Darcy friction across two flow regimes

Compute an inspectable engineering model using SI inputs. See the linked domain guide for assumptions and benchmark checks.

import matplotlib.pyplot as plt
import numpy as np

from engineeringkit.fluid_engineering import colebrook_friction_factor

fig, ax = plt.subplots()
for roughness in [0, 1e-4, 0.01]:
    for lower, upper in [(100, 2299), (4000, 1e7)]:
        re = np.logspace(np.log10(lower), np.log10(upper), 100)
        factors = [colebrook_friction_factor(value, roughness) for value in re]
        label = f"relative roughness={roughness}" if lower == 4000 else None
        ax.loglog(re, factors, label=label)
ax.axvspan(2300, 4000, color="gray", alpha=0.2, label="transition excluded")
ax.set(xlabel="Reynolds number", ylabel="Darcy friction factor")
ax.legend()

plt.show()