CFD Based Determination of Dynamic Stability Derivatives in Yaw for a Bird
Moelyadi M.A.a, Sachs G.b
a Aeronautics and Astronautics Department, Bandung Institute of Technology, Indonesia
b Institute of Flight Mechanics and Flight Control, Technische Universität München, Germany
Abstract
Dynamic yaw stability derivatives of a gull bird are determined using Computational Fluid Dynamics(CFD) method. Two kinds of motions are applied for calculating the dynamic yaw stability derivatives CNr and CNβ. The first one relates to a lateral translation and, separately, to a yaw rotation. The second one consists of a combined translational and rotational motion. To determine dynamic yaw stability derivatives, the simulation of an unsteady flow with a bird model showing a harmonic motion is performed. The flow solution for each time step is obtained by solving unsteady Euler equations based on a finite volume approach for a small reduced frequency. Then, an evaluation of unsteady forces and moments for one cycle is conducted using harmonic Fourier analysis. The results of the dynamic yaw stability derivatives for both simulations of the model show a good agreement. © 2007 Jilin University.
Author keywords
Dynamic yaw stability,Lateral translation,Reduced frequency,Unsteady aerodynamics,Yaw rotations
Indexed keywords
CFD,dynamic yaw stability,Fourier analysis,reduced frequency,unsteady aerodynamics