Nonuniform turbulent flow in rough beds flume
Abstract
The velocity and turbulence distributions of nonuniform flow (decelerating and accelerating flows) in rough beds flume were measured and investigated. It was found that: self similarity is preserved over the entire depth; Rotta's conditions for equilibrium flows are approximately attained; for decelerating flow, Coles' law can explain the mean velocity profiles very well over the entire depth, while for accelerating flow the validity of the law is more limited, i.e., only up to the point where the maximum velocity occurs; variation between pi and beta in open channel flow indicates a small difference with the one in pipe and in boundary layer flows; the turbulence intensities increase and decrease in decelerated and accelerated flows; as in pressure gradient boundary layer flow, the Reynolds stress distributions in open channel flow have convex forms for decelerating flow and concave ones for accelerating flow; the eddy and the mixing length distributions increase when the flow is decelerated, and decrease when it is accelerated; spectral measurements show that there is a region where the normalized energy spectral function is proportional to n exp 5/3, and the effect of pressure gradient to its distribution is practically not observed; and the macroscale and microscale values in decelerating flow are smaller than those in accelerating flow.
 Publication:

In its Activities Report of the Laboratory of Hydraulic Research 20 p (SEE N9222116 1334
 Pub Date:
 1990
 Bibcode:
 1990arlh.reptR....K
 Keywords:

 Flow Velocity;
 Nonuniform Flow;
 Reynolds Stress;
 Turbulent Flow;
 Velocity Distribution;
 Boundary Layer Flow;
 Equilibrium Flow;
 Flow Equations;
 Flow Visualization;
 Fluid Mechanics and Heat Transfer