divergence-speedlisted

# Static Aeroelastic Divergence (aerodynamics/aeroelasticity/divergence-speed) Use when the task is the static aeroelastic divergence condition of a lifting surface: the divergence dynamic pressure from the torsional stiffness and the aerodynamic center to shear center offset, the divergence speed, and the divergence margin against the design dive speed. ## Domain quick reference - Static divergence: the lift acts at the aerodynamic center, ahead of the shear center (elastic axis). Its torsional moment about the shear center twists the surface nose-up, which raises the local angle of attack and the lift. The destabilizing moment grows with the dynamic pressure; at the divergence dynamic pressure it overcomes the torsional stiffness and the twist grows without bound. - Divergence dynamic pressure: q_div = k_theta / (S * c * C_Lalpha * e), where k_theta is the torsional stiffness about the shear center axis (N m per rad; for a beam model the product G * K_theta of the shear modulus and the torsion constant), S the reference area (m^2), c the chord (m), C_Lalpha the lift curve slope per radian, and e the offset ratio, the aerodynamic-center-to-shear-center distance divided by the chord, positive when the aerodynamic center lies ahead of the shear center. Worked example, k_theta = 40000 N m per rad, S = 16 m^2 (2 m chord over an 8 m strip), c = 2 m, C_Lalpha = 5.0 per radian, e = 0.2 (aerodynamic center at 25 percent chord, shear center at 45 perc