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Abstract
Low Reynolds flow continues to get researchers attention for its relevance in a number of areas including the flight regimes of Micro Air Vehicle (MAV). The Laminar Separation Bubble (LSB) which is largely responsible for the non-linear aerodynamic characteristics have been studied both numerically and experimentally. In this work, a high fidelity computation was carried out to study LSB as well as the dependence of aerodynamic characteristics on a symmetrical thick airfoil at low Reynolds numbers. Flow structure in the bubble is clearly brought out with the appropriate selection of turbulence model in the solver. Also, the extent of LSB was well predicted by transition SST turbulence model in the solver. A novel approach has been made to obtain the location and length of LSB using the values of wall shear stress and the results are encouraging. Also, a comparative analysis of flow transition and surface pressure distribution was made by four different turbulence models and the results are discussed.
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References
- Mueller, T. J. and DeLaurier, J.D., "Aerodynamics of Small Vehicles" Annual Review of Fluid Mechanics, Vol.35, 2003, pp.89-111.
- Horton H. P., "Laminar Separation Bubble in Two and Three Dimensional Incompressible Flow", University of London, UK, 1968.
- Marchman, J. F., "Aerodynamic Testing at Low Reynolds Numbers", Journal of Aircraft, Vol.24, No.2, 1987, pp.107-114.
- Mueller, T. J., "The Influence of Laminar Separation and Transition on Low Reynolds Number Airfoil Hysteresis", Journal of Aircraft, Vol.22, No.9, 1985, pp.763-770.
- Hoffman, J. A., "Effect of Free Stream Turbulence on the Performance Characteristics of an Airfoil", AIAA Journal, Vol.29, No.9, 1991, pp.1353-1354.
- Brendel, M. and Mueller, T. J., "Boundary Layer Measurements on an Airfoil at Low Reynolds Number", Journal of Aircraft, Vol.25, No.7, 1988, pp.612617.
- O’Meara, M. M. and Mueller, T. J., "Laminar Separation Bubble Characteristics on a n Airfoil at Low Reynolds Number", AIAA Journal, Vol.25, No.8, 1987, pp.1033-1041.
- Weibust, E., Bertelrud, A. and Ridder, S. O., "Experimental Investigation of Laminar Separation Bubble and Comparison with Theory", Journal of Aircraft, Vol.24, No.5, 1987, pp.291-297.
- McCroskey, W. J., "A Critical Assessment of Wind Tunnel Results for the NACA 0012 Airfoil", NASA TM 100019, October, 1987.
- Izzet, S. and Adem, A., "Numerical and Experimental Investigations of Lift and Drag Performances of NACA 0015 Wind Turbine Airfoil", International Journal of Materials, Mechanics and Manufacturing, Vol.3, No.1, February, 2015.
- Harry J. Goett and Kenneth Bulivant, W., "Tests of NACA 0009, 0012, 0018 Airfoils in the Full Scale Tunnel", Report No.647, 1937.
- Trimmer, W. A., "Two dimensional low reynolds Number Wind Tunnel Results for Airfoil NACA 0018", Wind Energy, Vol.32, No.6, 2008, pp.525537.
- Gerakopulos, R. and Boutilier, M.S.H., "Aerodynamic Characterization of a NACA 0018 Airfoil at Low Reynolds Numbers", 10th Fluid Dynamics Conference and Exhibit, 26th June to 1st July, 2010, Chicago, Illinois.
- Genc, M. S., Lock, G. D.and Kayank, U., "An Experimental and Computational Study of Low Re Number Transitional Flows Over an Airfoil with Leading Edge Slat", 8th AIAA Aviation Technology, Integration and Operations Conference, 14-19, September, 2008, USA.
- Catalano, P. and Tognaccini, R., "RANS Analysis of Low Reynolds Number Flow Around the SD7003 Airfoil", Aerospace Science Technology, 15, 2010, pp.615-626.
- Serdar Gen, M., Ünver Kaynak and Hüseyin Yapici., "Performance of Transition Model for Predicting Low Re Aerofoil Flows Without/With Single and Simultaneous Blowing and Suction", European Journal of Mechanics B/Fluids, 30, 2011, pp.218-235.
- Ilyas Karasu, M., Serdar Gen and Hakan Aikel, H., "Numerical Study on Low Reynolds Number Flows Over an Aerofoil", Jl. Appl Mech Engineering, Vol.2, No.5, 1000131, 2013.
- Elia Daniele., "Numerical and Experimental Investigation of Low Reynolds Number Wind Turbine Airfoils Under Stall and Post-stall Conditions", Ph.D Thesis, Department of Industrial Engineering, University of Naples, Federico II Naples, April, 2013.
- Ji Yaoa., Weibin Yuanb., Jianliang Wanga., Jianbin Xiec., Haipeng Zhoub., Mingjun Pengd and Yong Sund., "Numerical Simulation of Aerodynamic Performance for Two Dimensional Wind Turbine Airfoils", International Conference on Advances in Computational Modeling and Simulation, Procedia Engineering, 31, 2012, pp.80-86.
- Gasser E. Hassan., Hassan, A. and Youssef, M. E., "Numerical Investigation of Medium Range Reynolds Number Aerodynamics Characteristics for NACA0018 Airfoil", CFD Letters, Vol.6, No.4, December, 2014.
- Cebeci, T., Mosinskis, G. J. and Smith, A. M. O., "Calculation of Separation Points in Incompressible Turbulent Flows", Journal of Aircraft, 9, 1972, pp.618- 624.
- Wilcox, D. C., "Simulation of Transition with Two Equation Turbulence Model", AIAA Journal, 32, 1994, pp.247- 255.
- Abu-Ghannam, B. J. and Shaw, R., "Natural Transition of Boundary Layers- the Effect of Turbulence, Pressure Gradient, and Flow History", Journal of Mechanical Engineering Science, 22, 1980, pp.213228.
- Langtry, R. B. and Menter, F. R., "Transition Modeling for General CFD Applications in Aeronautics",
- AIAA Paper 2005-0522, 2005.
- Walters, D. K. and Cokljat, D., "A Three-Equation Eddy-Viscosity Model for Reynolds-Averaged
- Navier-Stokes Simulations of Transitional Flow", ASME Jl Fluids Engineering, 130, 121401 / 1-
- /14, 2008.
- Menter, F., "Two-equation Eddy Viscosity Turbulence Models for Engineering Applications", AIAA
- Journal, 32, 1994, pp.1598-1605.
- ANSYS Fluent Theory Guide, ANSYS Inc., USA, Release 15.0.
- Charmichael, B. H., "Low Reynolds Number Airfoil Survey", NASA CR No.165803, Vol.1, 1981.
- Jacobs, E. N. and Sherman, A., "Airfoil Section Characteristics as Affected by Variations of the
- Reynolds Number", NACA TR No.586, 1937.
- Triton, D. J., "Physical Fluid Dynamics", Oxford Science Publication, 1988.
- Lambert, A. R. and Yarusevych, S., "Characterization of Vortex Dynamics in a Laminar Separation Bubble", Paper 2015, 2628, 45th AIAA Fluid Dynamics Conference, Dallas, TX, 22-2, M. Bagade,
- S. B. Krishnan, 6th June, 2015.
- Bagade, P. M., Krishnan, S. B. and Sengupta, T. K., "DNS of Low Reynolds Number Aerodynamics in
- Presence of Free Stream Turbulence", Frontiers in Aerospace Engineering, Vol.4, No.1, May, 2015.
- Luca Brandt., Philipp Schlatter and Henningson, D. S., "Transition in Boundary Layers Subject to Free
- Stream Turbulence", Jl. Fluid Mech., 2004, pp.167- 198.
- John McArthur., "Aerodynamics of Wings at Low Reynolds Numbers", Ph. D Thesis, Aerospace and
- Mechanical Engineering, University of Southern California, 2007.
References
Mueller, T. J. and DeLaurier, J.D., "Aerodynamics of Small Vehicles" Annual Review of Fluid Mechanics, Vol.35, 2003, pp.89-111.
Horton H. P., "Laminar Separation Bubble in Two and Three Dimensional Incompressible Flow", University of London, UK, 1968.
Marchman, J. F., "Aerodynamic Testing at Low Reynolds Numbers", Journal of Aircraft, Vol.24, No.2, 1987, pp.107-114.
Mueller, T. J., "The Influence of Laminar Separation and Transition on Low Reynolds Number Airfoil Hysteresis", Journal of Aircraft, Vol.22, No.9, 1985, pp.763-770.
Hoffman, J. A., "Effect of Free Stream Turbulence on the Performance Characteristics of an Airfoil", AIAA Journal, Vol.29, No.9, 1991, pp.1353-1354.
Brendel, M. and Mueller, T. J., "Boundary Layer Measurements on an Airfoil at Low Reynolds Number", Journal of Aircraft, Vol.25, No.7, 1988, pp.612617.
O’Meara, M. M. and Mueller, T. J., "Laminar Separation Bubble Characteristics on a n Airfoil at Low Reynolds Number", AIAA Journal, Vol.25, No.8, 1987, pp.1033-1041.
Weibust, E., Bertelrud, A. and Ridder, S. O., "Experimental Investigation of Laminar Separation Bubble and Comparison with Theory", Journal of Aircraft, Vol.24, No.5, 1987, pp.291-297.
McCroskey, W. J., "A Critical Assessment of Wind Tunnel Results for the NACA 0012 Airfoil", NASA TM 100019, October, 1987.
Izzet, S. and Adem, A., "Numerical and Experimental Investigations of Lift and Drag Performances of NACA 0015 Wind Turbine Airfoil", International Journal of Materials, Mechanics and Manufacturing, Vol.3, No.1, February, 2015.
Harry J. Goett and Kenneth Bulivant, W., "Tests of NACA 0009, 0012, 0018 Airfoils in the Full Scale Tunnel", Report No.647, 1937.
Trimmer, W. A., "Two dimensional low reynolds Number Wind Tunnel Results for Airfoil NACA 0018", Wind Energy, Vol.32, No.6, 2008, pp.525537.
Gerakopulos, R. and Boutilier, M.S.H., "Aerodynamic Characterization of a NACA 0018 Airfoil at Low Reynolds Numbers", 10th Fluid Dynamics Conference and Exhibit, 26th June to 1st July, 2010, Chicago, Illinois.
Genc, M. S., Lock, G. D.and Kayank, U., "An Experimental and Computational Study of Low Re Number Transitional Flows Over an Airfoil with Leading Edge Slat", 8th AIAA Aviation Technology, Integration and Operations Conference, 14-19, September, 2008, USA.
Catalano, P. and Tognaccini, R., "RANS Analysis of Low Reynolds Number Flow Around the SD7003 Airfoil", Aerospace Science Technology, 15, 2010, pp.615-626.
Serdar Gen, M., Ünver Kaynak and Hüseyin Yapici., "Performance of Transition Model for Predicting Low Re Aerofoil Flows Without/With Single and Simultaneous Blowing and Suction", European Journal of Mechanics B/Fluids, 30, 2011, pp.218-235.
Ilyas Karasu, M., Serdar Gen and Hakan Aikel, H., "Numerical Study on Low Reynolds Number Flows Over an Aerofoil", Jl. Appl Mech Engineering, Vol.2, No.5, 1000131, 2013.
Elia Daniele., "Numerical and Experimental Investigation of Low Reynolds Number Wind Turbine Airfoils Under Stall and Post-stall Conditions", Ph.D Thesis, Department of Industrial Engineering, University of Naples, Federico II Naples, April, 2013.
Ji Yaoa., Weibin Yuanb., Jianliang Wanga., Jianbin Xiec., Haipeng Zhoub., Mingjun Pengd and Yong Sund., "Numerical Simulation of Aerodynamic Performance for Two Dimensional Wind Turbine Airfoils", International Conference on Advances in Computational Modeling and Simulation, Procedia Engineering, 31, 2012, pp.80-86.
Gasser E. Hassan., Hassan, A. and Youssef, M. E., "Numerical Investigation of Medium Range Reynolds Number Aerodynamics Characteristics for NACA0018 Airfoil", CFD Letters, Vol.6, No.4, December, 2014.
Cebeci, T., Mosinskis, G. J. and Smith, A. M. O., "Calculation of Separation Points in Incompressible Turbulent Flows", Journal of Aircraft, 9, 1972, pp.618- 624.
Wilcox, D. C., "Simulation of Transition with Two Equation Turbulence Model", AIAA Journal, 32, 1994, pp.247- 255.
Abu-Ghannam, B. J. and Shaw, R., "Natural Transition of Boundary Layers- the Effect of Turbulence, Pressure Gradient, and Flow History", Journal of Mechanical Engineering Science, 22, 1980, pp.213228.
Langtry, R. B. and Menter, F. R., "Transition Modeling for General CFD Applications in Aeronautics",
AIAA Paper 2005-0522, 2005.
Walters, D. K. and Cokljat, D., "A Three-Equation Eddy-Viscosity Model for Reynolds-Averaged
Navier-Stokes Simulations of Transitional Flow", ASME Jl Fluids Engineering, 130, 121401 / 1-
/14, 2008.
Menter, F., "Two-equation Eddy Viscosity Turbulence Models for Engineering Applications", AIAA
Journal, 32, 1994, pp.1598-1605.
ANSYS Fluent Theory Guide, ANSYS Inc., USA, Release 15.0.
Charmichael, B. H., "Low Reynolds Number Airfoil Survey", NASA CR No.165803, Vol.1, 1981.
Jacobs, E. N. and Sherman, A., "Airfoil Section Characteristics as Affected by Variations of the
Reynolds Number", NACA TR No.586, 1937.
Triton, D. J., "Physical Fluid Dynamics", Oxford Science Publication, 1988.
Lambert, A. R. and Yarusevych, S., "Characterization of Vortex Dynamics in a Laminar Separation Bubble", Paper 2015, 2628, 45th AIAA Fluid Dynamics Conference, Dallas, TX, 22-2, M. Bagade,
S. B. Krishnan, 6th June, 2015.
Bagade, P. M., Krishnan, S. B. and Sengupta, T. K., "DNS of Low Reynolds Number Aerodynamics in
Presence of Free Stream Turbulence", Frontiers in Aerospace Engineering, Vol.4, No.1, May, 2015.
Luca Brandt., Philipp Schlatter and Henningson, D. S., "Transition in Boundary Layers Subject to Free
Stream Turbulence", Jl. Fluid Mech., 2004, pp.167- 198.
John McArthur., "Aerodynamics of Wings at Low Reynolds Numbers", Ph. D Thesis, Aerospace and
Mechanical Engineering, University of Southern California, 2007.