Figure 7.

Sensitivity of the failure mode with respect to relative mucosal thickness for moderately elliptical cross-section with $R_{\mathrm{I}}:R_{\mathrm{II}}=1.5$. The instability occurs naturally at regions of highest curvature along the semi-major axis and propagates inward until it reaches the semi-minor axis. First contact occurs at regions of highest curvature and induces a moderately localized failure mode. This might indicate that airway obstruction is less drastic in moderately elliptical cross-sections than in circular cross-sections.