Yu Hu

The ducted propeller is superior to the open propeller in hovering efficiency. However, the overall system efficiency of a ducted propeller is reduced due to its heavy structure. If the weight penalty is taken into account, will the ducted propeller still be superior to an open propeller? And in this scenario, how will a ducted propeller with bette...

In recent years, a lot of research work has been carried out on the cycloidal rotors. However, it lacks thorough understanding about the effects of the blade platform shape on the hover efficiency of the cycloidal rotor, and the knowledge of how to design the platform shape of the blades. This paper presents a numerical simulation model based on Un...

The design of ducted fan was primarily based on parametric analysis and the existing optimization design studies mainly focus on either the rotor or the duct alone. However, the interactions between the rotor and duct remarkably affects the performance of the ducted fan. Therefore, it has been expected that an integrated optimization such the rotor...

Purpose This paper aims to investigate the impact of aerofoil camber on the performance of micro-air-vehicle-scale cycloidal propellers. Design/methodology/approach First, experiments were conducted to validate the numerical methodology. After that, three turbulent models were compared to select the most accurate one. Then, 2D numerical simulati...

Purpose This paper aims to investigate the mechanisms lying behind the cycloidal rotor under hovering status. Design/methodology/approach Experiments were conducted to validate the numerical simulation results. The simulations were based on unsteady Reynolds-averaged Navier–Stokes (URANS) equations solver and the sliding mesh technique was used...

Cycloidal rotor is a rotor whose blades pitch around the pitching axis and revolve around the rotor shaft that is parallel to blade. It can generate omni-directional thrust with high efficiency. In this paper, the numerical simulation models were validated by the wind tunnel experiments. Then physics of the cycloidal rotor in forward flight was stu...

An effective unsteady aerodynamic-optimization method of airfoil for cycloidal propellers is developed. Firstly, the class-function/shape-function transformation parameterization method is adopted to describe the airfoil profile with different geometrical parameters. Secondly, the sample points in the design space are selected using the optimal Lat...

A new unsteady three-dimensional aerodynamic performance prediction approach is established to achieve fast and accurate prediction of the unsteady aerodynamics of cycloidal propellers. This model is developed by the coupling of momentum theory, lifting-line method, free wake model, and the Leishman–Beddoes semi-empirical dynamic stall model. The o...

The cycloidal propellers for micro aerial vehicle scale cyclocopter in hovering status were studied in this paper based on the URANs solver using 2D, 2.5D, 3D half blade and 3D full blade model. The results from all numerical models were validated with the experimental results. It was found that 2.5D model cannot produce more accurate results than...

The cycloidal propeller for a Micro-Aerial Vehicle (MAV)-scale cyclogyro in hover was studied using a 2D Reynolds-averaged Navier-Stokes equations solver. The effects of the blade dynamic stall, parallel Blade Vortex Interaction (BVI), inflow variation and flow curvature were discussed, based on the results of numerical simulation. The results from...

In this note, the equivalence between differential and integral pseudospectral methods is justified from the distinctive perspective of Birkhoff interpolation for collocation at the Jacobi–Gauss and flipped Jacobi–Gauss–Radau points. Furthermore, an exact, efficient, and stable approach is presented for computing the associated pseudospectral diffe...

Flight performance and longitudinal static stability are two contradictory requirements for aircraft. This is especially true for a tailless configuration, whose flight performance is traded for static stability. A new tailless gull wing configuration with propeller thrust trimming is proposed in this paper. It is expected that the propeller thrust...

For small electric-powered unmanned aerial vehicles (EPUAV), endurance performance largely depends on propulsion system. To improve EPUAV endurance, the electric-powered propulsion system was designed optimally. Meanwhile EPUAV endurance formula was presented. Based on vortex theory, a small screw propeller was designed optimally using genetic algo...

The aerodynamics of a cycloidal propeller operating in hovering flight is systematically studied using numerical method. By solving the time-dependent incompressible Navier-Stokes equations and using a dynamic mesh technique, the complex unsteady flow field around the cycloidal propeller and the time-varying aerodynamic forces are investigated. The...

The numerical simulations for cycloidal propellers based on five aerofoils with different thickness are presented in this paper. The CFD simulation is based on sliding mesh and URANS. The results of CFD simulation indicates that all test cases share similar flow pattern. There are leading edge vortex and trailing-edge vortex due to blade dynamic st...

The two-dimensional cycloidal propeller model was simplified from a cycloidal propeller aircraft developed by Northwestern Polytechnical University. The dynamic mesh method of spring-based smoothing and local remeshing was adopted to achieve blades' rotating and pitching movement in the unsteady numerical simulation. The influence of the key design...

A prototype of a cycloidal propulsion vehicle which is developed by Northwestern Polytechnical University is chosen as the research model of this paper. To investigate the unsteady aerodynamics of the cycloidal propeller, numerical analysis is conducted on a two-dimensional simplified cycloidal propeller model. The dual-time method is used for unst...

The performance of tailless aircrafts is sensitive to the design parameters such as wing twist angle, elevon deflection and center of gravity. Therefore the robust optimization algorithms can be a good tool to assist the designers to find the design that is less sensitive to the wing shape deviation due to errors from theoretical modeling, design c...

The existing aircraft configuration cannot satisfy the requirements for the longitudinal stability and flight performance of a static and stable fixed-wing aircraft. This is especially true for a flying wing aircraft, whose flight performance deteriorates in maintaining its static stability. Hence, we propose a new aerodynamic configuration that us...

A numerical study with dynamic mesh technique has been conducted on a cyclorotor operating at Reynolds numbers about 20,000~90,000. The varying total thrust of cyclorotor , the force on blade during revolution and the aerodynamic characteristics of the unsteady flow field around cyclorotor and blade airfoil are investigated in detail. The instantan...

The numerical simulations for cycloidal propellers based on five airfoils with different thickness are presented in this paper. The CFD simulation is based on sliding mesh and URANS. The result of CFD simulation indicates that all test cases share similar flow pattern. There are leading edge vortex and trailing edge vortex due to blade dynamic stal...

Cycloidal propeller is a new device composed of two or more blades, which can provide thrust in all directions. It has become a research hotspot in the field of aeronautics research in foreign countries recent years. In this paper, domestic and foreign progress of research on the aerodynamics performance of cycloidal propeller is summarized, which...

For static stable fixed wing aircraft, there are contradictory requirements from the flight performance and the longitudinal stability. This is true especially for flying wing aircraft. The flight performance is deteriorated in order to maintain the static stability of the aircraft. To solve this problem, a new aerodynamics configuration which invo...