Development and validation of a facility to study the unsteady aerodynamic interactions between lifting surfaces

From the interactions between tandem insect wings to that between the rotors in multi-rotor aerial vehicles, unsteady aerodynamic interference between multiple lifting bodies dictates the efficiency and stability of these systems. While studies have focused on investigating the unsteady aerodynamics of multiple lifting bodies translating in the same direction, research on unsteady interactions between two lifting surfaces translating in opposite directions has been scarce. As such, this study details the development and validation of a towing tank facility, enabling the study of unsteady interactions between two moving lifting surfaces. The facility consists of a translation system for wings with chord length c = 0.036m and a translation length of 24c. The wings are equipped with strain gauge loadcells to quantify the blade airloads, and flow visualization is employed to understand the underlying flow physics. For the validation of the facility, single-wing experiments are conducted, and the results are compared with the literature. Initially, the influence of acceleration on the steady-state characteristics of a single wing is investigated. The steady-state characteristics of the wing airloads are then analyzed across a range of Reynolds number conditions.