P92 and 15CH2NMFA Steels – A Comparison of Fatigue Characteristics obtained on standard and miniature test specimens

Volák, Josef; Bunda, Zbyněk; Mentl, V.

doi:10.1016/j.proeng.2018.02.078

Cited by 1 publication

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“…is requires studying the aerodynamic characteristics of small UAVs with low Reynolds numbers. Although increasing the thickness of the airfoil can improve the rigidity of the rotor structure, Josef et al proposed a small Reynolds number airfoil with a downward concave structure [5]. Gawron et al uses a numerical statistical method based on the three-dimensional fixed and non-decompressible orifice calculation formula to calculate the aerodynamic performance of the airfoil with a Reynolds number of 40,000 to 100,000 and compare it with the traditional arc thin airfoil [6].…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic and Vibration Characteristics of the Micro-Octocopter at Low Reynolds Number

Zou

Ling

Zhai

2021

Mobile Information Systems

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With the development of flight technology, the need for stable aerodynamic and vibration performance of the aircraft in the civil and military fields has gradually increased. In this case, the requirements for aerodynamic and vibration characteristics of the aircraft have also been strengthened. The existing four-rotor aircraft carries limited airborne equipment and payload, while the current eight-rotor aircraft adopts a plane layout. The size of the propeller is generally fixed, including the load capacity. The upper and lower tower layout analyzed in this paper can effectively solve the problems of insufficient four-axis load and unstable aerodynamic and vibration performance of the existing eight-axis aircraft. This paper takes the miniature octorotor as the research object and studies the aerodynamic characteristics of the miniature octorotor at different low Reynolds numbers, different air pressures and thicknesses, and the lift coefficient and lift-to-drag ratio, as well as the vibration under different elastic moduli and air pressure characteristics. The research algorithm adopted in this paper is the numerical method of fluid-solid cohesion and the control equation of flow field analysis. The research results show that, with the increase in the Reynolds number within a certain range, the aerodynamic characteristics of the miniature octorotor gradually become better. When the elastic modulus is 2.5 E, the aircraft’s specific performance is that the lift increases, the critical angle of attack increases, the drag decreases, the lift-to-drag ratio increases significantly, and the angle of attack decreases. However, the transition position of the flow around the airfoil surface is getting closer to the leading edge, and its state is more likely to transition from laminar flow to turbulent flow. When the unidirectional carbon fiber-reinforced thickness is 0.2 mm and the thin arc-shaped airfoil with the convex structure has a uniform thickness of 2.5% and a uniform curvature of 4.5%, the aerodynamic and vibration characteristics of the octorotor aircraft are most beneficial to flight.

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Section: Introductionmentioning

confidence: 99%