01. Experimental/Computational Fluid Dynamics

Quetzalcoatlus was one of the world's largest pterosaurs, and its wingspan and body weight are estimated at 10 m and 70-270 kg, respectively. However, flight capabilities of Quetzalcoatlus remains unclear. In this study, to evaluate the flight capabilities, a 3D fluid analysis around the wings of 3D model of Quetzalcoatlus is conducted with an angle of attack as a parameter. Before the evaluation of the flight capabilities of Quetzalcoatlus, to optimize the analysis conditions, a two-dimensional steady-state fluid analysis is performed for an aircraft wing type of NACA4412, whose aerodynamic characteristics are already known. In this analysis, the flow field around the wing is assumed to be a laminar boundary layer. The governing equations are the continuity equation and Navier-Stokes equation. The wind speed is 5 m/s and the Re number is 106 at the end of the wing. To discuss the appropriate mesh system, this analysis adopts an unstructured polyhedral mesh and a structured mesh with cut-cell method. The analysis results show that when the angle of attack is within 5°, the lift coefficients estimated for both meshes have only 1% relative error compared to the reference data. In contrast, at an angle of attack of 10°, the relative errors in the polyhedral mesh and the structural mesh are 3% and 7%, respectively. Therefore, the lift coefficient can be predicted with high accuracy by using the polyhedral mesh even at a high-angles-of-attack. The analysis results of flight capabilities of Quetzalcoatlus will be presented on the day of the ISTP conference.