Computational Study of NASA's Quadrotor Urban Air Taxi Concept

Diaz, Patricia Ventura; Yoon, Seokkwan

doi:10.2514/6.2020-0302

Cited by 12 publications

(5 citation statements)

References 10 publications

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“…As for air taxis, there are much fewer publications on this topic. For example, paper [24] presents a CFD model of the flow around various parts of an air taxi and studies the mutual influence of the propellers and fuselage on the formation of a vortex flow. Paper [25] considers the complex problem of optimizing an air taxi flight with a number of parameters (speed, angle of attack) under certain constraints.…”

Section: Fig1 Air Taxi a Quadrotor Typementioning

confidence: 99%

Modeling of aerodynamic noise of quadrotor type aerotaxi

Lukianov,

Dusheba

2023

aktt

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The subject of this work is a study of the current state of modeling the flow around the blades of quadcopters, models of aerodynamic sound generation, formulation, and numerical solution of the problem of generation of rotation noise by the blades of a quadrotor type aerotaxi. The models describing the flow field around the quadrotor blades include the model of nonlinear vortices in lattices, the Reynolds-averaged Navier-Stokes equation (RANS, URANS), the large eddy simulation method (LES), and the direct numerical simulation (DNS) of the system of aerodynamic equations. This paper analyzes the main noise models of different types of aerodynamic origin. Gutin’s model is used to describe the noise of the quadrotor rotation, and the Ffowcs -Williams-Hawkings equation in the formulation of Farassat is used to model the noise taking into account various sound sources. However, these approaches have certain drawbacks that limit their application. The following paper uses a modern approach to modeling noise of aerodynamic origin based on the three-dimensional unsteady equation of sound propagation from a thin blade in the potential approximation, previously proposed by one of the authors of the work. Using this approach, a numerical calculation of the problem of sound generation (rotational noise) of the aerodynamic origin of a quadrotor type aerotaxi was performed. The purpose of the study. Despite the approaches described above, there is a problem associated with achieving an acceptable noise level, i.e. its further reduction. To solve this problem, there is a need to use more accurate models that will allow research on reducing air taxi noise. Tasks of the study. In this regard, the task of modeling noise of aerodynamic origin was set and solved using a refined model of the sound generated by the interaction of the flow and air taxi blades. Research methods are based on the construction and use of a mathematical model for the generation of rotation sound generated by the joint operation of aerotaxi rotors. On this basis, the calculations of the near and far sound fields were performed. A new model for calculating the long-range sound field of a quadrotor type aerotaxi is proposed, which considers the mutual formation of the resulting sound field from the joint operation of 4 propellers. The pressure coefficient and the sound pressure level in the distant sound field were calculated, and the frequency filling of the spectrum of the generated sound wave was investigated. Results and Conclusions. Numerical calculations of the problem of aerotaxi rotation noise generation showed that the maximum pressure level in the generated waves is in the immediate vicinity of the location of the quadrotor screws. However, the maximum value of the pressure level depends on the parameters of the problem, which vary: the thickness of the blade and the speed of the horizontal flight of the aerotaxi. As one moves away from the screws, the local maxima disappear and the wave takes the form of a flat wave. The general level of generated sound (rotational noise) is in the range of 70dB-102dB, which coincides with the results of studies of quadrotor aerotaxi, as well as taxis with the arrangement of propellers according to the aircraft type. The generated rotational noise energy is concentrated in the first 4-5 harmonics. Therefore, the noise model of aerodynamic origin proposed in this study can be used to study the rotation noise of a quadrotor type aerotaxi.

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Section: Fig1 Air Taxi a Quadrotor Typementioning

confidence: 99%

Modeling of aerodynamic noise of quadrotor type aerotaxi

Lukianov,

Dusheba

2023

aktt

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“…Diaz et al [50,51] simulated ducts' effects on coaxial rotors and analysed the aerodynamics and performance of the side-by-side air taxi. Diaz and Yoon [52] carried out a high-fidelity CFD simulation for analyzing NASA's quadrotor urban air-taxi concept. Guruswamy [53] simulated the takeoff and cruise of an air taxi using Navier-Stocks' equations.…”

Section: Technicalmentioning

confidence: 99%

Applications and classifications of unmanned aerial vehicles: A literature review with focus on multi-rotors

2022

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During the past two decades, with the advancement of avionics, control systems, design, product methods, and communication systems, UAVs have gained more interest from both civil and military customers. Hence, more researchers have dedicated their time to developing new applications for drones and improving their performance. In this study, a literature review on drone applications is conducted. It is explained that they can be more effective and beneficial when merged with preexisting systems, and thus making a system of systems. Further, we have classified UAV applications more comprehensively. This classification can be very useful for providing insights when designing new UAVs. Finally, previous works are discussed thoroughly and diagrams are developed to show the research focus in this field. These statistical diagrams can also be used as a gap analysis tool.

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“…Flow simulation with CFD has also been used to give insight into the complex and detailed flow field from multiple propellers of UAS, whether with smaller propellers (Radius < 0.5 m) in hover 24,26,31,32 and forward flight 33–36 conditions, or with larger propellers (Radius = 2–4 m) for studies on Urban Air Mobility (UAM) aircraft. 27,37–40 Such insight could be helpful in understanding, for instance, how in forward flight the thrust generation of one propeller is affected by the flow from the other propellers and thus changing the overall lift and moment on the vehicle, 33–35,38,39 or how the downwash flow field influences the spray of particles from the vehicle. 31,32,36 The crucial part, however, is the verification of the numerical calculations from the CFD simulation to make sure that the flow structure predicted is producible in an experimental setup.…”

Section: Introductionmentioning

confidence: 99%

Numerical studies on modeling the near- and far-field wake vortex of a quadrotor in forward flight

Nathanael

Wang

Low

2022

Proceedings of the Institution of Mechanical Engineers, Part G:

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The operation of Unmanned Aerial Systems (UAS) is expected to keep increasing in the future with its rapid advancement and ever-expanding applications. One of the safety measures that need to be put into place for safe UAS operations is separation requirements. This article presents the results from flow simulations of quadrotor propellers using the Overset method in ANSYS Fluent 19.2 and the Virtual Blade Model (VBM) method in OpenFOAM as part of ongoing work to establish a wake vortex–based safe separation distance for UAS operations. The near-field flow simulation using the Reynolds-averaged Navier–Stokes turbulence model was validated with mesh convergence and turbulence model studies and verified with simulation and experimental data in the literature to ensure that the propeller simulation methods could generate a realistic near-field flow of multi-rotor UAS in forward flight. The far-field flow simulation using the Large Eddy Simulation turbulence model was validated with a mesh convergence study by calculating and comparing the circulation strength of the vortices in the far-field flow of each mesh setup but not verified due to a lack of existing experimental data.

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Computational Study of NASA's Quadrotor Urban Air Taxi Concept

Cited by 12 publications

References 10 publications

Modeling of aerodynamic noise of quadrotor type aerotaxi

Modeling of aerodynamic noise of quadrotor type aerotaxi

Applications and classifications of unmanned aerial vehicles: A literature review with focus on multi-rotors

Numerical studies on modeling the near- and far-field wake vortex of a quadrotor in forward flight

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