Figure 6.

Pressure drop coefficient (C_p; left) and particle residence time distributions (right) are shown for (a) subject A and (b) subject B. C_p was calculated using the average area-weighted total pressure across slices extracted through each volume mesh, and for different inflow boundary profiles (circles, flat; squares, pipe inflow; triangles, face; the slice locations are depicted in figures 1 and 8). The distances between successive area-centroids (X) are plotted against pressure coefficient, which is normalized by the dynamic pressure at the nasal valve (C_p = ΔP/½ρŪ²). Posterior to the nasal valve the pressure curves for all configurations drop in unison, though deviations are more noticeable for subject B; the pressure drop curves, through the passageway of subject A, are nearly identical when comparing the pipe inflow and face configurations. Probability mass functions (PMFs) are used to depict the residence time (t*, normalized by mean residence times shown in table 4) distributions of 40 000 passive particles tracked through the computational domain. The convergence of residence time distributions is depicted for subject A using a flat profile; the inset plot represents the profile for clouds of 40 000 and 20 000 particles (left and right bars, respectively). Blue bars, flat; red bars, pipe inflow; black bars, face.