Response of Spring-Mounted Wing System to Increased Airflow Using Various Spring Constants

The fluid–structure interaction of a pivoted rigid wing connected to a spring and subjected to laminar airflow is studied using a numerical approach. Fluid–structure interactions can, on the one hand, lead to undesirable aerodynamic behaviour or, in extreme cases, to structural failure. On the other hand, improved aerodynamic performance can be achieved if a controlled application within certain limitations is provided. Spring-mounted wings can be set up to decrease their incidence as flow speed increases, therefore decreasing its drag and lift when compared to a non-flexible wing. The spring mounted wing concept has multiple applications. In the aerospace sector, the concept could be used on control surfaces to mitigate the effects of gusts. The use of the concept will result in lower lift and drag coefficients at the relatively higher flow speed found within a gust, thus mitigating the increase in lift and drag which would otherwise result from the increased relative speed. The opposite effect occurs at a lower flow speed resulting in a more stable airframe overall. In the maritime sector, the concept can be applied to hydrofoils or propellers to mitigate against cavitation and hence improve performance and fatigue life. In the automotive sector, the concept can be used to reduce fuel consumption resulting in extended range or it can be used to achieve a higher top speed, whilst maintaining downforce and grip at lower speeds for cornering. The general operation of the concept has previously been verified at low angles in the pre-stall region in the form of a theoretical estimation using finite and infinite wings. This paper provides a numerical solution of the same problem, but reports the effect of using varying spring stiffnesses. Stable results were found at all angles tested. An analysis is reported concerning how changing the spring torque settings effects the performance.