Análise numérica das características aerodinâmicas de uma asa de baixo alongamento com propulsão distribuída

Abstract

Distributed propulsion concept expands the boundaries of aircraft designs, therefore, the study of aerodynamic effects due to propulsion/wing interaction is extremely important for the elaboration of a wing as efficient as possible in the aerodynamic and structural scope. The objective of the present research is to analyze the effects of the distributed propulsion concept, in tractor configuration, on the flow field around a low-aspect-ratio wing and evaluating the changes in aerodynamic characteristics. Numerical methods based in Reynolds-Averaged Navier-Stokes equations were used, including the k-ω SST turbulence model and an actuator disk model based on blade element theory that represent the propulsion; when validated through experimental data found in literature, numerical methods showed good representation of the flow physics, especially in wing regions directly affected by the propulsion flow-field. Results demonstrate that the flow induced by the distributed propulsion significantly alters the flow field around the wing and consequently alters the aerodynamic characteristics of the wing. When comparing the distributed propulsion concept with a base wing without interaction effects, it was observed that: i) there was a displacement of the lift curve, changing the lift to a certain angle of attack; ii) the change in lift curve slope and iii) increase the maximum lift coefficient value. In addition, the combinations of the propeller rotation directions can considerably modify the pressure, lift and shear stress distributions on the wing that being able to change the regions where the flow begins to separate from the wing surface and changing the load distributions. When considered in a cruise flight, the wing showed an increase in the aerodynamic efficiency which indicates drag reduction due to propulsion/wing interaction.