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Effects of an axisymmetric contraction on a turbulent pipe flow

Published online by Cambridge University Press:  12 October 2011

Seong Jae Jang
Affiliation:
Department of Mechanical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Korea
Hyung Jin Sung*
Affiliation:
Department of Mechanical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Korea
Per-Åge Krogstad
Affiliation:
Department of Energy and Process Engineering, Norwegian University of Science and Technology, N-7491, Trondheim, Norway
*
Email address for correspondence: [email protected]

Abstract

The flow in an axisymmetric contraction fitted to a fully developed pipe flow is experimentally and numerically studied. The reduction in turbulence intensity in the core region of the flow is discussed on the basis of the budgets for the various turbulent stresses as they develop downstream. The contraction generates a corresponding increase in energy in the near-wall region, where the sources for energy production are quite different and of opposite sign compared to the core region, where these effects are caused primarily by vortex stretching. The vortices in the pipe become aligned with the flow as the stretching develops through the contraction. Vortices which originally have a spanwise component in the pipe are stretched into pairs of counter-rotating vortices which become disconnected and aligned with the mean flow. The structures originating in the pipe which are inclined at an angle with respect to the wall are rotated towards the local mean streamlines. In the very near-wall region and the central part of the contraction the flow tends towards two-component turbulence, but these structures are different. The streamwise and azimuthal stresses are dominant in the near-wall region, while the lateral components dominate in the central part of the flow. The two regions are separated by a rather thin region where the flow is almost isotropic.

Type
Papers
Copyright
Copyright © Cambridge University Press 2011

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References

1. Adrian, R. J., Jones, B. G., Chung, M. K., Hassan, Y., Nithianandan, C. K. & Tung, A. T. C. 1989 Approximation of turbulent conditional averages by stochastic estimation. Phys. Fluids A 1, 992998.CrossRefGoogle Scholar
2. Afzal, N. & Narasimha, R. 1976 Axisymmetric turbulent boundary layer along a circular cylinder at constant pressure. J. Fluid Mech. 74, 113128.Google Scholar
3. Akselvoll, K. & Moin, P. 1995. Report no. TF-63, Thermosciences Division, Department of Mechanical Engineering, Stanford University.Google Scholar
4. Bakken, O. M. & Krogstad, P.-Å 2004 A velocity dependent effective angle method for calibration of X-probes at low velocities. Exp. Fluids 37, 146152.CrossRefGoogle Scholar
5. Batchelor, G. K. 1953 The Theory of Homogeneous Turbulence. Cambridge University Press.Google Scholar
6. Cal, R. B. & Castillo, L. 2008 Similarity analysis of favourable pressure gradient turbulent boundary layers with eventual quasilaminarization. Phys. Fluids 20, 105106.CrossRefGoogle Scholar
7. Choi, H., Moin, P. & Kim, J. 1993 Direct numerical simulation of turbulent flow over riblets. J. Fluid Mech. 255, 503539.CrossRefGoogle Scholar
8. Comte-Bellot, G. & Corrsin, S. 1966 The use of a contraction to improve the isotropy of grid-generated turbulence. J. Fluid Mech. 25, 657682.CrossRefGoogle Scholar
9. Davis, R. T., Whitehead, R. E. & Wornom, S. F. 1971 The development of an incompressible boundary-layer theory valid to second order. Heat Mass Transfer. 4, 167177.Google Scholar
10. Durst, F., Jovanović, J. & Sender, J. 1995 LDA measurements in the near-wall region of a turbulent pipe flow. J. Fluid Mech. 295, 305335.CrossRefGoogle Scholar
11. Ertunç, Ö. & Durst, F. 2008 On the high contraction ratio anomaly of axisymmetric contraction of grid-generated turbulence. Phys. Fluids 20, 025103.Google Scholar
12. Hussain, A. K. M. F. & Ramjee, V. 1976 Effects of the axisymmetric contraction shape on incompressible turbulent flow. Trans. ASME: J. Fluids Engng 98, 5869.Google Scholar
13. Kim, K., Baek, S. J. & Sung, H. J. 2002 An implicit velocity decoupling procedure for the incompressible Navier–Stokes equations. Intl J. Numer. Meth. Fluids 38, 125138.CrossRefGoogle Scholar
14. Lee, M. & Reynolds, W. 1985 Numerical experiments on the structure of homogeneous turbulence. Rep. TF-24, Thermoscience Division, Stanford University.CrossRefGoogle Scholar
15. Lumley, J. L. & Newman, G. R. 1977 The return to isotropy of homogeneous turbulence. J. Fluid Mech. 82, 161178.CrossRefGoogle Scholar
16. Moin, P., Adrian, R. J. & Kim, J. 1987 Stochastic estimation of organized structures in turbulent channel flow. In Sixth Symposium on Turbulent Shear Flows, Toulouse, France, pp. 16.9.1–16.9.8.Google Scholar
17. Nawrath, S. J., Khan, M. M. K. & Welsh, M. C. 2006 An experimental study of scale growth rate and flow velocity of a super-saturated caustic–aluminate solution. Intl J. Miner. Process. 80, 116215.CrossRefGoogle Scholar
18. Pope, S. B. 2000 Turbulent Flows. Cambridge University Press.CrossRefGoogle Scholar
19. Prandtl, L. 1933 Attaining a steady air stream in wind tunnels. NACA Tech. Mem. 726.Google Scholar
20. Robinson, S. K. 1991 Coherent motions in the turbulent boundary layer. Annu. Rev. Fluid Mech. 23, 601639.CrossRefGoogle Scholar
21. Savill, A. M. 1987 Recent developments in rapid-distortion theory. Annu. Rev. Fluid Mech. 19, 531575.CrossRefGoogle Scholar
22. Spekreijse, S. P. 1995 Elliptic grid generation based on Laplace equations and algebraic transformation. J. Comput. Phys 118, 3861.CrossRefGoogle Scholar
23. Sreenivasan, K. R. & Narasimha, R. 1978 Rapid distortion of axisymmetric turbulence. J. Fluid Mech. 84, 497516.CrossRefGoogle Scholar
24. Taylor, G. I. 1935 Turbulence in a contracting stream. Z. Angew. Math. Mech. 15, 9196.CrossRefGoogle Scholar
25. den Toonder, J. M. J. & Nieuwstadt, F. T. M. 1997 Reynolds number effects in a turbulent pipe flow for low to moderate Re. Phys. Fluids 9, 33983409.CrossRefGoogle Scholar
26. Uberoi, M. S. 1956 Effect of wind-tunnel contraction on free stream turbulence. J. Aero. Sci. 23, 754764.CrossRefGoogle Scholar
27. Uberoi, M. S. & Wallis, S. 1966 Small axisymmetric contraction of grid turbulence. J. Fluid Mech. 24, 539543.CrossRefGoogle Scholar
28. Wu, X. & Moin, P. 2008 A direct numerical simulation study on the mean velocity characteristics in turbulent pipe flow. J. Fluid Mech. 608, 81112.CrossRefGoogle Scholar
29. Zhou, J., Adrian, R. J., Balachandar, S. & Kendall, T. M. 1999 Mechanisms for generating coherent packets of hairpin vortices in channel flow. J. Fluid Mech. 387, 353396.CrossRefGoogle Scholar