### Tech Briefs

FSI Analysis in Aerodynamics Applications

The traditional analysis of fluid flow around an airfoil assumes that the airfoil is rigid and hence does not change shape or position. However, using a fluid flow structure interaction analysis, the effects of the deformations of the structure are included in the calculation of the aerodynamic pressure distribution.

In this News we present a fully-coupled 2-D fluid flow structure analysis of a NACA0012 airfoil using FCBI-C elements to represent the Navier-Stokes fluid and 4-node plane strain isobeam elements to model the wing. The longitudinal flexibility of the wing is modeled using a vertical spring and a rotational spring. The analysis was carried out assuming steady state conditions, a Reynolds number of 2.1x106, and a horizontal flow direction, α = 0°. A schematic is shown in Figure 1. Figure 1. Schematic of Flexible Wing Model (including the Flexible Shell of the Wing)
used in FSI Solution

Figure 2 shows the vertical displacement and rotation of the airfoil when the wing is flexible. Figure 3 shows the ADINA calculated pressure coefficient along the airfoil surface assuming first the wing to be rigid and stationary, and then the wing to be flexible. The experimental results for α = 0° assuming a rigid wing have been taken from reference 1. In Figure 4, we show a detail of the pressure contours.

This solution example indicates that aerodynamic fluid flow structural interaction problems can be analyzed using ADINA.

For more information on ADINA FSI, please refer to our page on fluid-structure interaction. Figure 2. Rotation and Vertical Displacement of Airfoil, Displacement Magnified by 20 (Original configuration shown in red, deformed configuration in blue) Figure 3. Pressure Coefficient Cp along Airfoil Surface Figure 4. Pressure Contours Around Airfoil, Flexible Wing

 Ref. 1 Y. Li, J. Wang and P. Zhang, "Effects of Gurney Flaps on a NACA0012 Airfoil", Flow Turbulence and Combustion, 68: 27-39, 2002.