Aerodynamic Interactions of Quadrotor Configurations

Barcelos, Devin F.; Kolaei, Amir; Bramesfeld, Goetz

doi:10.2514/1.c035614

Cited by 28 publications

(6 citation statements)

References 19 publications

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“…The second is known as a diamond configuration, with a single leading and trailing rotor and two outboard rotors. A detailed aerodynamic analysis of these two configurations is given by Barcelos et al (54), which indicates highly complex aerodynamic effects primarily due to the proximity of the rotors.…”

Section: Discussionmentioning

confidence: 99%

A Distributed Doublet-Based Method for Unsteady Aerodynamic Analysis with Relaxed Wakes

Krebs

2023

Preprint

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A novel potential flow-based method for unsteady aerodynamic analysis with relaxed wakes is presented. This method models aerodynamic surfaces and wakes using distributed doublet elements (DDEs) of parabolic strength in both the spanwise and streamwise directions. Due to the nature of the method, the velocities induced by a DDE-based system are bounded everywhere, meaning there are no non-physical or infinite induced velocities in the velocity field, as opposed to lower-order filament-based potential flow methods. In addition to providing a robust velocity field, the use of DDEs provides a degree of stability in predicting unsteady forces that is unachievable with conventional lower-order methods. The DDE-based method was validated through a series of four studies. The first study predicted the span efficiency of various planar elliptical wings, which agreed with the classical lifting line solution to within 3%. The second study predicted the unsteady lift response to an airfoil passing through a sharp-edged gust, which matched the analytical solution provided by the Küssner function, illustrating the stability of the unsteady force calculations within the DDE-based method. The third study predicted the unsteady time-averaged thrust force produced by a small, rigid rotor at various tip-path plane angles and advance ratios, matching experimentally-obtained data to within 10%. The final study compared the transient sectional thrust of a small, rigid rotor blade operating under unsteady conditions to those obtained via a CFD-based analysis. The comparison agreed well in magnitude and azimuthal location. Two exploratory studies focusing on small, rigid rotors were performed to demonstrate potential applications of the DDE-based method. The first study quantified the impacts of rolling maneuvers on the time-averaged thrust and moments of a rigid rotor, with the results indicating that a rolling maneuver can have a significant effect on the thrust and roll moment coefficients. The second study predicted the transient thrust of two rotors operating under multiple tip-path plane angles and advance ratios, showing transient thrust oscillations of up to 60% of the mean thrust output in some cases. The thrust output of individual rotor blades oscillated by up to 90% of the mean total rotor thrust under certain conditions.

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Section: Discussionmentioning

confidence: 99%

A Distributed Doublet-Based Method for Unsteady Aerodynamic Analysis with Relaxed Wakes

Krebs

2023

Preprint

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“…S6), due to the different Reynolds number and propeller geometry that are not accounted for by momentum theory (39). Then, installing the four propellers on the quadrotor airframe would further introduce rotor-to-rotor interactions (41)(42)(43) and rotor-to-body interactions (44), which would cause a further efficiency drop (for the 7.5inch propeller quadrotor, the drop is about 5.99%). In contrast, PULSAR eliminates this rotor-to-rotor interaction and mitigates the rotor-to-body interaction by placing the UAV body under the propeller hub, leading to an efficiency drop of merely 2.88%.…”

Section: Energy Efficiencymentioning

confidence: 99%

A self-rotating, single-actuated UAV with extended sensor field of view for autonomous navigation

et al. 2023

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Uncrewed aerial vehicles (UAVs) rely heavily on visual sensors to perceive obstacles and explore environments. Current UAVs are limited in both perception capability and task efficiency because of a small sensor field of view (FoV). One solution could be to leverage self-rotation in UAVs to extend the sensor FoV without consuming extra power. This natural mechanism, induced by the counter-torque of the UAV motor, has rarely been exploited by existing autonomous UAVs because of the difficulties in design and control due to highly coupled and nonlinear dynamics and the challenges in navigation brought by the high-rate self-rotation. Here, we present powered-flying ultra-underactuated LiDAR (light detection and ranging) sensing aerial robot (PULSAR), an agile and self-rotating UAV whose three-dimensional position is fully controlled by actuating only one motor to obtain the required thrust and moment. The use of a single actuator effectively reduces the energy loss in powered flights. Consequently, PULSAR consumes 26.7% less power than the benchmarked quadrotor with the same total propeller disk area and avionic payloads while retaining a good level of agility. Augmented by an onboard LiDAR sensor, PULSAR can perform autonomous navigation in unknown environments and detect both static and dynamic obstacles in panoramic views without any external instruments. We report the experiments of PULSAR in environment exploration and multidirectional dynamic obstacle avoidance with the extended FoV via self-rotation, which could lead to increased perception capability, task efficiency, and flight safety.

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“…The propagation of vortices plays a crucial role in aerodynamic interactions between front and aft rotors and differs depending on the parameters like advance ratio or rotor disk loading (Refs. [2][3][4]. An important design variable strongly affecting the interactional effects is the rotor spacing, which was proved for bi-rotor configurations experimentally (Refs.…”

Section: Introductionmentioning

confidence: 98%

Experimental Investigation of Quadrotor Aerodynamics with Computational Cross-Validation

Kostek¹,

Riziotis²,

Miesner³

et al. 2023

Proceedings of the Vertical Flight Society 79th Annual Forum

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The influence of interactional effects on quadrotor performance in forward flight was evaluated taking into account square and diamond configurations, forward and backward tilt angles and a range of hub spacings including overlapping blades. The analysis was based on the wind-tunnel measurements and simulations from five computational methods with different fidelity levels. The outcome indicates that the efficiency of a diamond configuration improves in comparison with isolated rotors for non-overlapping rotor spacings, while the interactions in square alignments are detrimental for all analysed test cases. The computational results showed good agreement with the measurement data for the forward rotor plane tilt, however for the increased rotor-wake interactions at a backward tilt angle the spread between the calculated values, especially for torque, could be observed with the general trends maintained. The study proves the diamond configuration with 1.2 D rotor spacing and tip-to-tip rotor phasing to be most favourable in analysed conditions in terms of both aerodynamic performance and acoustic signature.

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Aerodynamic Interactions of Quadrotor Configurations

Cited by 28 publications

References 19 publications

A Distributed Doublet-Based Method for Unsteady Aerodynamic Analysis with Relaxed Wakes

A Distributed Doublet-Based Method for Unsteady Aerodynamic Analysis with Relaxed Wakes

A self-rotating, single-actuated UAV with extended sensor field of view for autonomous navigation

Experimental Investigation of Quadrotor Aerodynamics with Computational Cross-Validation

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