Abstract
Round air jet development downstream from an abrupt contraction coupled to a uniform circular tube extension with length to diameter ratio L/D = 1.2 and L/D = 53.2 is studied experimentally. Smoke visualisation and systematic hot film velocity measurements are performed for low to moderate Reynolds numbers 1130 < Re b < 11320. Mean and turbulent velocity profiles are quantified at the tube exit and along the centerline from the tube exit down to 20 times the diameter D. Flow development is seen to be determined by the underlying jet structure at the tube exit which depends on Reynolds number, initial velocity statistics at the tube exit and the presence/absence of coherent structures. It is shown that the tube extension ratio L/D as well as the sharp edged abrupt contraction influence the initial jet structure at the tube exit. For both L/D ratios, the presence of the abrupt contraction results in transitional jet flow in the range 2000 < Re b < 4000 and in flow features associated with forced jets and high Reynolds numbers Re b > 104. The tube extension ratio L/D downstream from the abrupt contraction determines the shear layer roll up so that for L/D = 1.2 flow visualisation suggests the occurrence of toroidal vortices for Re b < 4000 whereas helical vortices are associated with the transitional regime for L/D = 53.2. Found flow features are compared to features reported in literature for smooth contraction nozzles and long pipe flow.
Similar content being viewed by others
References
O’Neill, P., Soria, J., Honnery, D.: The stability of low Reynolds number round jets. Exp. Fluids 36, 473–483 (2004)
Abdel-Rahman, A., Al-Fahed, S., Chakroun, W.: The near-field characteristics of circular jets at low Reynolds numbers. Mech. Res. Commun. 23, 313–324 (1996)
Boguslawski, L., Popiel, C.O.: Flow structure of the free round turbulent jet in the initial region. J. Fluid Mech. 90, 531–539 (1979)
Burattini, P., Antonia, R.A., Rajagopalan, S., Stephens, M.: Effect of initial conditions on the near-field development of a round jet. Exp. Fluids 37, 56–64 (2004)
Burattini, P., Djenidi, L.: Velocity and passive scalar characteristics round jet with grids at the nozzle exit. Flow Turbulence Combust. 72, 199–218 (2004)
Cohen, J., Wygnanski, I.: The evolution of instabilities in the axisymmetric jet. part 1. The linear growth of disturbances near the nozzle. J. Fluid Mech. 176, 191–219 (1987)
Crow, S.C., Champagne, F.H.: Orderly structure in jet turbulence. J. Fluid Mech. 48, 547–591 (1971)
Dimotakis, P.E., Miake-Lye, R.C., Papantoniou, D.A.: Structure and dynamics of round turbulent jets. Phys. Fluids 23, 3185–3192 (1983)
Drubka, R., Reisenthel, P., Nagib, H.: The dynamics of low initial disturbance turbulent jets. Phys. Fluids A 1, 1723–1735 (1989)
Eckmann, J.P.: Roads to turbulence in dissipative dynamical systems. Rev. Mod. Phys. 53, 643–654 (1981)
Ferdman, E., Otugen, M., Kim, S.: Effect of initial velocity profiles on round jets. J. Propuls. Power 16, 676–686 (2000)
George, W.K.: Recent advances in Turbulence, chapter the self-preservation of turbulent flows and its relation to initial conditions and coherent structures, pp. 39–73. Hemisphere, New York (1989)
Grandchamp, X.: Modélisation Physique des Écoulements Turbulents Appliquée aux voies Aériennes Supérieures Chez l’humain. PhD thesis, Grenoble University (2009)
Grandchamp, X., Van Hirtum, A., Pelorson, X.: Hot film/wire calibration for low to moderate flow velocities. Meas. Sci. Technol. 21, 115402 (2010)
Grinstein, F.F., Glauser, M.N., George, W.K.: Fluid vortices. In: chapter Vorticity in jets, pp. 65–94. Kluwer Academic Publisher, New York (1995)
Harsha, P.T.: Free turbulent mixing: a critical evaluation of theory and experiment. Technical report (1971)
Ho, C., Huerre, P.: Perturbed free shear layers. Annu. Rev. Fluid Mech. 16, 365–424 (1984)
Hussain, A., Zedan, M.: Effects of the initial condition on the axisymmetric free shear layer: effects of the initial momentum thickness. Phys. Fluids 20, 1100–1112 (1978)
Hussein, H., Capp, S., George, W.: Velocity measurements in a high Reynolds number momentum conserving axisymmetric turbulent jet. J. Fluid Mech. 258, 31–75 (1994)
Iyogun, C.O., Birouk, M.: Effect of sudden expansion on entrainment and spreading rates of a jet issuing from asymmetric nozzles. Flow Turbul. Combust. 82, 287–315 (2009)
Kwon, S.J., Seo, I.W.: Reynolds number effects on the behavior of a non-buoyant round jet. Exp. Fluids 38, 801–812 (2005)
Lee, S.S., Liu, J.T.C.: Multiple lare-scale coherent mode interactions in a developing round jet. J. Fluid Mech. 248, 383–401 (1993)
Liepmann, D., Gharib, M.: The role of streamwise vorticity in the near-field entrainment of round jets. J. Fluid Mech. 245, 643–668 (1992)
Malmström, T.G., Kirkpatrick, A.T., Christensen, B., Knappmiller, K.D.: Centreline velocity decay measurements in low-velocity axisymmetric jets. J. Fluid Mech. 246, 363–377 (1997)
Mi, J., Kalt, P., Nathan, G., Wong, C.: PIV measurements of a turbulent jet issuing from round sharp-edged plate. Exp. Fluids 42(2), 625–637 (2007)
Mi, J., Nathan, G., Luxton, R.: Centreline mixing characteristics of jets from nine differently shaped nozzles. Exp. Fluids 28(2), 93–94 (2000)
Mi, J., Nobes, D., Nathan, G.: Influence of jet exit conditions on the passive scalar field of an axisymmetric free jet. J. Fluid Mech. 432, 91–125 (2001)
Michalke, A. On spatially growing disturbances in an inviscid shear layer. J. Fluid Mech. 23, 521–544 (1965)
Michalke, A., Hermann, G.: On the inviscid instability of a circular jet with external flow. J. Fluid Mech. 114, 343–359 (1982)
Mikhail, M.N.: Optimum design of wind tunnel contractions. AIAA J. 17, 471–477 (1979)
Morel, T.: Comprehensive design of axisymmetric wind tunnel contractions. J. Fluid Eng. 97, 225–233 (1975)
Panchapakesan, N., Lumley, J.: Turbulence measurements in axisymmetric jets of air and helium. Part 1. Air jet. J. Fluid Mech. 246, 197–224 (1993)
Pitts, W.: Reynolds number effects on the mixing behavior of axisymmetric turbulent jets. Exp. Fluids 11, 135–141 (1991)
Quinn, W.: Upstream nozzle shaping effects on near field flow in round turbulent free jets. Eur. J. Mech. B, Fluids 25, 279–301 (2006)
Romano, G., Antonia, R.A.: Longitudinal and transverse structure functions in a turbulent round jet: effect of initial conditions and Reynolds number. J. Fluid Mech. 436, 231–248 (2001)
Russ, S., Strykowski, P.: Turbulent structure and entrainment in heated jets: The effect of initial conditions. Phys. Fluids 5, 3216–3225 (1993)
Saffman, P.G.: Vortex dynamics. CambridgeMonographs on Mechanics and AppliedMathematics, pp. 1–311. New York (2001)
Sautet, J., Stepowski, D.: Dynamic behavior of variable-density, turbulent jets in their near development fields. Phys. Fluids 7(2), 2796–2806 (1995)
Schlichting, H., Gersten, K.: Boundary Layer Theory. Springer Verlag, Berlin (2000)
Todde, V., Spazzini, P.G., Sandberg, M.: Experimental analysis of low-Reynolds number free jets: evolution along the jet centerline and Reynolds number effects. Exp. Fluids 47, 279–294 (2009)
Van Hirtum, A., Grandchamp, X., Pelorson, X.: Moderate Reynolds number axisymmetric jet development downstream an extended conical diffuser: influence of extension length. Eur. J. Mech. B, Fluids 28, 753–760 (2009)
Winant, C.D., Browand, F.K.: Vortex pairing: the mechanism of turbulent mixing-layer growth at moderate Reynolds number. J. Fluid Mech. 63, 237–255 (1974)
Wygnanski, I., Sokolov, M., Friedman, D.: On transition in a pipe: Part 2. The equilibrium puff. J. Fluid Mech. 69, 283–304 (1975)
Wygnanski, I.J., Champagne, F.H.: On transition in a pipe: Part 1. The origin of puffs and slugs and the flow in a turbulent slug. J. Fluid Mech. 59, 281–335 (1973)
Xu, G., Antonia, R.A.: Effect of different initial conditions on a turbulent round free jet. Exp. Fluids 33, 677–683 (2002)
Zaouali, Y., Filali, T., Ben, H., Aissia, Jay, J.: Flow structure generated from an axisymmetric natural air jet at a moderate reynolds number. Fluid Dyn. Res. 43, 1–13 (2011)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Grandchamp, X., Van Hirtum, A. Near Field Round Jet Flow Downstream from an Abrupt Contraction Nozzle with Tube Extension. Flow Turbulence Combust 90, 95–119 (2013). https://doi.org/10.1007/s10494-012-9429-5
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10494-012-9429-5