Turbulent forces in supercritical flows in open channel

Abstract EN

A force measuring transducer was developed to isolate and measure (instantaneously and simultaneously) the hydrodynamic drag, lift and torque on a sphere suspended in a steep shallow stream.

Being an idealized model, it has improved the understanding of the mechanics of removal of a sphere from a bed of similar spheres.

Statistical analysis of the force measurements (on a very light sphere attached to the force transducer) showed that: drag generally increases with stream power and sphere protrusion, lift becomes predominantly negative in a shallow steep stream and torque due to the uneven distribution of skin friction stresses on the surface of the sphere is an equally significant contributor to the initial removal of a sphere as drag and lift.