  In emergency egress crowd behavior critically affects egress efficiency and
public safety. By integrating psychological principles to Newtonian motion of
crowd, a fluid-based equation is derived in this paper to explore how energy in
different forms is balanced when pedestrian crowd pass through a bottleneck.
Such fluid-based analysis helps to bridge a gap among psychological findings,
pedestrian models and simulation results, and it further provides a new
perspective to understand how the faster-is-slower effect is caused and how
disastrous events (e.g., jamming and stampede) occur at a bottleneck passage.
