Modeling effects of membrane tension on dynamic stall for thin membrane wings

An approach for predicting time varying aerodynamic loads on a pitching membrane wing due to rotational pitching and steady airflow is presented. The proposed model utilizes potential flow theory for a thin cambered airfoil with finite span, combined with a linearized representation of the membrane physics to predict lift under static conditions. Quasi-steady rotational effects and added mass effects are considered in a classic potential flow approach, modified for a membrane airfoil. A high-fidelity numerical model has been developed as well, coupling a viscous fluid solver and a non-linear membrane structural model, to predict the configuration of the system under static and unsteady loads. Moving Least Squares are used to map the structural and fluid interface kinematics and loads during the fluid-structure co-simulation. The static and dynamic lift predictions of the two models are compared to wind tunnel data, and show reasonable accuracy over a wide range of flow conditions, reduced frequency, and membrane pretension.