TITLE:
Decay of Pressure Fluctuation in the Hyporheic Zone around a Cylinder
AUTHORS:
Timothy Calappi, Carol Miller
KEYWORDS:
Hyporheic, Pressure, Cylinder, Scour
JOURNAL NAME:
World Journal of Mechanics,
Vol.6 No.4,
April
29,
2016
ABSTRACT: Erosion around a submerged cylinder is a well-studied problem, and is of
particular interest in bridge pier scour applications. Particles erode when
lift and drag forces overcome a critical threshold. These forces are typically studied
from above the water-riverbed interface and are related to geometry and
surficial processes. The present study maps hyporheic pressure fluctuations as
they are related to surface water velocity fluctuations. Relatively,
high-pressure events in the subsurface promote a destabilizing force from
within the riverbed and increase the potential for the mobilization of
sediment. Differential pressure transducers were fitted within a vertical
cylinder in a movable bed flume. The pressure ports were flush with the
cylinder surface and below the water-sand interface. The three-orthogonal
components of velocity were recorded synchronously with differential pressure
measured over a 15 mm depth. As expected, results show decay in pressure
fluctuations as a function of depth.