import numpy as np
import matplotlib.pyplot as plt
from pygasflow.atd import viscosity_chapman_enskog
T = np.linspace(200, 1000)
gases = ['air', 'N2', 'O2', 'NO', 'N', 'O', 'Ar', 'He']
fig, ax = plt.subplots()
for gas in gases:
    ax.plot(T, viscosity_chapman_enskog(T, gas=gas), label=gas)
ax.legend()
ax.set_xlabel("Temperature [K]")
ax.set_ylabel("Viscosity [kg / (m * s)]")
plt.show()