Aerodynamic models for cycloidal rotor analysis

Gagnon, Louis; Morandini, Marco; Quaranta, Giuseppe; Muscarello, Vincenzo; Masarati, Pierangelo

doi:10.1108/aeat-02-2015-0047

Cited by 12 publications

(8 citation statements)

References 15 publications

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“…The wide range of aerospace applications for cycloidal rotors has been further demonstrated by other researchers such as Xisto et al (3,4,18) , which formed as part of the extensive Cycloidal Rotor Optimised for Propulsion (CROP) project, led by Pascoa (19) . The CROP report, published in 2015, outlined in significant detail the numerical and experimental research conducted on cycloidal rotor propulsion for a wide range of potential applications.…”

Section: July 2017mentioning

confidence: 90%

“…The CROP report, published in 2015, outlined in significant detail the numerical and experimental research conducted on cycloidal rotor propulsion for a wide range of potential applications. Gagnon (4) contributed to this report by developing a simplified analytical model that can be resolved analytically to assess the cycloidal rotor’s performance as an anti-torque device for a compound helicopter. A visualisation of the proposed helicopter design concept is shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

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Improving the aerodynamic performance of a cycloidal rotor through active compliant morphing

2017

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Cycloidal rotors are a novel form of propulsion system that can be adapted to various forms of transport such as air and marine vehicles, with a geometrical design differing significantly from the conventional screw propeller. Research on cycloidal rotor design began in the early 1930s and has developed throughout the years to the point where such devices now operate as propulsion systems for various aerospace applications such as micro air vehicles, unmanned air vehicles and compound helicopters. The majority of research conducted on the cycloidal rotor’s aerodynamic performance have not assessed mitigating the dynamic stall effect, which can have a negative impact on the rotor performance when the blades operate in the rotor retreating side. A solution has been proposed to mitigate the dynamic stall effect through employment of active, compliant leading-edge morphing. A review of the current state of the art in this area is presented. A two-dimensional, implicit unsteady numerical analysis was conducted using the commercial computational fluid dynamics software package STAR CCM+, on a two-bladed cycloidal rotor. An overset mesh technique, otherwise known as a chimera mesh, was used to apply complex transient motions to the simulations. Active, compliant leading-edge morphing is applied to an oscillating NACA 0015 aerofoil to attempt to mitigate the dynamic stall whilst maintaining the positive dynamic lift coefficient (Cl) contributions. It was verified that by applying a pulsed input leading-edge rotational morphing schedule, the leading-edge vortex does not fully form and the large flow separation is prevented. Further work in this investigation will focus on coupling the active, leading-edge motion to the cycloidal rotor model with the aim to maximise aerodynamic performance.

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Section: July 2017mentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Improving the aerodynamic performance of a cycloidal rotor through active compliant morphing

2017

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“…The rotor model is initiated by enhancing a simulation from a previous project [11,12], which had been validated against experimental data [30] for a larger rotor without endplates. That prior CFD simulation had been shown to yield more accurate quantitative results than its analogous 2D version.…”

Section: Rotor Modelmentioning

confidence: 99%

Open-Source 3D CFD of a Quadrotor Cyclogyro Aircraft

Gagnon

Quaranta

Schwaiger³

2019

OpenFOAM®

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This chapter provides a detailed method for building an unsteady 3D CFD model with multiple embedded and adjacent rotating geometries. This is done relying solely on open source software from the OpenFOAM package. An emphasis is placed on interface meshing and domain decomposition for parallel solutions. The purpose of the model is the aerodynamic analysis of a quadrotor cyclogyro. The challenging features of this aircraft consist of a series of pairwise counter-rotating rotors, each consisting of blades that oscillate by roughly 90 • about their own pivot point. The task is complicated by the presence of solid features in the vicinity of the rotating parts. Adequate mesh tuning is required to properly decompose the domain, which has two levels of sliding interfaces. The favored decomposition methods are either to simply divide the domain along the vertical and longitudinal axes or to manually create sets of cell faces that are designated to be held in a single processor domain. The model is validated with wind tunnel data from a past and finished project, for a series of flight velocities. It agrees with the experiment in regard to the magnitude of vertical forces, but only in regard to the trend for longitudinal forces. Comparison of past wind tunnel video footage and CFD field snapshots validates the features of the flow. The model uses the laminar Euler equations and gives a nearly linear speedup on up to 4 processors, requiring one day to attain periodic stability.

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“…This assumption is not exactly true because, when producing forward thrust, the blades will be subjected to an inflow which reduces the angle of attack at the position of maximum blade pitching angle. A further analysis may be conducted by using the equations presented in a related work [29] where the equation of the angle of attack is given. Other explanations for the differences between the radius increase, measured by the two models, are that the multibody model uses tabular drag and lift data; computes the exact lift coefficient; calculates the resulting inflow; and, accounts for the flexibility-induced delay in the response.…”

Section: E Influence Of Stiffnessmentioning

confidence: 99%

“…18(c) and 18(d), where a non-dimensional representation is used to better show the differences between the different strengths and gradients. The non-dimensional moment is defined as, 10 7 M y (rpm) −1.78 (29) It is seen that the gust gradient and velocity influences on moment and shear stress are smaller, but larger in proportion, at low angular velocities. A smaller gradient and a higher velocity both increase the moment.…”

Section: F Wind Gustsmentioning

confidence: 99%