  Homogeneous and isotropic turbulent fields obtained from two DNS databases
(with $\mbox{Re}_\lambda$ equal to 150 and 418) were seeded with point
particles that moved with the local fluid velocity to obtain Lagrangian
pressure histories. Motivated by cavitation inception modeling, the statistics
of events in which such particles undergo low-pressure fluctuations were
computed, parameterized by the amplitude of the fluctuations and by their
duration. The main results are the average frequencies of these events and the
probabilistic distribution of their duration, which are of predictive value. A
connection is also established between these average frequencies and the
pressure probability density function, thus justifying experimental methods
proposed in the literature. Further analyses of the data show that the
occurrence of very-low-pressure events is highly intermittent and is associated
with worm-like vortical structures of length comparable to the integral scale
of the flow.
