Experiments in Fluids

, Volume 53, Issue 5, pp 1317–1326 | Cite as

Separation control in a conical diffuser with an annular inlet: center body wake separation

  • Kin Pong LoEmail author
  • Christopher J. Elkins
  • John K. Eaton
Research Article


In many practical applications of conical diffusers, the flow is fed by an annular flow passage formed by a center body. Flow separation, which occurs if the center body ends abruptly, is undesirable because it degrades the diffuser performance. The present experiment utilizes magnetic resonance velocimetry to acquire three-component mean velocity measurements for a set of conical diffusers with an annular inlet. The results show strong coupling between the diffuser wall boundary layer development and the wake of the center body. Coanda blowing is used to mitigate the center body wake separation. The diffuser wall boundary layer is thick in the absence of the central separation bubble and separates when Coanda blowing is too strong.


Center Body Separation Bubble Adverse Pressure Gradient Wake Vortex Conical Diffuser 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



Funding for this research is provided by Siemens Energy. Mr. Jongmin Seo assisted with the truncated Coanda tail piece experiments. Ms. Angelina Padilla assisted with all the MRV experiments that produced the data presented in this paper.


  1. Abramson P, Rinehart C, Vukasinovic B, Glezer A (2007) Fluidic control of aerodynamic forces on a body of revolution. AIAA paperGoogle Scholar
  2. Azad RS (1996) Turbulent flow in a conical diffuser: a review. Exp Thermal Fluid Sci 13:318–337CrossRefGoogle Scholar
  3. Elkins CJ, Markl M, Pelc N, Eaton JK (2003) 4D magnetic resonance velocimetry for mean velocity measurements in complex turbulent flows. Exp Fluids 34(4):494–503Google Scholar
  4. Freund JB, Mungal MG (1994) Drag and wake modification of axisymmetric bluff bodies using Coanda blowing. J Aircraft 31(3):572–578CrossRefGoogle Scholar
  5. Klein A (1981) Review: effects of inlet conditions on conical-diffuser performance. J Fluids Eng 103:250–257CrossRefGoogle Scholar
  6. Liu X, Thomas FO, Nelson RC (2002) An experimental investigation of the planar turbulent wake in constant pressure gradient. Phys Fluids 14(8):2817–2838CrossRefGoogle Scholar
  7. Neuendorf R, Wygnanski I (1999) On a turbulent wall jet flowing over a circular cylinder. J Fluid Mech 381:1–25MathSciNetzbMATHCrossRefGoogle Scholar
  8. Newman BG (1961) The deflexion of plane jets by adjacent boundaries: coanda effect. In: Lachmann GV (ed) Boundary layer and flow control 1. Permagon, London, pp 232–264Google Scholar
  9. Rodman LC, Wood NJ, Roberts L (1989) Experimental investigation of straight and curved annular wall jets. AIAA J 27(8):1059–1067CrossRefGoogle Scholar
  10. Sovran G, Klomp ED (1967) Experimentally determined optimum geometries for rectilinear diffusers with rectangular, conical or annular cross-section. Fluid Mechanics of Internal Flow pp 270–319Google Scholar
  11. Tulapurkara EG, Ramjee V, George J (1995) Development of a bluff body wake under the combined influence of curvature and pressure gradient. Exp Fluids 18:311–318CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Kin Pong Lo
    • 1
    Email author
  • Christopher J. Elkins
    • 2
  • John K. Eaton
    • 3
  1. 1.Department of Mechanical EngineeringStanford UniversityStanfordUSA
  2. 2.Department of Mechanical EngineeringStanford UniversityStanfordUSA
  3. 3.Department of Mechanical EngineeringStanford UniversityStanfordUSA

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