The Use of Gramian Matrices for Aeroelastic Stability Analysis

Table 1

Physical and geometric properties of the 2D airfoil.

Aerodynamic semichord	𝑏=0.15 m
Airfoil mass	𝑀=5.0 kg
Plunge frequency	𝜔ℎ=3.0 Hz
Pitch frequency	𝜔𝜃=4.5 Hz
Control surface rotation frequency	𝜔𝛽=12 Hz
Air density	𝜌=1.2895 kg/m^3
Lag parameters (Roger's method)	𝛽1=0.2𝛽2=1.2𝛽3=1.6𝛽4=1.8
Reduced frequencies	0.1≤𝑘≤2.0;Δ𝑘=0.1
Figure 2	𝑎=−0.40
Figure 2	𝑐=0.60
Distance between c.e. to c.g.	𝑥𝜃=0.20
Distance between c.e. to c.g. (flap)	𝑥𝛽=0.0125
Radius of gyration of the flap referred to 𝑎	𝑟𝛽=(6.25×10^−3)^1/2
Radius of gyration of the airfoil referred to 𝑎	𝑟𝜃=√0.25
Elastic center	c.e.
Center of gravity	c.g.