xi >= 0.5,
+        depth * (1.0 + fwd_rise_frac * ((xi - 0.5) / 0.5) ** 2),
+        depth * (1.0 + aft_rise_frac  * ((0.5 - xi) / 0.5) ** 2),
+    )
+
+
 # ---------------------------------------------------------------------------
 # Forma de sección — carena redonda tipo desplazamiento
 # ---------------------------------------------------------------------------
@@ -77,9 +90,10 @@ def make_displacement_hull(
     cm : float
         Coeficiente de cuaderna maestra (0.82–0.92).
     """
-    x_sta = np.linspace(0.0, lpp, n_stations)
-    z_wl  = np.linspace(0.0, draft, n_waterlines)
-    xi    = (x_sta / lpp - 0.5) * 2.0   # ∈ [−1, 1], 0=midship
+    x_sta   = np.linspace(0.0, lpp, n_stations)
+    sheer_z = _standard_sheer_z(x_sta, lpp, depth, fwd_rise_frac=0.055, aft_rise_frac=0.025)
+    z_wl    = np.linspace(0.0, float(sheer_z.max()), n_waterlines)
+    xi      = (x_sta / lpp - 0.5) * 2.0   # ∈ [−1, 1], 0=midship
 
     # ── Plan form (semi-manga en flotación) ────────────────────────────
     # LCB desplazado del midship
@@ -111,7 +125,8 @@ def make_displacement_hull(
         lpp=lpp, beam=beam, draft=draft,
     )
     return Hull(
-        name=name, lpp=lpp, beam=beam, depth=depth, draft=draft, offsets=offsets
+        name=name, lpp=lpp, beam=beam, depth=depth, draft=draft,
+        offsets=offsets, sheer_z=sheer_z,
     )