Prediction of Onset of Laminar to Turbulent Transition Point for the flow around an Airfoil with NumericalSolution of the Orr-Sommerfeld Equationusing Numerical Profiles

Document Type : Research Paper

Authors

Abstract

The onset of laminar to turbulent transition point over airfoils in 2D flows has been determined. For this purpose, the hydrodynamic stability analysis of fluid flow is required which has been done by solving the Orr-Sommerfeld equation.An efficient and accurate finite difference method has been utilized to solve the Orr-Sommerfeld equation.The velocity profiles and their derivatives within the boundary layer are required at all sections in streamwise direction for solving the Orr-Sommerfeld equation which are obtained by a flow solver. A CFD code using an implicit TVD scheme was used to solve 2D Navier-Stokes equations.To determine the onset of transition location from laminar to turbulent regime, the eN method was used. This method based on the linear stability theory uses the eigenvalues of Orr-Sommerfeld equation for determining the amplification rates of disturbance waves. The solution to the Orr-Sommerfeld equation was in good agreement with the other numerical and analytical solutions thanks to the efficient algorithm used. Moreover, extracting the velocity profiles from viscous flow solution leads in the satisfying prediction of the transition point for the flow around a NACA0012 airfoil.

[1] White, F.M., Viscous Fluid Flow, McGraw Hill Press, 1991.
[2] Drazin, P.G., and Reid, W.H., Hydrodynamic Stability, Cambridge University Press, 1981.
[3] Cebeci, T., Shao, J.P., Kafyeke, F., and Laurendeau, E., Computational Fluid Dynamics for Engineers, Horizons Publishing, California, 2005.
[4] Jordinson, R., “The Flat Plate Boundary Layer, Part1: Numerical Integration of the Orr-Sommerfeld Equation”, Journal of Fluid Mechanic, Vol. 43, 1970, pp. 801-811.
[5] Orszag, S.A., “Accurate solution of the Orr-Sommerfeld stability equation”, Journal of Fluid Mechanic, Vol. 50, 1971, pp. 689-703.
[6] Ng, B.S., and Reid, W.H., “On the Numerical Solution of the Orr-Sommerfeld Problem: Asymptotic Initial Conditions for Shooting Methods”, Journal of Computational Physics, Vol. 38, 1980, pp. 275-293.
[7] Marusic, I., Tang, B., Rumchik, C., and Chinniah, R., “Stability Analysis of a Cylinder Wake”, University of Minnesota, Pub.AEM 8211, 2001.
[8] Georgievskii, D.V., Muller, W.H., and Abali, B.E., “Eigenvalue Problems for the Generalized Orr-Sommerfeld Equation in the Theory of Hydrodynamic Stability”, Doklady Physics, Vol. 56, No. 9, 2011, pp. 494-497.
[9] Van Ingen, J.L., “The eN method for transition prediction, Historical review of work at TU Delft”, 38th AIAA Fluid Dynamics Conference and Exhibit, Washington, 2008.
[10] Stock, H.W., and Haase, W., “Feasibility Study of eN Transition Prediction in Navier–Stokes Methods for Airfoils”, AIAA Journal, Vol. 37, No. 10, 1999, pp. 1187-96.
[11] Lian, Y., and Shyy, W., “Laminar-Turbulent Transition of A Low Reynolds Number Rigid or Flexible Airfoil”, AIAA Journal, Vol. 45, No. 7, 2007, pp. 1501-13.
[12] Arumugam, S., and Durairaj, S., “Prediction of Laminar to Turbulent flow over a sweptback wing”, 2nd International Conference on Mechanical and Aerospace Engineering, ICMAE, Bangkok, 2011.
[13] Boutilier, M.S.H., and Yarusevych, S., “Parametric Study of Separation and Transition Characteristics over an Airfoil at Low Reynolds Numbers”, Expirement in Fluids, Vol. 52, 2012, pp. 1491–1506.
[14] Sedaghat, A., A Finite Volume TVD Approach to Transonic Flow Computation, PHD Thesis, University of Manchester, England, 1997.
[15] Yee, H.C., “Construction of Explicit and Implicit Symmetric TVD Schemes and Their Applications”, Journal of Computational physics, Vol. 68, 1987, pp. 151-179.
[16] Stock, H.W., “Airfoil Validation Using Coupled Navier–Stokes and eN Transition Prediction Methods”,Journal of Aircraft, Vol. 39, No. 1, 2002, pp. 51-58. 2012.
[17] Lee, J.D., and Jamesony, A., “NLF Airfoil and Wing Design by Adjoint Method and Automatic Transition Prediction”, 27th AIAA Applied Aerodynamics Conference, Texas, 2009.
[18] Holst, T.L., “Viscous Transonic Airfoil Workshop Compendium of Results”, Journal of Aircraft, Vol. 25, No. 12, 1988, pp. 1073-87.
[19] Gregory, N., and O’Reilly, C.L., “Low-Speed Aerodynamic Characteristics of NACA0012 Airfoil Section, Including the Effects of Upper-Surface Roughness Simulating Hoar Frost”, TR, NPL Aero Rept. 1308, Middlesex, England, 1970.