{
  "case": "cfd/stokes / Stokes drag on a sphere, F = 6*pi*mu*R*U",
  "citation": "Stokes, G.G. (1851), exact unbounded-domain creeping-flow drag law",
  "geometry": {
    "R_m": 0.01
  },
  "material": {
    "mu_Pa_s": 0.001,
    "rho_kg_m3": 1000.0
  },
  "U_m_s": 0.01,
  "note": "Domain-size sweep at a fixed, independently-validated sphere refinement level (surface_sizes=0.05*R). Pass requires the largest-domain error vs. the cited UNBOUNDED formula to be under 10.0% AND monotonically decreasing across the sweep -- demonstrated convergence to the cited value, not an assumed one.",
  "levels": [
    {
      "L_over_R": 6.0,
      "size_max_over_R": 0.8,
      "n_nodes": 69162,
      "sphere_tag": 7,
      "sphere_elements": 7046,
      "F_on_sphere_xyz_N": [
        2.48904750495048e-06,
        7.188332082405818e-09,
        7.24727970457619e-09
      ],
      "F_drag_x_N": 2.48904750495048e-06,
      "lateral_force_fraction_pct": 0.4101008144267745,
      "drag_error_pct_vs_unbounded": 32.04807133447257,
      "elapsed_s": 30.21950888633728
    },
    {
      "L_over_R": 12.0,
      "size_max_over_R": 1.6,
      "n_nodes": 68871,
      "sphere_tag": 7,
      "sphere_elements": 7002,
      "F_on_sphere_xyz_N": [
        2.15211590068322e-06,
        5.408428061789023e-10,
        6.931918946458447e-10
      ],
      "F_drag_x_N": 2.15211590068322e-06,
      "lateral_force_fraction_pct": 0.0408536984159405,
      "drag_error_pct_vs_unbounded": 14.17329456680031,
      "elapsed_s": 24.782994747161865
    },
    {
      "L_over_R": 20.0,
      "size_max_over_R": 2.666666666666667,
      "n_nodes": 69099,
      "sphere_tag": 7,
      "sphere_elements": 6940,
      "F_on_sphere_xyz_N": [
        2.0497432469746457e-06,
        1.1138822978475137e-08,
        3.864773116943451e-09
      ],
      "F_drag_x_N": 2.0497432469746457e-06,
      "lateral_force_fraction_pct": 0.575205885218027,
      "drag_error_pct_vs_unbounded": 8.742256608415493,
      "elapsed_s": 51.69665265083313
    },
    {
      "L_over_R": 30.0,
      "size_max_over_R": 4.0,
      "n_nodes": 68871,
      "sphere_tag": 7,
      "sphere_elements": 6910,
      "F_on_sphere_xyz_N": [
        1.997828822761161e-06,
        1.613650001012231e-08,
        7.692929916872793e-09
      ],
      "F_drag_x_N": 1.997828822761161e-06,
      "lateral_force_fraction_pct": 0.8947943522053812,
      "drag_error_pct_vs_unbounded": 5.988110864633609,
      "elapsed_s": 89.32818675041199
    }
  ],
  "drag_error_pct_by_level": [
    32.04807133447257,
    14.17329456680031,
    8.742256608415493,
    5.988110864633609
  ],
  "converging_to_unbounded": true,
  "F_exact_unbounded_N": 1.884955592153876e-06,
  "drag_error_pct_at_largest_domain": 5.988110864633609,
  "lateral_force_fraction_pct_at_largest_domain": 0.8947943522053812,
  "crosscheck_solver_agreement_pct": 0.010449867955159956,
  "solver_independent": true,
  "pass": true
}