Numerical investigation of Active Flow Control applied to an airfoil leading edge

Objectives: The major objective of the Master Thesis proposal is to perform 2D computational study and compare the enhancement in the global aerodynamic coefficients, mainly lift and drag coefficients, for cases of with and without Active Flow Control (AFC). The focus is also on various cases of parameters of active flow control i.e, frequency of fluid ejection, jet velocity from actuator and location of slots for actuators for delaying the airfoil leading edge separation. Introduction: In the present context, the focused area is an airfoil of a regular commercial plane. The major concern while conducting experimental or numerical fluid dynamics study with the airfoils is to delay the separation of air (fluid) on both of the pressure sides on wing. The two main locations where the separation of fluid have an impact on global lift and drag coefficients include the leading edge boundary layer and the separation on the trailing edge flap.(Ciobaca & Wild, 2013). The techniques to delay the separation layer are of two major types which include Active Flow Control(AFC) and Passive Flow Control (PFC) (Jansen, 2012). The reason to choose AFC for this case is the reliability of the technique for all the future developments in various sectors like aerospace, automobile, wind energy etc (Nasa Website news 2013 [5][6]). Active Flow Control is becoming a viable tool for modifying flows for many practical applications. Active flow control can enable the design of simpler, smaller and more aerodynamically efficient structures that help reduce aircraft weight, drag, and fuel consumption. It typically refers to the use of time-dependent (often periodic) disturbances that are introduced into the flow field by the actuators. Also, AFC modifies the flow by adding energy (blowing) or by removing energy (suction). Methodology: As aforementioned, the proposed thesis focus is on computational study of the airfoil leading edge boundary layer with and without AFC. The variation of global lift and drag coefficients on varying the parameters of Active Flow Control like frequency, jet velocity and location of slots. The research conducted by (Burt Gunther et.al 2010) on AFC for airfoil flap will be used as guidance for conducting the similar test cases for Leading Edge AFC. The preliminary results from the computational model will be compared with the existing experimental results obtained at TU Braunschweig and DLR, Germany (Ciobaca & Wild, 2013) to check the accuracy and reliability of the numerical simulation results in order to further contribute to the existing state of the art results. To develop the computational model, the NACA2412 is chosen. The initial focus is on incompressible flow conditions by choosing the appropriate turbulence model and other numerical methods for solving Unsteady Reynolds Averaged Navier Stokes (URANS) Equations. Depending upon the accuracy of the results when compared with the experimental results, there will always be a flexibility to improvise the results using more computationally intensive numerical methods. The major software tools that will be used include a combination of ANSYS Fluent and OpenFOAM. References: 1. Ciobaca, V., & Wild, J. (2013). An Overview of Recent DLR Contributions on Active Flow-Separation Control Studies for High- Lift Configurations, (6), 1-12. 2. Generators, V., & Jansen, D. P. (2012). Passive Flow Separation Control on an Airfoil-Flap Model, (August). 3. Nagib, P. H. M., Kiedaisch, J. W., Wygnanski, P. I. J., Stalker, A. D., Wood, T., & Mcveigh, M. A. (n.d.). First-In- Flight Full-Scale Application of Active Flow Control : The XV-15 Tiltrotor Download Reduction