Behailu Mamo (Mr.)Anania Mulugeta2023-12-052023-12-052023-10http://etd.aau.edu.et/handle/123456789/231Nowadays, agricultural aerial vehicles are being broadly applied at the focal point of the farming development. Where crop damage rate raised by 1 % without mechanization at sown area, wind was one of the negative factors to utilization of UAVs for this purpose. This research was directed with the objective of characterizing three quadcopter UAV models and numerical CFD analysis of the models to study the aerodynamic behavior and stability analysis for precise agricultural sowing application. Implementing the finite volumetric analysis using Rynolds Average Navier Stock method, Ansys was used to simulate the fluid flow simulation along the identified horizontal and downwash wind fields for wind speed ranges of 0.3 m/s, 0.6 m/s, 0.9 m/s, and 1.2 m/s, 2.5 m/s considered in case of altitude increase. The objective parameters were velocity magnitude, pressure distribution, drag force, drag coefficient and moment coefficients. Findings of drag coefficients of rectangular solid, crossed helical, mobius ring all with elliptical hopper were 0.274, 1.29, 2.5 respectively, for downwash flow and 1.5, 2.6, 3.7 respectively, for horizontal flow during 2.5 m/s wind flow. Instability in terms of impulse response were more pronounced on mobius ring with elliptical hopper at 2.5 m/s wind gust while rectangular solid with elliptical hopper had revealed a desirable minimum drag coefficient and stability condition on moment coefficients for both flow cases as compared to the other models. In conclusion, shape effects had been observed on the variation of drag and stability values particularly on mobius ring with elliptical hopperen-USThesis