A wide river flows steadily toward the east with uniform speed
PHYSICS · Multi-part · CBSE · Physics · Mechanical Properties of Fluids · Mechanical Properties of Fluids
Problem
A wide river flows steadily toward the east with uniform speed vflow=1.2ms−1. At a particular location, a pressure probe is mounted so that its sensing face is always oriented vertically upward. The probe can be raised or lowered to different depths. Engineers want to know whether the flowing motion of the river affects the pressure–vs.–depth relationship compared with the same river water when it is perfectly still.
(a) When the probe is held at a depth of 2.0m below the surface, it registers a pressure that is essentially identical to the pressure measured at the same depth in a nearby, stagnant pond. Explain qualitatively, using molecular considerations, why the horizontal flow does not significantly alter the hydrostatic pressure at that depth.
(b) Under what fluid conditions (if any) would you expect the pressure at a given depth in a moving liquid to deviate measurably from the pressure in the same liquid at rest? Provide a conceptual explanation rooted in particle motion and momentum transfer.