Conceptual Aerodynamic Studies Of A Small Tailless Unmanned Air Vehicle
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Date
2014-01
Authors
Hashim, Afida
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
In principle, the tailless model configuration can be equipped with any airfoil as long
as the design is compensated with an appropriate combination of some parameter
such as aspect ratio, sweep angle and twist. This thesis presents a parametric study of
subsonic Tailless UAV conceptual design with some parameter trade off. The usages
of three types of airfoils of which are the conventional airfoil, reflex airfoil and
symmetrical airfoil in tailless configuration have been studied. The design is divided
into three cases which are case 1 (conventional airfoil), case 2 (symmetrical airfoil)
and case 3 (reflexed airfoil). All cases are designed to meet the same mission
requirement. Analyses of aerodynamic characteristics of three cases have been
carried out primarily at cruising speed (18m.s-1) using Computational Fluid Dynamic
(CFD) simulation with Spalart-Allmaras turbulence model. The fully structured mesh
is employed and grid dependency check had been carried out. The results
numerically iterated had been verified and compared to the published data. The lift
coefficient, drag coefficient, moment coefficient and lift to drag ratio are plotted,
compared and analyzed at different Reynolds number. Generally, by comparison the
results of these three cases are consistent with other tailless configurations where it
shows similarities in their aerodynamic trends. Though it is realized that
conventional airfoil have negative pitching moment, but a moderate amount of
pitching moment with proper selections of parameters such as static margin, sweep
angle, aspect ratio, and twist will enable the design to obtained a sufficient Cmo.
Thus, the sweep angle and the body shape at the center body for case 1 are varied.
The results showed a significant improvement in aerodynamic characteristic. The
pressure contours and velocity magnitude over tailless configuration were also
observed. It may achieve higher aerodynamic efficiency if some multidisciplinary
optimization is carried out.
Description
Keywords
Aerodynamic Studies , Air Vehicle