Hostname: page-component-78c5997874-8bhkd Total loading time: 0 Render date: 2024-11-05T08:45:19.575Z Has data issue: false hasContentIssue false

On some aspects of fully-developed turbulent flow in rectangular channels

Published online by Cambridge University Press:  28 March 2006

F. B. Gessner
Affiliation:
School of Mechanical Engineering, Purdue University Now at Virginia Polytechnic Institute, Blacksburg, Virginia.
J. B. Jones
Affiliation:
School of Mechanical Engineering, Purdue University Now at Virginia Polytechnic Institute, Blacksburg, Virginia.

Abstract

For fully-developed turbulent flow in straight channels of non-circular cross-section, there exists a transverse mean flow superimposed upon the axial mean flow. This transverse flow, commonly known as secondary flow, interacts with the axial mean flow and turbulence structure in a complex manner. In this paper several heretofore unexplored aspects of this type of secondary flow are discussed on the basis of results of an extensive experimental programme which was conducted for steady, incompressible, fully-developed turbulent air flow in both square and rectangular channels. Specifically, the following aspects are examined: (a) the Reynolds-number effect on secondary flow, (b) the directional characteristics of local wall shear stress, (c) the orientation of Reynolds-stress principal planes in a plane normal to the axial flow direction, and (d) the Reynolds equation along a secondary-flow streamline.

Within the Reynolds-number range of the investigation, the results indicate that secondary-flow velocities, when non-dimensionalized with either the bulk velocity or the axial mean-flow velocity at the channel centreline, decrease for an increase in Reynolds number. Also, the greatest skewness of local wall shear-stress vectors is shown to occur in the near vicinity of corners where secondary flow is maximum. In addition, it is shown that in planes normal to the axial flow direction, traces of Reynolds stress principal planes are not tangent and normal to lines of constant axial mean-flow velocity. This behaviour is in contrast to that for less complicated turbulent flows, for example, two-dimensional channel flow or circular-pipe flow where such traces are always tangent and normal to lines of constant axial mean-flow velocity in accordance with symmetry considerations. Finally, through experimental evaluation of terms in a momentum balance along a typical secondary-flow streamline, it is shown that secondary flow is the result of small differences in magnitude of opposing forces exerted by the Reynolds stresses and static pressure gradients in planes normal to the axial flow direction.

Type
Research Article
Copyright
© 1965 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

Brundrett, E. 1964 The production and diffusion of vorticity in duct flow. J. Fluid Mech. 19, 375.Google Scholar
Deissler, R. G. & Taylor, M. F. 1959 Analysis of turbulent flow and heat transfer in noncircular passages. NASA TR, no. R-31.Google Scholar
Gessner, F. B. 1964a Turbulence and mean-flow characteristics of fully-developed flow in rectangular channels. Doctoral thesis, Purdue University.
Gessner, F. B. 1964b A method of measuring Reynolds stresses with a constant-current, hot-wire anemometer. ASME Paper, 64-WA/FE-34.
Gessner, F. B. & Jones, J. B. 1961 A preliminary study of turbulence characteristics of flow along a corner. J. Basic Engng, Trans. ASME, 83, 657.Google Scholar
Gilbert, G. B. 1960 Secondary flow in straight rectangular ducts. Master's Thesis, Massachusetts Institute of Technology.
Hoagland, L. C. 1960 Fully-developed turbulent flow in straight rectangular ducts—secondary flow, its cause and effect on the primary flow. Doctoral Thesis, Massachusetts Institute of Technology.
Laufer, John 1951 Investigation of turbulent flow in a two-dimensional channel. NACA TR, no. 1053.Google Scholar
Leutheusser, H. J. 1963 Turbulent flow in rectangular ducts. J. Hyd. Div., Proc. ASCE, 89, 1.Google Scholar
Maslen, S. H. 1958 Transverse velocities in fully-developed flows. Quart. Appl. Math. 16, 173.Google Scholar
Moissis, R. 1957 Secondary flow in rectangular ducts. Master's Thesis, Massachusetts Institute of Technology.
Nikuradse, J. 1926 Untersuchungen über die Geschwindigkeitsverteilung in turbulenten Strömungen. V.D.I. Forschungsheft, 70, 1229.Google Scholar
Oman, R. A. 1959 The three-dimensional laminar boundary layer along a corner. Doctoral Thesis, Massachusetts Institute of Technology.
Rose, W. G. 1962 Symposium on Measurement in Unsteady Flow, pp. 859. ASME publication.
Townsend, A. A. 1956 The Structure of Turbulent Shear Flow. Cambridge University Press.