Oscillating Airfoils: Part 11. Newtonian Flow Theory and Application to Power-Law Bodies in Hypersonic Flow
A theoretical investigation of the hypersonic flow past two-dimensional airfoils oscillating with arbitrary frequency is undertaken. An unsteady Newtonian flow theory is developed which includes the contributions due to centrifugal force by considering gasdynamic theory in the limit 7 —• 1 and M^ — . The theory is valid for both sharpand blunt-nosed curved bodies, provided the shock wave remains attached at the nose. The case of airfoils supporting power-law shocks (y = x) and pitching about a pivot on its axis of symmetry is examined in light of this theory. It is seen that pivot positions ahead of h = (3mI)/9m tend to destabilize the airfoil, while those behind it have a stabilizing effect.