Aircraft propulsion systems often use Y-shaped
subsonic diffusing ducts as twin air-intakes to supply the ambient air
into the engine compressor for thrust generation. Due to space
constraint, the diffusers need to be curved, which causes severe flow
non-uniformity at the engine face. The present study attempt to
control flow in a mild-curved Y-duct diffuser using trapezoidalshaped
vortex generators (VG) attached on either both the sidewalls
or top and bottom walls of the diffuser at the inflexion plane. A
commercial computational fluid dynamics (CFD) code is modified
and is used to simulate the effects of SVG in flow of a Y-duct
diffuser. A few experiments are conducted for CFD code validation,
while the rest are done computationally. The best combination of Yduct
diffuser is found with VG-2 arranged in co-rotating sequence
and attached to both the sidewalls, which ensures highest static
pressure recovery, lowest total pressure loss, minimum flow
distortion and less flow separation in Y-duct diffuser. The decrease in
VG height while attached to top and bottom walls further improves
axial flow uniformity at the diffuser outlet by a great margin as
compared to the bare duct.
[1] J. Seddon, and E. L. Goldsmith, Intake Aerodynamics, Collins
Professional Books, London, 1985.
[2] D. D. William, and L. E. Surber, Intake Engine Compatibility, In:
Goldsmith, E.L., Seddon (Eds.), Practical Intake Aerodynamic Design,
Blackwell Scientific Publications, Oxford, pp. 1993, 21-71.
[3] J. C. Lin, G. V. Selvy, F. G. Howard, "Exploratory study on vortex
generator devices for turbulent flow separation control", AIAA paper No.
AIAA-91-0042, 1991.
[4] B. A. Reichert, and B. J. Wendt, "Improving diffusing S-duct
performance by secondary flow control" , NASA Technical
Memorandum 106492, 1994.
[5] R. K. Sullerey, S. Mishra, and A. M. Pradeep, "Application of boundary
layer fences and vortex generators in improving performance of S-duct
diffusers", ASME J. of Fluids Engineering, vol. 124, no. 3, pp. 136-142,
2002.
[6] O. E. Abdellatif, "Experimental study of turbulent flow characteristics
inside a rectangular S-shaped diffusing duct", AIAA paper No. AIAA-
2006-1501, 2006.
[7] R. W. Fox, and S. J. Kline, "Flow regimes in curved subsonic diffusers",
Journal of Basic Engineering, vol. 84, pp. 303-316, 1962.
[8] K. A. Ahmad, J. K. Watterson, J. S. Cole, and I. Briggs, "Sub-boundary
layer vortex generator control of a separated diffuser flow", AIAA paper
No. 2005-4650, 2005.
[9] A. R. Paul, K. Kuppa, M. S. Yadav, and U. Dutta, "Flow improvement in
rectangular air-intake by submerged vortex generators, Journal of
Applied Fluid Mechanics, vol. 4, no. 2, 2011 (to be published in July
2011).
[10] S. B. Pope, Turbulent Flows, 6th Reprint, Cambridge Univ. Press, NY,
2009, pp. 373-384.
[11] W. P. Jones, and B. E. Launder, "The prediction of laminarization with a
two-equation model of turbulence", Int. J. of Heat and Mass Transfer,
vol. 15, pp. 301-314, 1972.
[12] B. E. Launder, and B. I. Sharma, "Application of the energy-dissipation
model of turbulence to the calculation of flow near a spinning disc",
Letters of Heat and Mass Transfer, vol. 1, pp. 131-138, 1974.
[13] B. E. Launder, Phenomenological Modeling: Present... and Future?, In:
J.L. Lumley (Ed.), Whither Turbulence? Turbulence at the Crossroads,
Springer-Verlag, Berlin, 1990, pp. 439-485.
[14] K. Hanjalić, "Advanced turbulence closure models: A view of current
status and future prospects", J. of Heat and Fluid Flow, vol. 15, pp. 178-
203, 1994.
[15] V. Yakhot, and S. A. Orszag, "Renormalized group analysis of
turbulence: I. Basic theory", J. of Scientific Computation, vol. 1, 1986,
pp. 3-51.
[16] L. M. Smith, and W. C. Reynolds, "On the Yakhot-Orszag
renormalization group method for deriving turbulence statistics and
models", Physics of Fluids, vol. A4, pp. 364-390, 1992.
[17] L. M. Smith, and S. L. Woodruff, "Renormalization-group analysis of
turbulence", Annual Review of Fluid Mechanics, vol. 30, pp. 275-310,
1998.
[18] S. A. Orszag, I. Staroselsky, W. S. Flannery and Y. Zhang, Introduction
to renormalization group modeling of turbulence, In. T. B. Gatski, M. Y.
Hussaini and J. L. Lumly (Eds.), Simulation and Modeling of Turbulent
Flows, Oxford Univ. Press, NY, Chapter 4, 1996, pp. 155-183.
[19] D. Choudhury, Introduction to the renormalization group method and
turbulence modeling, Fluent Technical Memorandum 107, 1993,
Lebanon, NH.
[20] S. V. Patankar, Numerical Heat Transfer and Fluid Flow, Taylor and
Francis Publication, London, 1980.
[1] J. Seddon, and E. L. Goldsmith, Intake Aerodynamics, Collins
Professional Books, London, 1985.
[2] D. D. William, and L. E. Surber, Intake Engine Compatibility, In:
Goldsmith, E.L., Seddon (Eds.), Practical Intake Aerodynamic Design,
Blackwell Scientific Publications, Oxford, pp. 1993, 21-71.
[3] J. C. Lin, G. V. Selvy, F. G. Howard, "Exploratory study on vortex
generator devices for turbulent flow separation control", AIAA paper No.
AIAA-91-0042, 1991.
[4] B. A. Reichert, and B. J. Wendt, "Improving diffusing S-duct
performance by secondary flow control" , NASA Technical
Memorandum 106492, 1994.
[5] R. K. Sullerey, S. Mishra, and A. M. Pradeep, "Application of boundary
layer fences and vortex generators in improving performance of S-duct
diffusers", ASME J. of Fluids Engineering, vol. 124, no. 3, pp. 136-142,
2002.
[6] O. E. Abdellatif, "Experimental study of turbulent flow characteristics
inside a rectangular S-shaped diffusing duct", AIAA paper No. AIAA-
2006-1501, 2006.
[7] R. W. Fox, and S. J. Kline, "Flow regimes in curved subsonic diffusers",
Journal of Basic Engineering, vol. 84, pp. 303-316, 1962.
[8] K. A. Ahmad, J. K. Watterson, J. S. Cole, and I. Briggs, "Sub-boundary
layer vortex generator control of a separated diffuser flow", AIAA paper
No. 2005-4650, 2005.
[9] A. R. Paul, K. Kuppa, M. S. Yadav, and U. Dutta, "Flow improvement in
rectangular air-intake by submerged vortex generators, Journal of
Applied Fluid Mechanics, vol. 4, no. 2, 2011 (to be published in July
2011).
[10] S. B. Pope, Turbulent Flows, 6th Reprint, Cambridge Univ. Press, NY,
2009, pp. 373-384.
[11] W. P. Jones, and B. E. Launder, "The prediction of laminarization with a
two-equation model of turbulence", Int. J. of Heat and Mass Transfer,
vol. 15, pp. 301-314, 1972.
[12] B. E. Launder, and B. I. Sharma, "Application of the energy-dissipation
model of turbulence to the calculation of flow near a spinning disc",
Letters of Heat and Mass Transfer, vol. 1, pp. 131-138, 1974.
[13] B. E. Launder, Phenomenological Modeling: Present... and Future?, In:
J.L. Lumley (Ed.), Whither Turbulence? Turbulence at the Crossroads,
Springer-Verlag, Berlin, 1990, pp. 439-485.
[14] K. Hanjalić, "Advanced turbulence closure models: A view of current
status and future prospects", J. of Heat and Fluid Flow, vol. 15, pp. 178-
203, 1994.
[15] V. Yakhot, and S. A. Orszag, "Renormalized group analysis of
turbulence: I. Basic theory", J. of Scientific Computation, vol. 1, 1986,
pp. 3-51.
[16] L. M. Smith, and W. C. Reynolds, "On the Yakhot-Orszag
renormalization group method for deriving turbulence statistics and
models", Physics of Fluids, vol. A4, pp. 364-390, 1992.
[17] L. M. Smith, and S. L. Woodruff, "Renormalization-group analysis of
turbulence", Annual Review of Fluid Mechanics, vol. 30, pp. 275-310,
1998.
[18] S. A. Orszag, I. Staroselsky, W. S. Flannery and Y. Zhang, Introduction
to renormalization group modeling of turbulence, In. T. B. Gatski, M. Y.
Hussaini and J. L. Lumly (Eds.), Simulation and Modeling of Turbulent
Flows, Oxford Univ. Press, NY, Chapter 4, 1996, pp. 155-183.
[19] D. Choudhury, Introduction to the renormalization group method and
turbulence modeling, Fluent Technical Memorandum 107, 1993,
Lebanon, NH.
[20] S. V. Patankar, Numerical Heat Transfer and Fluid Flow, Taylor and
Francis Publication, London, 1980.
@article{"International Journal of Mechanical, Industrial and Aerospace Sciences:60935", author = "Akshoy R. Paul and Pritanshu Ranjan and Ravi R. Upadhyay and Anuj Jain", title = "Passive Flow Control in Twin Air-Intakes", abstract = "Aircraft propulsion systems often use Y-shaped
subsonic diffusing ducts as twin air-intakes to supply the ambient air
into the engine compressor for thrust generation. Due to space
constraint, the diffusers need to be curved, which causes severe flow
non-uniformity at the engine face. The present study attempt to
control flow in a mild-curved Y-duct diffuser using trapezoidalshaped
vortex generators (VG) attached on either both the sidewalls
or top and bottom walls of the diffuser at the inflexion plane. A
commercial computational fluid dynamics (CFD) code is modified
and is used to simulate the effects of SVG in flow of a Y-duct
diffuser. A few experiments are conducted for CFD code validation,
while the rest are done computationally. The best combination of Yduct
diffuser is found with VG-2 arranged in co-rotating sequence
and attached to both the sidewalls, which ensures highest static
pressure recovery, lowest total pressure loss, minimum flow
distortion and less flow separation in Y-duct diffuser. The decrease in
VG height while attached to top and bottom walls further improves
axial flow uniformity at the diffuser outlet by a great margin as
compared to the bare duct.", keywords = "Twin air-intake, Vortex generator (VG), Turbulence
model, Pressure recovery, Distortion coefficient", volume = "5", number = "5", pages = "922-8", }
