scripts/check_ic.py

import re, numpy as np

def read_foam_scalar(path):
    with open(path) as f:
        content = f.read()
    m = re.search(r'List<scalar>\s+(\d+)', content)
    if not m: return None, 0
    n = int(m.group(1))
    start = content.find('(', m.end()) + 1
    end = content.find(')', start)
    vals = np.array([float(x) for x in content[start:end].split()])
    return vals, n

cases = [
    ("rising_bubble", "t00", 128, 256, 1.0, 2.0),
    ("droplet_impact", "t00", 256, 256, 0.025, 0.025),
    ("dam_break", "t00", 128, 128, 0.584, 0.584),
]

for case, t, nx, ny, Lx, Ly in cases:
    path = f"/home/alanz/openfoam-workspace/output/data/{case}/{t}/0/alpha.water"
    vals, n = read_foam_scalar(path)
    if vals is None:
        print(f"{case}: FAILED to read")
        continue
    # OpenFOAM x-fastest: idx = i + j*nx, so reshape to (ny, nx)
    # np.where returns (row_idx, col_idx) = (y_idx, x_idx)
    arr = vals.reshape(ny, nx)

    if case == "rising_bubble":
        region = arr < 0.5  # bubble is alpha=0
        label = "bubble"
    elif case == "droplet_impact":
        region = arr > 0.5  # droplet is alpha=1
        label = "droplet"
    else:
        region = arr > 0.5  # water column is alpha=1
        label = "water"

    if region.sum() > 0:
        y_idx, x_idx = np.where(region)
        r_eq = np.sqrt(region.sum() / np.pi)
        dx = Lx / nx
        dy = Ly / ny
        # Cell center coordinates (0.5 offset for center of cell)
        cx_phys = (x_idx.mean() + 0.5) * dx
        cy_phys = (y_idx.mean() + 0.5) * dy
        r_phys = r_eq * dx  # isotropic: dx == dy for these cases
        print(f"{case}: {label}")
        print(f"  cells={region.sum()}, r_eq={r_eq:.1f} cells ({r_phys*1000:.2f}mm)")
        print(f"  center=({cx_phys*1000:.2f}mm, {cy_phys*1000:.2f}mm)")
        print(f"  domain={Lx*1000:.1f}x{Ly*1000:.1f}mm, dx=dy={dx*1000:.4f}mm")
        print(f"  x_cells=[{x_idx.min()},{x_idx.max()}], y_cells=[{y_idx.min()},{y_idx.max()}]")
        # Shape aspect ratio
        span_x = (x_idx.max() - x_idx.min() + 1)
        span_y = (y_idx.max() - y_idx.min() + 1)
        print(f"  span=({span_x},{span_y}) cells, aspect={span_x/span_y:.2f}")
    else:
        print(f"{case}: NO {label} region found")