Wing Airfoil Flow-Around Specifics and Its Aerodynamic Characteristics nearby the Hard Surface of Media Separation over a Standard Obstacle

Aeronautical and Space-Rocket Engineering


Аuthors

Krivel' S. M.1, 2*, Vshivkov Y. F.1**

1. Irkutsk state university, Irkutsk, Russia
2. Irkutsk National Research Technical University, 83, Lermontov str., Irkutsk, 664074, Russia

*e-mail: krivel66@mail.ru
**e-mail: 1988ufv@mail.ru

Abstract

The article provides a brief overview of methods for determining aerodynamic characteristics and studying the motion parameters of a profile (aircraft, ground effect vehicle) in flight over a non-smooth underlying surface. As a rule, a wavy surface is being considered as a non-smooth underlying surface. In the works devoted to the study of the apparatus motion near a non-smooth surface, the main factor determining specifics of the airfoil flow-around and aerodynamic characteristics is the geometric distance from the airfoil characteristic point to the surface under the airfoil. As a rule, the features of the dynamic processes of airfoil flow-around are not being accounted for (as an assumption) in such studies. The article proposes a technique for studying the non-stationary aerodynamic characteristics of a wing airfoil in an unconverted motion at an unsmooth solid interface applying CFD systems based on a tunable grids toolkit. In the considered works of a number of authors, a method for modeling a wavy surface is used by “running” at a given speed of the wavy surface itself onto the design zone around a fixed profile or body. The present article employs a different approach. The movement of the wing airfoil in a virtual wind tunnel with a given law of motion over the boundary simulating the underlying surface is being modeled. The shape of the underlying surface and the law of motion of the airfoil can be quite arbitrary. This is the particular advantage of the proposed approach. It should be noted that in this case, the required computational time is potentially increased, since it may be necessary to use a computational grid in a relatively larger computational area. The article presents the results of modeling the airfoil motion in the vicinity of a local change in the shape of the underlying surface, and provides examples of research results. Specifics of the profile flow and changes in aerodynamic characteristics in flight when passing over a standard obstacle, namely, a stepwise change in the separation of the profile from the interface, are revealed. The dependences of the aerodynamic coefficients of the profile on time during the movement with various kinematic parameters over irregularities of various shapes are obtained. It has been revealed that the strongest dynamic effect of the unevenness on the flow around the profile is manifested during the time of the airfoil trailing edge passage directly in the vicinity of the local unevenness. Application of the obtained results in a number of practical tasks, such as in the problem of the airfoil optimal movement over a non-smooth surface according to some criterion, requires representation of the specifics of aerodynamic characteristics in the form of a mathematical operator. A method is proposed for representing the dependence of the aerodynamic coefficients of the profile on the parameter of the distance between the characteristic point of the profile and the underlying surface in the form of a mathematical operator obtained by system identification methods. In particular, the article provides an example of the mathematical operator representation in the form of a transfer function. The article presents an example of a mathematical operator description with transfer function parameters obtained by the MATLAB System Identification methods.

Keywords:

transonic flutter, shock wave, amplitude of limit cycle oscillations, aerodynamic damping, elastic structure

References

  1. Tichy L., Mai H., Fehrs M. et al. Risk analysis for flutter of laminar wings. In: 17th International Forum on Aeroelasticity and Structural Dynamics (June 25–28, 2017; Como, Italy). IFASD-2017-19.
  2. Kuz'mina S.I., Ishmuratov F.Z., Karas' O.V. Metod for solving a related problem of interaction of an elastic structure with a transonic flow. In: XII Vserossiiskii s"ezd po fundamental'nym problemam teoreticheskoi i prikladnoi mekhaniki (August 19–24, 2019; Bashkirskii gosudarstvennyi universitet, Ufa). Vol. 4. p. 270–272. (In Russ.).
  3. Heeg J., Chwalowski P. Predicting Transonic Flutter Using Nonlinear Computational Simulations. In: 18th International Forum on Aeroelasticity and Structural Dynamics (IFASD-2019; June 10–13, 2019; Savannah, Georgia, USA). IFASD-2019-7.
  4. Dowell E., Edwards J., Strganac T. Nonlinear Aeroelasticity. Journal of Aircraft. 2003; 40(5):857-874. DOI: 10.2514/2.6876
  5. Hebler A., Schojda L., Mai H. Experimental Investigation of the Aeroelastic Behavior of a Laminar Airfoil in transonic flow. In: International Forum on Aeroelasticity and Structural Dynamics (IFASD 2013; June 24–27, 2013; Bristol).
  6. Braune M., Hebler A. Mechanisms of Transonic Single Degree of Freedom Flutter of a Laminar Airfoil. In: 18th International Forum on Aeroelasticity and Structural Dynamics (IFASD 2019; June 10–13, 2019; Savannah, Georgia, USA). IFASD-2019-132.
  7. Jonsson E., Riso C., Lupp C.A. Flutter and Post-Flutter Constraints in Aircraft Design Optimization. Progress in Aerospace Sciences. 2019;109:100537. DOI: 10.1016/j.paerosci.2019.04.001
  8. Kuzmina S.I., Karas O.V., Ishmuratov F.Z. et al. Investigation of interaction of shock movement with structural elastic deformations in transonic flow. In: International Forum on Aeroelasticity and Structural Dynamics (IFASD 2013; 24–27 June 2013; Bristol).
  9. Edwards J., Wieseman C. Flutter and Divergence Analysis Using the Generalized Aeroelastic Analysis Method. Journal of Aircraft. 2008;45(3):906–915. DOI: 10.2514/1.30078
  10. Kuz’mina S.I., Ishmuratov F.Z., Popovskii V.N. et al. Analysis of dynamic response and flutter suppression system effectiveness of a long-haul aircraft in transonic flight mode. Aerospace MAI Journal. 2020;27(1):108-121. (In Russ.). DOI: 10.34759/vst-2020-1-108-121
  11. Bendiksen O. Influence of Shocks on Transonic Flutter of Flexible Wings. In: 50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference (May 04–07, 2009; Palm Springs, California). DOI: 10.2514/6.2009-2313
  12. Bendiksen O. Review of unsteady transonic aerodynamics: Theory and application. Progress in Aerospace Sciences. 2011;47(2):135-167. DOI: 10.1016/j.paerosci.2010.07.001
  13. Bragin N.N., Kovalev V.E., Skomorokhov S.I. et al. On evaluation of buffeting of a swept wing with high aspect ratio at transonic speeds. Aerospace MAI Journal. 2018;25(4):16-27. (In Russ.).
  14. Girodroux-Lavigne P. Progress in Steady/Unsteady Fluid-Structure Coupling with Navier-Stokes Equations. In: International Forum on Aeroelasticity and Structural Dynamics (IFASD 2005; June 28 – July 01, 2005; Munich, Germany).
  15. Vevek U., Timme S., Pattinson A. et al. Next-generation computational fluid dynamics capability for aircraft aeroelasticity and loads. In: 19th International Forum on Aeroelasticity and Structural Dynamics (IFASD 2022; June 13–17, 2022; Madrid, Spain). Vol. 1. p. 360–375.
  16. Ricciardi A.P. Aeroelastic Energy Analysis Using Distributed Aerodynamic Work Visualization. AIAA Journal. 2017;55(6):2113-2117. DOI: 10.2514/1.J055677
  17. Bendiksen O. Energy Approach to Flutter Suppression and Aeroelastic Control. Journal of Guidance, Control, and Dynamics. 2001;24(1):176–184. DOI: 10.2514/2.4699
  18. Ishmuratov F.Z., Kuz'mina S.I., Mosunov V.A. Computational studies of transonic flutter in the frequency and time domains. Uchenye Zapiski TsAGI. 1999;XXX(3-4):151-163. (In Russ.).
  19. Kuzmina S., Ishmuratov F., Karas O. Effects of elasticity, viscosity and boundary layer transition on aeroelasticity characteristics of laminar wings. In: 17th International Conference on Autonomic and Autonomous Systems (ICAS 2021; May 30 – June 03, 2021; Valencia, Spain). ICAS-2020-0961.
  20. Kuzmina S., Ishmuratov F., Karas O. et al. Dynamic response of an airplane elastic structure in transonic flow. In: 29th Congress of the International Council of the Aeronautical Sciences (ICAS 2014; September 07–12, 2014; St. Petersburg):140.
  21. Kuzmina S., Ishmuratov F., Karas O. Some aspects of transonic flutter of aircraft with laminar wings. In: 8th European Conference for Aeronautics and Space Sciences (EUCASS 2019; July 01-04, 2019; Madrid, Spain). DOI: 10.13009/EUCASS2019-261

mai.ru — informational site of MAI

Copyright © 1994-2025 by MAI