COMPUTATIONS OF AERODYNAMIC BEHAVIOUR OF RECTANGULAR WING WITH NACA653218AIRFOIL

摘要

In this research we have obtained the drag and lift coefficients, velocity, pressure and pathlines contours using CFD which can also be determined through experiments using wind tunnel testing. In experimental setup, the design model has to be placed in the test section. This process is quite laborious and surely cost more than CFD techniques cost for the same. A numerical procedure is described for determination and estimation aerodynamic properties of three dimension subsonic NACA653218airfoil rectangular wing with chord length 121 mm and semi span 330 mm. Firstly, the wing model profile, boundary conditions and meshes were all created in GAMBIT® 2.3.16 as a pre-processor. The second step in performing a CFD simulation should be to investigate the effect of the mesh size on the solution results. In present, work using multi-block unstructured grid to increase grids near wing and decrease grid far from wing to increase the uncertainty of solution and decrease the time of solution. The total number of cells in the full grid is 1500000, the volume of the smallest grid is 3.5×10-11 m3, and the volume of the largest grid is 5.799755×10-4 m3. The third step is validation of the CFD NACA65_3218airfoil rectangular wing shape model by Spalart-Allmaras turbulence model with available experimental data for the same model and operation conditions. The free stream temperature is 288.2 K, which is the same as the environmental temperature. The density of the air at the given temperature is ρ=1.225kg/m~3, the pressure is 101325 Pa and the viscosity is μ=1.7894×10~(-5) kg/m s. Reynolds number for the Pressure farfield boundary was Re=2.89×10~5. A segregated, implicit solver was utilized (ANSYS FLUENT® processor) Calculations were done for angles of attack ranging from 0 to 12°. The results show good agreement of lift coefficient with the corresponding values in the experimental and numerical models measurements. It is found maximum error by Spalart-Allmaras model is about 25%. The results show good agreement of drag coefficient with the corresponding values in the experimental and numerical models measurements. It is found maximum error by Spalart-Allmaras model is about 35%.