Predeclare zero-damping pinball development cases

research/steady_pinball/run.py

@@ -1,6 +1,6 @@
 """Uncontrolled paper-geometry steady Re_D=50, one transverse assembly DOF.
 
-One fixed protocol; --smoke performs 32 warmup + 32 observation steps only.
+Three predeclared zero-damping structures; --smoke uses only 32 + 32 steps.
 See docs/steady_pinball_fiv.md for historical solver differences and new structure.
 """
 from __future__ import annotations
@@ -18,6 +18,7 @@ D, U, NU = 20., .01, .004
 CENTRES = ((600., 255.5), (626., 270.5), (626., 240.5))
 PROBES = ((800., 295.5), (800., 255.5), (800., 215.5))
 WARMUP, STEPS, PERIOD = 512000, 600000, 10000
+STRUCTURES = {'Z0': (10., 1.e-4), 'M2': (2., 1.e-4), 'R2': (2., 6.e-5)}
 COLUMNS = ('step', 'y', 'v', 'cme_F', 'cme_U', 'cme_L', 'wen_F', 'wen_U', 'wen_L',
            'node_F', 'node_U', 'node_L', 'eq_only', 'no_donor', 'crossings')
 ROOT = Path(__file__).resolve().parents[2]
@@ -29,10 +30,15 @@ def config():
 
 class Structure:
     """Exact damped oscillator update for a force held over dt=1; no force filter."""
-    def __init__(self):
-        self.mass = 10. * 3. * math.pi * D * D / 4.
-        self.omega = 2. * math.pi / PERIOD
-        self.zeta = .01
+    def __init__(self, mass_ratio=10., frequency=1.e-4, zeta=0.):
+        if not (math.isfinite(mass_ratio) and mass_ratio > 0. and
+                math.isfinite(frequency) and frequency > 0. and
+                math.isfinite(zeta) and 0. <= zeta < 1.):
+            raise ValueError('positive finite mass ratio/frequency and 0 <= zeta < 1 required')
+        self.mass_ratio, self.frequency = mass_ratio, frequency
+        self.mass = mass_ratio * 3. * math.pi * D * D / 4.
+        self.omega = 2. * math.pi * frequency
+        self.zeta = zeta
         self.stiffness = self.mass * self.omega**2
         self.damping = 2. * self.zeta * self.mass * self.omega
         self.y = self.v = 0.
@@ -68,6 +74,8 @@ def main():
     ap.add_argument('--out', required=True, type=Path)
     ap.add_argument('--fixed', action='store_true', help='same modern moving-path geometry held fixed')
     ap.add_argument('--smoke', action='store_true', help='32+32 steps, no physical result')
+    ap.add_argument('--case', choices=STRUCTURES, default='Z0',
+                    help='predeclared structure; all cases have zero structural damping')
     args = ap.parse_args()
     out = args.out.resolve()
     if out == ROOT or ROOT in out.parents:
@@ -76,7 +84,7 @@ def main():
     cfg = config()
     (out/'config.json').write_text(json.dumps(cfg, indent=2)+'\n')
     source = subprocess.check_output(['git', '-C', str(ROOT), 'rev-parse', 'HEAD'], text=True).strip()
-    s = Structure()
+    s = Structure(*STRUCTURES[args.case], zeta=0.)
     warmup, count = (32, 32) if args.smoke else (WARMUP, STEPS)
     rows = np.lib.format.open_memmap(out/'steps.npy', mode='w+', dtype=np.float64,
                                      shape=(count, len(COLUMNS)))
@@ -87,11 +95,13 @@ def main():
     col = {k: names.index(k) for k in names}
     status, completed, f_last = 'running', 0, 0.
     started = time.monotonic()
-    report = dict(source=source, fixed=args.fixed, smoke=args.smoke, columns=COLUMNS,
+    report = dict(source=source, case=args.case, fixed=args.fixed, smoke=args.smoke, columns=COLUMNS,
                   structure=dict(mass=s.mass, stiffness=s.stiffness, damping=s.damping,
-                                 zeta=s.zeta, fn=1./PERIOD, y0=0., v0=0.),
+                                 mass_ratio_three_disks=s.mass_ratio,
+                                 zeta=s.zeta, fn=s.frequency, Tn=1./s.frequency, y0=0., v0=0.),
                   warmup_steps=warmup, requested_steps=count, dt=1., D=D, U=U, nu=NU,
-                  duration_Tn=count/PERIOD, duration_tU_D=count*U/D,
+                  duration_Tn=count*s.frequency, duration_tU_D=count*U/D,
+                  summary_block_steps=10*PERIOD,
                   rhs='sum of three instantaneous CME_y + Wen_y, one-step lag, no filtering')
     try:
         with Simulation(str(out/'config.json')) as sim:
@@ -135,7 +145,7 @@ def main():
                 f_last = float(cme.sum(dtype=np.float64)+wen.sum(dtype=np.float64))
                 if completed % PERIOD == 0:
                     rows.flush()
-                    print(json.dumps(dict(event='period', step=completed, t_Tn=completed/PERIOD,
+                    print(json.dumps(dict(event='progress', step=completed, t_Tn=completed*s.frequency,
                                           y_D=s.y/D, elapsed_s=time.monotonic()-started)), flush=True)
             else:
                 status = 'smoke_completed' if args.smoke else 'duration_completed_not_qualified'