Citation: Ahmed Snikdha, S.S.; Chen,
S.-H. A Computational Investigation
of the Hover Mechanism of an
Innovated Disc-Shaped VTOL UAV.
Drones 2023, 7, 105. https://doi.org/
10.3390/drones7020105
Academic Editors: Andrzej
Łukaszewicz, Wojciech Giernacki,
Zbigniew Kulesza, Jaroslaw Pytka
and Andriy Holovatyy
Received: 22 December 2022
Revised: 24 January 2023
Accepted: 31 January 2023
Published: 3 February 2023
Copyright: © 2023 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
Article
A Computational Investigation of the Hover Mechanism of an
Innovated Disc-Shaped VTOL UAV
Samia Shahrin Ahmed Snikdha * and Shih-Hsiung Chen
Department of Aeronautics and Astronautics (DAA), College of Engineering, National Cheng Kung University,
No. 1, University Rd, East District, Tainan City 701, Taiwan
* Correspondence: p48087065@gs.ncku.edu.tw
Abstract:
Inventive approaches are constantly being revealed in the field of vertical take-off and
landing (VTOL) unmanned aerial vehicle (UAV) configuration concepts and designs. To date, a
body-associated configuration of UAVs for augmented lift remains unclear among other approached
designs. The current paper investigates the mechanism of a high-lift ducted fan mounted in the
central body for VTOL UAV designs. We report an unresolved design of a disc-shaped UAV with
a single rotor that aims to enhance the cost-effectiveness of fuel consumption with a substantial
contribution of body lift to hover thrust. The convex upper surface curvature was applied to generate
a significant lift contribution from the body during hover. The computational fluid dynamics (CFD)
approach based on unstructured discretization followed by three-dimensional steady Reynolds-
averaged Navier–Stokes (RANS) flow was applied in ANSYS CFX to mechanistically investigate the
underlying design considerations. The disc-shaped UAV uses the lip curvature on the duct inlet to
generate a vertical force that demonstrates a significant contribution of 95% of the rotor thrust during
hovering. The UAV’s upper surface generates prolonged flow entrainment free from momentum
losses in swirling flows. This phenomenon is followed by reduced power consumption in hovering
and vertical flight, making the UAV aerodynamically stable and environmentally safe.
Keywords:
computational fluid dynamics (CFD); VTOL UAV; disc-shaped drone; hover; vertical flight
1. Introduction
From the beginning of the 21st century, researchers and industries have been com-
ing forward to model the innovative engineering designs of effective flying drones with
improved aerodynamic performances and capabilities. A recent review report [
1
], gave
an overview of the types of UAVs and their subsystems and evaluated different appli-
cations related to remote sensing, spraying of liquids, and logistics. Another study [
2
],
reported a classification, a broad spectrum of applications, and the existing challenges of
UAV designs. Some of the most common applications of flying drones are remote sensing;
aerial photography for completing intelligence, surveillance, and reconnaissance missions;
environmental protection; mailing and delivery; and other miscellaneous applications.
The rotary wing design of UAVs or drones allows them to fly at high speeds and
perform VTOL and hovering flight; however, to date, challenges associated with efficient
performance in cruise flight are being faced [
3
]. Although rotary-wing drones have simple
control systems and they are maneuverable, their main disadvantage is power consump-
tion [
4
,
5
]. The aerodynamic interactions between multiple rotors, fuselage, and lifting
bodies add further complexities. The SUI endurance simulations of forward flight in [
6
]
have provided insight into better designs during cruise; under-mounting the fore rotors
and over-mounting the aft rotors improves the aerodynamic efficiency of the vehicle. The
hybrid SUI increases the forward horizontal force by 63% compared to the standard SUI.
However, even with mild rotor–rotor interactions, the aerodynamic performance of the
vehicle is affected, thus requiring design improvements. The authors of [
6
] conducted a
Drones 2023, 7, 105. https://doi.org/10.3390/drones7020105 https://www.mdpi.com/journal/drones
