A Quasi-Steady Lifting Line Theory for Insect-Like Hovering Flight

Area of Science:

• Aerodynamics
• Bio-inspired Engineering
• Fluid Mechanics

Background:

• Insect flight relies on complex wing aerodynamics for hovering.
• Accurate aerodynamic force estimation is crucial for understanding insect flight mechanics.

Purpose of the Study:

• To develop a novel lifting line formulation for quasi-steady aerodynamic evaluation of insect wings in hovering flight.
• To quantify the contributions of induced and profile drag in insect-like wings during hover.

Main Methods:

• Introduced an equivalent angle of attack to capture non-linear aerodynamics at high angles of attack.
• Incorporated non-ideal induced effects and low Reynolds number effects into the lifting line theory.
• Validated the model against revolving wing experiments and high-fidelity computational fluid dynamics (CFD) simulations.

Main Results:

• The model accurately predicts aerodynamic forces using only geometry and kinematics.
• Mean lift to weight ratio predictions showed an average error of 4% compared to CFD for eight insect cases.
• Induced drag accounted for 22% of total drag on average (mean cycle values).

Conclusions:

• The novel lifting line formulation provides accurate aerodynamic evaluation for insect-like wings in hover.
• The model significantly improves upon unmodified linear lifting line approaches, reducing overestimation of lift force.
• This work offers quantitative insights into the drag components crucial for insect flight.