Computational investigation of perpendicular blade-vortex interaction

Abstract Blade-vortex interaction is a complex flow phenomenon where a rotor blade encounters a vortex flow shed by a preceding blade, drastically changing the aerodynamics of the blade and the structure of the vortex. Investigation of intricate flow features in vortex interactions with aerodynamic surfaces is crucial since this phenomenon influences the aerodynamic performance. Although such flows exhibit unsteady features, steady-state analyses are performed in this investigation with the aim of reducing the computational expense since they can still offer sufficient resolution if a highly refined grid is used. This study investigates the flow field under the influence of perpendicular blade-vortex interaction (BVI) by using Reynolds-averaged Navier-Stokes (RANS) equations, where the vortices are formed by a vortex generator located upstream of an airfoil. The angle of attack of the vortex generator is incrementally varied over a range of ±10° while the downstream airfoil is kept fixed at the given position and orientation. Results demonstrate how the vorticity field at different locations throughout the domain and the skin friction and pressure coefficients around the airfoil surface are affected by different angle of attack values of the upstream vortex generator, bringing more insight into the influence of vortex flow behavior on the flow field around an aerodynamic surface. The angle of attack of the vortex generator is found to be strongly dictating the vortex strength, trajectory, and rotational direction of vortices, which leads to distinct attachment and separation patterns on the airfoil surfaces. A pronounced effect of the impacting vortex on the airfoil surface is observed on its skin friction and pressure distributions resulting in observable variations along the airfoil span, which is further examined via a follow-up aerodynamic performance analysis.