Experimental study and mathematical simulation of the characteristics of a turbulent flow in a straight circular pipe rotating about its longitudinal axis

Abstract

The vorticity formed in the cross section of a turbulent flow in a straight circular pipe rotating about its longitudinal azis decreases the values of the turbulent stresses, turbulence energy, and dissipation rate along the pipe. The results of laboratory ezperiments and calculations by the second-order closure model of turbulent transfer are presented. On the whole, the model using a system of transport equations yields better agreement with ezperimental data than the models with algebraic relations for second-order moments.Introduction. The action of mass forces in a swirling flow (centrifugal and Coriolis accelerations), which is similar to the action of the acceleration of gravity in a stratified flow [1, 2], weakens momentum and heat-transfer processes. The vorticity formed in the cross section of a turbulent flow in a straight circular pipe rotating about its longitudinal axis suppresses turbulent fluctuations and radial turbulent transfer at small and moderate velocities of pipe rotation: the turbulent stress, the turbulence energy, and its dissipation decrease.Onufriev and Khristianovich [3, 4] considered the influence of the swirling flow on its statistical characteristics on the basis of semi-empirical equations that describe the behavior of the mean velocity fields and the second-order moments in the local-equilibrium approximation.We present the data of laboratory measurements of the first-and second-order moments of the velocity field for a flow of an incompressible liquid in a motionless and rotating pipe. These data are compared with the calculation results obtained using three models of turbulent transfer. These models include differential transport equations for the components of the Reynolds stress tensor, algebraic relationships for normal turbulent stresses in the nonequilibrium approximation, and algebraic relationships for turbulent stresses in the local-equilibrium approximation, respectively.The experimental hot-wire anemometry results were obtained at the Moscow Physicotechnical Institute, and the calculations were performed at the Institute of Theoretical and Applied Mechanics of the Siberian Division of the Russian Academy of Sciences and Novosibirsk State University.Experimental Study of the Turbulent Flow Characteristics in a Rotating Pipe. The experiments were performed on a setup whose main units were the straight section of a channel whose length was equal to 100 diameters and which formed a developed turbulent flow and the rotating section, which was 25 diameters long (the channel diameter was 0.06 m). The air was injected into the channel from a high-pressure pipeline through a reductor and a flow governor, which ensured a constant flow rate. The temperature of the air injected into the channel was maintained constant and equal to room temperature by means of an automatically adjusted heater. After the heater, the air entered a receiver wherein it passed

Reynolds-stress and triple-product models applied to flows with rotation and curvature

“…The value of Re τ = uτ R νw is reported as 875, 18 and this was the Reynolds number matched for the bulk of these simulations. Room temperature was reported as 15 • C-18 • C, and for the present paper, 288.15K = 15 • C was used.…”

Optimization of Swirling Flow Energy Parameters on the Velocity Profile after Local Obstacle by Firefly Algorithm

“…Recently, researchers conducted simulations of these processes and obtained the results which were used as a platform for further upgrade in this field. Zaets et al (1998) performed experimental study and mathematical simulation of an axisymmetric turbulent flow in a straight circular pipe and gave a good theoretic base for development of mathematical models. In addition, the authors investigated distribution and dissipation of turbulence energy 2 0 ( / ) E u and distribution of velocity components, which was taken as a basis for this research.…”