Last update RocketPy-Team#801

caioessouza · caioessouza · commit 550e149fac7a · 2025-05-03T08:48:49.000-03:00
Corrected some minor code erros, like calling evaluate geometry before defining self.only_radial_burn. Also had to change the grain_height_derivative to zero in the case of only radial burn, it was leading to some physical incoherences, because the grain was still burning axially. The last tests to evaluate the physical behaviour went pretty well, so I'll open the PR.
diff --git a/rocketpy/motors/solid_motor.py b/rocketpy/motors/solid_motor.py
@@ -302,7 +302,7 @@ class Function. Thrust units are Newtons.
             "nozzle_to_combustion_chamber".
         only_radial_burn : boolean, optional
             If True, inhibits the grain from burning axially, only computing
-            radial burn. Otherwise, if False, allows the grain to also burn 
+            radial burn. Otherwise, if False, allows the grain to also burn
             axially. May be useful for axially inhibited grains or hybrid motors.
             Default is False.
 
@@ -343,10 +343,11 @@ class Function. Thrust units are Newtons.
         )
         self.grain_initial_mass = self.grain_density * self.grain_initial_volume
 
-        self.evaluate_geometry()
-
         # Burn surface definition
         self.only_radial_burn = only_radial_burn
+
+        self.evaluate_geometry()
+
         # Initialize plots and prints object
         self.prints = _SolidMotorPrints(self)
         self.plots = _SolidMotorPlots(self)
@@ -489,6 +490,10 @@ def geometry_dot(t, y):
             grain_inner_radius, grain_height = y
             if self.only_radial_burn:
                 burn_area = 2 * np.pi * (grain_inner_radius * grain_height)
+
+                grain_inner_radius_derivative = -volume_diff / burn_area
+                grain_height_derivative = 0
+
             else:
                 burn_area = (
                     2
@@ -500,8 +505,8 @@ def geometry_dot(t, y):
                     )
                 )
 
-            grain_inner_radius_derivative = -volume_diff / burn_area
-            grain_height_derivative = -2 * grain_inner_radius_derivative
+                grain_inner_radius_derivative = -volume_diff / burn_area
+                grain_height_derivative = -2 * grain_inner_radius_derivative
 
             return [grain_inner_radius_derivative, grain_height_derivative]
 
@@ -520,7 +525,7 @@ def geometry_jacobian(t, y):
                 inner_radius_derivative_wrt_inner_radius = factor * (
                     grain_height - 2 * grain_inner_radius
                 )
-                inner_radius_derivative_wrt_height = factor * grain_inner_radius
+                inner_radius_derivative_wrt_height = 0
                 height_derivative_wrt_inner_radius = 0
                 height_derivative_wrt_height = 0
 
