EFFECT OF ECCENTRICITY ON THE PRESSURE AND VELOCITY GRADIENTS ALONG A STREAMLINE PAST A CYLINDERICAL BODY

  • Ali A. Jazie Al-Khaledy College of engineering\ Al-Qadisiya University
Keywords: viscous flow, aspect ratio, boundary layer separation, wake, bluff body

Abstract

In chemical technology and power engineering, equipment containing heat exchanging pipes and various cylindrical links immersed into moving fluid was often used. The estimation of the hydrodynamic action on these elements is based on the solution of the plane problem on the flow past a cylinder. In the hydrodynamics of inviscid flow past a body of nonzero thickness, it was assumed that there are regions near the body in which the flow accelerates from the front stagnation point to the midsection and decelerates behind the midsection. According to the Bernoulli theorem, a pressure counter-gradient arises in the deceleration region, which acts both in the outer flow and in the boundary layer. For the inviscid flow, the fluid particles store sufficiently much kinetic energy in the acceleration region to overcome this barrier, but in the frictional flow, the fluidparticles that remain in the boundary layer cannot reach the region of higher pressure. They are pushed away from the wall, and an opposite flow arises downstream. This phenomenon is known as the boundary layer separation. A CFD models were simulated for the viscous flow past bodies changed from a circular cylinder to flat plate. FLUENT 6.3.26 package was used for solving the model preprocessed in GAMBIT 2.3.16 for flow past a body. Fluent solvers were based on the finite volume method and general conservation (transport) equation for momentum was discretized into algebraic equations. The pressure and velocity gradients for viscous flow past bodies changed from a circular cylinder to flat plate was predicted and plotted and the effect of eccentricity on the pressure and velocity gradients was studied.

References

[1 M. Coutanceau, R. Bouard, Experimental determination of the main features of the viscous flow
in the wake of a circular cylinder in uniform translation. Part 1, steady flow, J. Fluid Mech. 79 (Pt.
2) (1977) 231–256.
D. Li, The small flow becomes main stream, Microfluidics Nanofluidics1 (1) (2004)1.
V. Streeter, Handbook of Fluid Dynamics, McGraw-Hill, New York, 1961.
H. Schlichting, Boundary-Layer Theory, McGraw-Hill, New York, 1979.
S. Taneda, Experimental investigation of the wakes behind cylinders and plates at low Reynolds
numbers, J. Phys. Soc. Jpn. 11 (3) (1956) 303–307.
S. Taneda, Standing Twin-Vortices Behind a Thin Flat Plate Normal to the Flow, Reports of
Research Institute for Applied Mechanics, Kyushu University, vol. 54, 1968, pp. 155–163.
S. Dennis, G. Chang, Numerical solutions for steady flow past a circular cylinder at Reynolds
numbers up to 100, J. Fluid Mech. 42 (Pt. 3) (1970) 471–489.
F. Nieuwstadt, H.B. Keller, Viscous flow past circular cylinders, Comput. Fluids 1 (1973) 59–71.
M. Van Dyke, An Album of Fluid Motion, Parabolic Press, Stanford, 1982.
K. Shintani, A. Umemura, A. Takano, Low-Reynolds-number flow past an elliptic cylinder, J.
Fluid Mech. 136 (1983) 277–289.
Y. Nakayama, W.A. Woods, D.G. Clark, Visualized Flow: Fluid Motion in Basic and Engineering
Situations Revealed by Flow Visualization, Pergamon, Oxford, 1988.
R.M. Wu, D.J. Lee, Hydrodynamic drag on non-spherical floc and free-settling test, Water Res. 35
(13) (2001) 3226–3234.
H. J. Lugt and H. J. Haussling, Naval Ship Research and Development Center Report 3748, Dept.
of Navy, 1972 (unpublished).
H. J. Lugt and H. J. Haussling, J. Fluid Mech. 65(4), 771 (1974).
K. E. J. Blodgett, M.S. thesis, Department of Aerospace Engineering and Engineering Mechanics,
University of Cincinnati, 1989 (unpublished).
C. Canuto, M. Y. Hussaini, A. Quarteroni, and T. A. Zang, Spectral Methods in Fluid Dynamics
(Springer-Verlag, New York, 1988).
A. T. Patera, J. Comput. Phys. 54, 468 (1984).
C. L. Street, and M. Macaraeg, Appl. Numer. Math. 6, 123 (1989).
M. Zdravkovich, Flow Around Circular Cylinders, vol. 1, Oxford Science Publication, 1997.
Chen S-S. Flow-induced vibration of circular cylindrical structures. Springer Verlag; 1987.
B.N. Rajani , A. Kandasamy , Sekhar M., Flow separation behind ellipses at Reynolds numbers
less than 10, Applied Mathematical Modelling, 33 (2009) 1228–1247.
David S., Hector R. Bravo, Numerical simulation of laminar flow past a circular cylinder, Applied
Mathematical Modelling, 33 (2009) 1633–1643.
Antoine P., J. Sigrist , Aziz H., Numerical simulation of an oscillating cylinder in a cross-flow at
low Reynolds number: Forced and free oscillations, Computers & Fluids, 38 (2009) ,80–100.
Williamson C-H-K. Advances in our understanding of vortex dynamics in bluff body wakes. J
Wind Eng Ind Aerodyn 1997:3–32.
Ferziger J-H, Peric´ M. Computational methods for fluid dynamics. Springer Verlag; 1996.
FLUENT Flow Modeling Software, Fluent Inc., Lebanon, NH, 2007.
C. Norberg, Pressure forces on a circular cylinder in cross flow, Springer-Verlag, Berlin, 1993, pp.
275–278.
Published
2017-07-18
How to Cite
A. Jazie Al-Khaledy, A. (2017). EFFECT OF ECCENTRICITY ON THE PRESSURE AND VELOCITY GRADIENTS ALONG A STREAMLINE PAST A CYLINDERICAL BODY. Al-Qadisiyah Journal for Engineering Sciences, 2(2), 459-476. Retrieved from http://qu.edu.iq/journaleng/index.php/JQES/article/view/76
Section
Articles