Numerical investigations of rotational effects on boundary-layer instabilities on the Z49 open rotor model

Abstract

Spatial linear stability analyses are performed in order to study laminar-turbulent transition in the boundary layer on the Z49 rotor, rotating in a 𝑀𝑎 ∞ = 0.75 freestream. In a rotating reference frame, terms corresponding to Coriolis and centrifugal forces appear in the linearized disturbance equations. However, the effect of these rotational terms on the stability of boundary layers is only partially understood. The rotational terms' impact on the transition mechanisms is studied by neglecting or considering rotation in the linear local stability and parabolized stability equations. The present results show that rotation hardly affects the instability characteristics of Tollmien-Schlichting waves. On the other hand, rotation destabilizes the cross-flow instabilities, but not enough to trigger cross-flow-dominated transition at the investigated operating condition.