Hostname: page-component-78c5997874-4rdpn Total loading time: 0 Render date: 2024-11-16T15:02:42.317Z Has data issue: false hasContentIssue false

On an analytical explanation of the phenomena observed in accelerated turbulent pipe flow

Published online by Cambridge University Press:  24 October 2019

F. Javier García García*
Affiliation:
Department of Naval and Industrial Engineering, Higher Polytechnic School, University of A Coruña, Campus de Esteiro, C/Mendizábal s/n, 15403 Ferrol, Spain Integraciones Técnicas de Seguridad, S.A., C/Nobel 15, 15650 Cambre, A Coruña, Spain
Pablo Fariñas Alvariño
Affiliation:
Department of Naval and Industrial Engineering, Higher Polytechnic School, University of A Coruña, Campus de Esteiro, C/Mendizábal s/n, 15403 Ferrol, Spain
*
Email address for correspondence: [email protected]

Abstract

This research presents a new theory that explains analytically the behaviour of any fully developed incompressible turbulent pipe flow, steady or unsteady. We propose the name of theory of underlying laminar flow (TULF), because its main consequence is the description of any turbulent pipe flow as the sum of two components: the underlying laminar flow (ULF) and the purely turbulent component (PTC). We use the framework of the TULF to explain analytically most of the important and interesting phenomena reported in He & Jackson (J. Fluid Mech., vol. 408, 2000, pp. 1–38). To do so, we develop a simple model for the pressure gradient and Reynolds shear stress that could be applied to the linearly accelerated pipe flow described by He & Jackson (2000). The following features of the unsteady flow are explained: the deformation undergone by the mean velocity profiles during the transient, the velocity overshoot observed in the more rapid excursions, the dual deformation of mean velocity profiles when overshoots are present, the laminarisation effects described during acceleration, the rapid decrease of the Reynolds shear stress upon approaching the wall that brings forth the laminar sublayer, and some other minor effects. A new field is defined to characterise the degree of turbulence within the flow, directly calculable from the theory itself. Arguably, this new field would describe the degree of turbulence in a pipe flow more accurately than the familiar turbulence intensity parameter. Finally, a paradox is found in the deformation of the unsteady mean velocity profiles with respect to equal-Reynolds-number steady profiles, which is duly explained. The research also predicts the occurrence of mean velocity undershoots if the flow is decreased rapidly enough.

Type
JFM Papers
Copyright
© 2019 Cambridge University Press 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Abramowitz, M. & Stegun, I. A.(Eds) 1972 Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables, Applied Mathematics Series, vol. 55. National Bureau of Standards.Google Scholar
Blackwelder, R. F. & Kovasznay, L. S. G. 1972 Large-scale motion of a turbulent boundary layer during relaminarization. J. Fluid Mech. 53 (1), 6183.Google Scholar
Carnap, R. 1966 Philosophical Foundations of Physics. Basic Books.Google Scholar
García García, F. J.2017 Transient discharge of a pressurised incompressible fluid through a pipe and analytical solution for unsteady turbulent pipe flow. PhD thesis, Higher Polytechnic School – University of A Coruña http://hdl.handle.net/2183/18502.Google Scholar
García García, F. J. & Fariñas Alvariño, P. 2019 On an analytic solution for general unsteady/transient turbulent pipe flow and starting turbulent flow. Eur. J. Mech. (B/Fluids) 74, 200210.Google Scholar
Gloss, D. & Herwig, H. 2010 Wall roughness effects in laminar flows: an often ignored though significant issue. Exp. Fluids 49, 461470.Google Scholar
Greenblatt, D. & Moss, E. A. 1999 Pipe-flow relaminarization by temporal acceleration. Phys. Fluids 11 (11), 34783481.Google Scholar
He, S.1992 On transient turbulent pipe flow. PhD thesis, University of Manchester.Google Scholar
He, S. & Jackson, J. D. 2000 A study of turbulence under conditions of transient flow in a pipe. J. Fluid Mech. 408, 138.Google Scholar
He, S. & Seddighi, M. 2015 Transition of transient channel flow after a change in Reynolds number. J. Fluid Mech. 764, 395427.Google Scholar
Jung, S. Y. & Chung, Y. M. 2012 Large-eddy simulation of accelerated turbulent flow in a circular pipe. Intl J. Heat Fluid Flow 33, 18.Google Scholar
Narasimha, R. & Sreenivasan, K. R. 1973 Relaminarization in highly accelerated turbulent boundary layers. J. Fluid Mech. 61 (3), 417447.Google Scholar
Narasimha, R. & Sreenivasan, K. R. 1979 Relaminarization of fluid flows. Adv. Appl. Mech. 19, 221309.Google Scholar
Pai, S. I. 1953 On turbulent flow in a circular pipe. J. Franklin Inst. 256 (4), 337352.Google Scholar
Prudnikov, A. P., Brychkov, Y. A. & Marichev, O. I. 1986 Integrals and Series. Volume 2. Special Functions. Gordon and Breach.Google Scholar
Sreenivasan, K. R. 1982 Laminarescent, relaminarizing and retransitional flows. Acta Mechanica 44, 148.Google Scholar
White, F. M. 2006 Viscous Fluid Flow, 3rd edn. McGraw-Hill.Google Scholar
Zagarola, M. V.1998 Princeton Superpipe data. Available at: http://www.princeton.edu/gasdyn/index.html#superpipe_data.Google Scholar