Fully developed periodic turbulent pipe flow. Part 1. Main experimental results and comparison with predictions

Abstract

The present paper is the first part of a two-part report on a detailed investigation of periodic turbulent pipe flow. In this investigation, experimental data on instantaneous velocity and wall shear stress were obtained at a mean Reynolds number of 50000 in a fully developed turbulent pipe flow in which the volumetric flow rate was varied sinusoidally with time around the mean. Two oscillation frequencies at significant levels of flow modulation were studied in detail. The higher of these frequencies was of the order of the turbulent bursting frequency in the flow, and the other can be regarded as an intermediate frequency at which the flow still departed significantly from quasi-steady behaviour. While a few similar experiments have been reported in the recent literature, the present study stands out from the others in respect of the flow regimes investigated, the magnitude of flow modulation, the detailed nature of the measurements and most importantly the identification of a relevant parameter to characterize unsteady shear flows. The present paper contains the main experimental results and comparisons of these results with the results of a numerical calculation procedure which employs a well-known quasi-steady turbulence closure model. The experimental data are used to study the manner in which the time-mean, the ensemble-averaged and the random flow properties are influenced by flow oscillation at moderate to high frequencies. In addition, the data are also used to bring out the capability and limitations of quasi-steady turbulence modelling in the prediction of unsteady shear flows. A further and more detailed analysis of the experimental data, results of some additional experiments and a discussion on the characterization of turbulent shear flows are provided in Part 2 (Ramaprian & Tu 1983).

Numerical analysis of heat transfer in pulsating turbulent flow in a pipe

“…Since experimental data in pulsating turbulent flow with large oscillating velocity amplitudes is lacking, experimental results obtained by Tu and Ramaprian [5] are used as the comparison data. Tu and Ramaprian experimentally measured the sectional velocity distribution in the fully developed pulsating turbulent flow of water, in which the Reynolds number was Re = 50,000 and the Womersley number was Wo = 118.5.…”

“…Experimental studies on pulsating turbulent flow were conducted actively [1][2][3][4][5][6][7][8][9][10]. All of the measurements were made for fully developed flows with small oscillating velocity amplitudes.…”

Extension of the momentum transfer model to time-dependent pipe turbulence

“…The Vardy-Brown weighting function has two adjustable parameters, the A and C constants eqs. (18) and (19). Our model already has one parameter over and above the steady state model, namely the constant λ in eq.…”

“…The subject matter of time dependent turbulent pipe flows has considerable interest, both theoretical and practical [17][18][19][20][21]. The basic framework of analysis depends upon the separation of the flow velocity and pressure into a mean component and a turbulent fluctuation.…”

Transport Phenomena of Solid Particles in Pulsatile Pipe Flow

“…We first review studies of single-phase pulsating pipe flows. Early studies of turbulent pulsating pipe flows were reported by Ramaprian and Tu [9][10][11]. They used a single-component laser-Doppler-anemometry system to measure the local instantaneous velocity in a pipe with an internal diameter of 50 mm and a Reynolds number of 50000.…”