Abstract
The present experimental investigation deals with the behaviour of a wake generated by a square cylinder developing in a curved diffuser, a curved duct, a straight duct and a straight diffuser having a same pressure gradient as in the curved diffuser. This enables a systematic study of the effects of curvature and pressure gradient on wake development. It is seen that the curvature makes the wake asymmetric; the wake half width increases on the inner side and decreases on the outer side; the inner side being the region between the centreline and the wall closer to the centre of curvature and the outer side being the region between the centreline and the other wall. It causes a higher entrainment in the inner side as compared to the outer side. An adverse pressure gradient, on the other hand, causes a higher wake growth and velocity defect but reduces the rate of decay of the velocity defect. These are not altered significantly when the curvature and pressure gradient effects are combined. The curvature enhances the Reynolds stresses and the kinetic energy on the inner side and suppresses them on the outer side which makes their profiles asymmetric. These profiles become more and more asymmetric with increase in the streamwise distance. When the effects of curvature and adverse pressure gradient are combined, the profiles become further asymmetric.
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References
Balabaskaran V; Tulapurkara EG; Ravisundar T (1994) Effect of fins on secondary flow in curved square ducts. Submitted to the Sixth Asian Congress of Fluid Mechanics to be held at Singapore during May 22–26, 1995
Baskaran V; Smits AJ; Joubert PN (1987) A turbulent flow over a curved hill. Part 1. Growth of an internal boundary layer. J Fluid Mech 182: 47–83
Baskaran V; Smits AJ; Joubert PN (1991) A turbulent flow over a curved hill. Part 2. Effects of streamline curvature and streamwise pressure gradient. J Fluid Mech 232: 377–402
Bradshaw P (1973) Effects of streamline curvature on turbulent Flow. AGARDograph No. 169
Castro IP; Bradshaw P (1976) The turbulence structure of a highly curved mixing layer. J Fluid Mech 73: 265–304
Fox RW; Kline SJ (1962) Flow regimes in curved subsonic diffusers. Trans ASME J of Basic Eng 84: 303–312
Hill PG; Schaub UW; Senoo Y (1963) Turbulent wakes in pressure gradients. Trans ASME E: J Appl Mech 30: 518–524
Hoffman PH; Muck KC; Bradshaw P (1985) The effect of concave surface curvature on turbulent boundary layer. J Fluid Mech 161: 371–403
Johnson AE; Hancock PE (1991) The effect of extra strain rates of streamline curvature and divergence on mixing layers. Turbulent Shear Flows 7 (F Durst, BE Launder, WC Reynolds, FW Schmidt, JH Whitelaw (eds)). pp 253–267. Springer, Berlin, Heidelberg
Lemonnier PE; Garem JH; Tsen LF (1974) Sillage turbulent créé par une plaque plane en écoulement fortement décéléré. Centre D'etudes Aerodynamiques Et Thermiques, Poitiers, France, Contrat D.R.M.E n∘ 73.765, 2e rapport semestriel
Masuda W; Andoh S (1989) Effects of curvature on the initial mixing region of a two-dimensional jet. AIAA J 27: 52–56
Muck KC; Hoffman PH; Bradshaw P (1985) The effect of convex surface curvature on turbulent boundary layer. J Fluid Mech 161: 347–369
Nakayama A (1987) Curvature and pressure-gradient effects on a small defect wake. J Fluid Mech 175: 215–246
Narasimhan JL; Ramjee V; Diwakar PM; Tulapurkara EG (1991) Prediction of wake in a curved duct. Int J Num Methods Fluids 13: 907–916
Plesniak MW; Johnston JP (1989) Reynolds stress evolution in curved two-stream mixing layers. Proceedings of the Seventh Symposium on Turbulent Shear Flows, Stanford University, Aug 21–23, 6.3.1.–6.3.6
Ramaprian BR; Shivprasad BG (1978) The structure of turbulent boundary layers along mildly curved surfaces. J Fluid Mech 85: 273–303
Ramjee V; Tulapurkara EG; Rajasekar R (1988) Development of airfoil wake in a longitudinally curved stream. AIAA J 26: 948–953
Ramjee V; Neelakandan D (1989) Development of wake of a rectangular cylinder in a curved stream. Exp Fluids 7: 395–399
Ramjee V; Neelakandan D (1990) Curvature effects on the wake of an airfoil and other bodies. Fluid Dyn Res 6: 1–13
Savill AM (1983) The turbulence structure of a highly curved two-dimensional wake. IUTAM Symposium on Complex Turbulent Flows, (Dumas, R., and Fulachier, F., (eds.)) pp 185–197 Springer-Verlag, Berlin
So RMC; Mellor GL (1973) Experiments on convex curvature in turbulent boundary layers. J Fluid Mech 60: 43–62
Tulapurkara EG; Ramjee V; George J (1994) Development of wake in presence of both curvature and pressure gradient. Proc Symposium on Boundary Layer and Free Shear Flows, (Donovan, J.F. and Dutton, J.C., eds.), ASME Fluids Engineering Division 184: 195–202
Weygandt JH; Mehta RD (1993a) Effects of initial conditions on the development of curved wakes. AIAA Paper 93-0655
Weygandt JH; Mehta RD (1993b) Three-dimensional structure of straight and curved plane wakes. Dept of Aeronautics and Astronautics. Stanford University, JIAA Report TR-110
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Tulapurkara, E.G., Ramjee, V. & George, J. Development of a bluff body wake under the combined influence of curvature and pressure gradient. Experiments in Fluids 18, 311–318 (1995). https://doi.org/10.1007/BF00211386
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DOI: https://doi.org/10.1007/BF00211386