To serve this function, a circular cylinder is added at the leading edge of NACA0012 airfoil which can be rotated at different cylinder surface velocity ratio (Uc/U). This method includes the injection of momentum which is nothing but energy addition to the separated region to delay the detachment. As the boundary layer separation begins at the vicinity of boundary surface, it can be overcome by relatively a new approach moving surface boundary layer control (MSBLC) method. The aerodynamic coefficients like lift reduces and drag increases due to the boundary layer separation on the airfoil. Three turbulence models are introduced in this paper and make a comparative assessment for NACA0012 airfoil between the experimental results & associated model results. With the introduction of computational fluid dynamics (CFD), it becomes inevitable to know different turbulence models and how they actually acts in various flow behavior. This analysis can be used for the wing design and other aerodynamic modeling correspon ds to these airfoil. Calculations were done for constant air velocity altering only the angle of attack for every airfoil model tested. The aim of the work is to show the behavior of the airfoil at these conditions and to compare the aerodynamics characteristics between NACA 0012 & NACA 4412 such as lift co-efficient, drag co-efficient and surface pressure distribution over the airfoil surface for a specific angle of attack. The steady-state governing equations of Reynolds averaged Navier -Stokes is calculated for analyzing the characteristics of two-dimensional airfoils and the realizable k-epsilon model with Enhanced wall treatment is adopted for the turbulence closure. The two dimensional model of the airfoil and the mesh is created through ANSYS Meshing which is run in Fluent for numerical iterate solution. A commercial computational fluid dynamic (CFD) code ANSYS FLUENT based on finite volume technique is used for the calculation of aerodynamics performance. The numerical analysis of the two dimensional subsonic flow over a NACA 0012 & NACA 4412 airfoil at various angles of attack which is operating at a Reynolds number of 3×10 6 is presented. Computational results are validated with the results of NASA Langley Research Center validation cases. Moreover, it is observed that the CL/CD ratio decreases because of a rapid downward for the CL and an abrupt upward for the CD with velocity approaching the sonic velocity. From the CL (life Coefficient)/ CD (Drag Coefficient) ratio, it shows that when the Mach number (M) increases, CL increases but CD remains constant at different operating conditions. The simulation is done in ANSYS Fluent and both the k-omega and k-epsilon turbulence modeling method was used to compare the results. To show the behavior of the airfoil at these conditions is the main objective of this paper. Change in Reynolds number of fluid results in different output, hence the variation of lift & drag coefficient with the change in Reynolds number is analyzed. Different parameters used, and its effects, in analysis like domain shape, grid cells, number of nodes in meshing, various boundary conditions are surveyed. Study of a two-dimensional CFD analysis is done to investigate the effects of angle of attack and Mach number on the aerodynamic characteristics of NACA (National Advisory Committee for Aeronautics) 0012 airfoil considering turbulent flow around it.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |