Figure 4
From: Mechanical response of dense pedestrian crowds to the crossing of intruders
Average density field (top row, in ped/m2) and mean velocity field (bottom row) around the moving cylindrical intruder. The instructions given to the participants vary with the column: They were asked to behave casually (left, France, x9) or to refrain from any anticipation (middle, Argentina, x15) while facing the intruder in both cases, whereas on the rightmost column they were turning their backs to the intruder (right, Argentina, x10). The crowd’s density on the left column (\(\bar{\rho }\approx 3.5\) ped/m²) was slightly lower than in the other two columns (\(\bar{\rho }\approx 4.5\) ped/m²). Velocities are computed on the basis of the displacements performed over a time interval δt = 0.7s and the velocity scale is given by the red arrow, which represents a speed of 30 cm. s−1 [panel (d) is less magnified than panels (e,f)]. Note that panel (a) shows the same data as Fig. 2(b).
