Average local velocity in the round pipe for fluid flow overclocking

摘要

The paper presents the results of experimental studies of the accelerating motion of a liquid in a cylindrical tube from a state of rest. Thermal anemometric equipment is used to determine the local characteristics of a non-stationary flow. It is established that with accelerated fluid motion from the state of rest to the appearance of turbulence, a uniform distribution of the velocities in the cross section of the pipe remains and only gradients of velocities are observed in a thin wall layer. At the moment of transition to the turbulent regime, a turning point appears on the graph of the change in the mean velocity, and the velocity distribution and the intensity of turbulence undergo significant changes in comparison with stationary turbulent flows. Turbulence is generated in the near-wall region and extends to the center of the pipeline section at practically constant speed