Numerical Investigation of the Rotor-Rotor Aerodynamic Interaction for eVTOL Aircraft Configurations

The rotor-rotor aerodynamic interaction is one of the key phenomena that characterise the flow and the performance of most of the new urban air mobility vehicles (eVTOLs) developed in the recent years. The present article describes a numerical activity that aimed to the systematic study of the rotor-rotor aerodynamic interaction with application to the flight conditions typical of eVTOL aircraft. The activity considers the use of a novel mid-fidelity aerodynamic solver based on vortex particle method. In particular, numerical simulations were performed when considering two propellers both in side-by-side and tandem configuration with different separation distances. The results of numerical simulations showed a slight reduction of the propellers performance in side-by-side configuration, while a remarkable loss of thrust in the order of 40% and a reduction of about 20% of the propulsive efficiency were found in tandem configuration, particularly when the propeller disks are completely overlapped. Moreover, the flow field analysis enabled providing a detailed insight regarding the flow physics involved in such aerodynamic interactions.

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Unsteady loads for coaxial rotors in forward flight computed using a vortex particle method

The Aeronautical Journal ◽

10.1017/aer.2018.8 ◽

2018 ◽

Vol 122 (1251) ◽

pp. 693-714 ◽

Cited By ~ 13

Author(s):

J. Tan ◽

Y. Sun ◽

G. N. Barakos

Keyword(s):

Flow Model ◽

Particle Method ◽

Reversed Flow ◽

Aerodynamic Loads ◽

Unsteady Aerodynamic ◽

Vortex Particle Method ◽

Coaxial Rotor ◽

Aerodynamic Interaction ◽

Coaxial Rotors ◽

Vortex Particle

ABSTRACTRecent advances in coaxial rotor design have shown benefits of this configuration. Nevertheless, issues related to rotor-head drag, aerodynamic performance, wake interference, and vibration should also be considered. Simulating the unsteady aerodynamic loads for a coaxial rotor, including the aerodynamic interactions between rotors and rotor blades, is an essential part of analysing their vibration characteristics. In this article, an unsteady aerodynamic analysis based on a vortex particle method is presented. In this method, a reversed-flow model for the retreating side of the coaxial rotor is proposed based on an unsteady panel technique. To account for reversed flow, shedding a vortex from the leading edge is used rather than from the trailing edge. Moreover, vortex-blade aerodynamic interactions are accounted for. The model considers the unsteady pressure term induced on a blade by tip vortices of other blades, and thus accounts for the aerodynamic interaction between the rotors and its contribution to the unsteady airloads. Coupling the reversed-flow model and the vortex-blade aerodynamic interaction model with the viscous vortex-particle method is used to simulate the complex wake of the coaxial rotor. The unsteady aerodynamic loads on the X2 coaxial rotor are simulated in forward flight, and compared with the results of PRASADUM (Parallelized Rotorcraft Analysis for Simulation And Design, developed at the University of Maryland) and CFD/CSD computations with the OVERFLOW and the CREATE-AV Helios tools. The results of the present method agree with the results of the CFD/CSD method, and compare to it better than the PRASADUM solutions. Furthermore, the influence of the aerodynamic interaction between the coaxial rotors on the unsteady airloads, frequency, wake structure, induced flow, and force distributions are analysed. Additionally, the results are also compared against computations for a single-rotor case, simulated at similar conditions as the coaxial rotor. It is shown that the effect of tip vortex interaction plays a significant role in unsteady airloads of coaxial rotors at low speeds, while the rotor blade passing effect is obviously strengthened at high-speed.

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Coupled Viscous Vortex Particle Method and Unstructured Computational Fluid Dynamics Solver for Rotorcraft Aerodynamic Interaction Analysis

49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition ◽

10.2514/6.2011-1121 ◽

2011 ◽

Cited By ~ 1

Author(s):

Jinggen Zhao ◽

Chengjian He ◽

Lucy Zhang ◽

Hongwu Zhao ◽

Patrick Hu

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Interaction Analysis ◽

Particle Method ◽

Vortex Particle Method ◽

Aerodynamic Interaction ◽

Vortex Particle

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A combined vortex and panel method for numerical simulations of viscous flows: a comparative study of a vortex particle method and a finite volume method

International Journal for Numerical Methods in Fluids ◽

10.1002/fld.1010 ◽

2005 ◽

Vol 49 (10) ◽

pp. 1087-1110 ◽

Cited By ~ 3

Author(s):

Kwang-Soo Kim ◽

Seung-Jae Lee ◽

Jung-Chun Suh

Keyword(s):

Comparative Study ◽

Numerical Simulations ◽

Finite Volume Method ◽

Finite Volume ◽

Particle Method ◽

Viscous Flows ◽

Panel Method ◽

Vortex Particle Method ◽

Volume Method ◽

Vortex Particle

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Coupling Mid-Fidelity Aerodynamics and Multibody Dynamics for the Aeroelastic Analysis of Rotary-Wing Vehicles

Energies ◽

10.3390/en14216979 ◽

2021 ◽

Vol 14 (21) ◽

pp. 6979

Author(s):

Alberto Savino ◽

Alessandro Cocco ◽

Alex Zanotti ◽

Matteo Tugnoli ◽

Pierangelo Masarati ◽

...

Keyword(s):

Multibody Dynamics ◽

Particle Method ◽

Computational Effort ◽

Preliminary Design ◽

Vortex Particle Method ◽

Aeroelastic Analysis ◽

Tiltrotor Aircraft ◽

Aircraft Configurations ◽

Rotary Wing ◽

Vortex Particle

A mid-fidelity aerodynamic solver based on the vortex particle method for wake modeling, DUST, is coupled through the partitioned multi-physics coupling library preCICE to a multibody dynamics code, MBDyn, to improve the accuracy of aeroelastic numerical analysis performed on rotary-wing vehicles. In this paper, the coupled tool is firstly validated by solving simple fixed-wing and rotary-wing problems from the open literature. The transient roll maneuver of a complete tiltrotor aircraft is then simulated, to show the capability of the coupled solver to analyze the aeroelasticity of complex rotorcraft configurations. Simulation results show the importance of the accurate representation of rotary wing aerodynamics provided by the vortex particle method for loads evaluation, aeroelastic stability assessment, and analysis of transient maneuvers of aircraft configurations characterized by complex interactional aerodynamics. The limited computational effort required by the mid-fidelity aerodynamic approach represents an effective trade-off in obtaining fast and accurate solutions that can be used for the preliminary design of novel rotary-wing vehicle configurations.

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