*Research on Aeroelasticity Phenomenon in Aeronautical Engineering DOI: http://dx.doi.org/10.5772/intechopen.91748*

waiting time of 5 s (average of about 1000 instant values) using the Keyence pressure measurement. The standard deviation of the Keyence pressure measurement errors was within 0.001 Pa. Moreover, flutter of wing was captured with

• Time T1: time between maximum deformation and non-deformation

The wing deformation was maximum at the tip of the wing and decreased gradually into the root of the wing over time. However, the normal stress was found to have an opposite tendency in comparison with deformation. The maximum normal stress was observed at the root of the wing, while the minimum normal stress was found at the tip of the wing (**Figures 17** and **18**). It could be explained by the fixed support with fuselage at the root of the wing and free support at the tip of the wing [13]. These remarks were in well agreement with the experimental results

• Time T0: initial time when distortion did not occurred

• Time T2: time of maximum distortion

within a relative error less than 10% (**Table 7**).

The results of IBM method were analyzed at three different instants (**Figure 16**):

help of high performance camera.

**4.3 Results**

*Aerodynamics*

**Figure 17.**

**72**

*Instant normal stress—Rectangular wing.*

At T0 instant, the normal stress had important value near the wing tip. During flutter behaviors of wing, this important normal stress propagated from the tip of the wing to the root of the wing. The maximum value of the normal stress was found out at the root of the wing and at T2 instant.

With the same airfoil, the rectangular wing was found to be more distorted and have higher maximum deformation and higher maximum normal stress than the trapezoid wing. Thus, 3D-shape wing contributed significantly to the deformation of wing when aeroelasticity phenomenon occurred (**Table 7**).

With the same 3D-shape wing, the maximum deformation and maximum normal stress of NACA65A004 rectangular wing were higher than those of the rectangle supercritical wing. Meanwhile, the maximum deformation and maximum normal stress of NACA65A004 trapezoidal wing were less than those of the supercritical trapezoidal wing. It could be concluded that the 3D shape of wing played an important role in the durability of the structure (**Table 7**).

**Figure 18.** *Instant normal stress—Trapezoidal wing.*


**Table 7.** *Maximum deformation of the wing tip.*
