Aerodynamic Analysis of the Ducted Fan for a VTOL UAV in Crosswinds

Abstract

An aerodynamic analysis of a ducted fan for vertical take-off and landing unmanned aerial vehicles was performed using computational simulation. A commercial computational fluid dynamics tool was used to solve the Reynolds-averaged Navier-Stokes equations. The calculated results were validated in the subsonic wind tunnel at Hanyang University. The objective of this study is to investigate the aerodynamic performance of a ducted fan in crosswinds. The thrust, normal and side forces of the ducted fan are affected by the velocity magnitude and in-flow angle of the crosswind. The pitching moment of the ducted fan is significantly influenced by the crosswind due to asymmetric lift force created by the difference in suction velocity magnitude on the duct lip. Flow separation at the duct lip occurs under hovering and crosswind conditions. The inlet flow fields of the ducted fan are distorted by the duct lip separation. In conclusion, to improve the stability of the ducted fan, the pitching moment must be reduced.

High Performance Convertible Coleopter Drones

“…Many short-coupled ducted fan designs such as the one described above have been studied with special attention paid to pitchback instability because it is the primary "show-stopper" for this class of aircraft [9]. Other works examine static aerodynamics of short-coupled coleopter designs independent of fully free-body aeromechanical modes [10,11]. This is understandable as the demonstrated dangers of conversion testing (described above) often lead to complete hull loss given the problems with pitchback instabilities.…”

“…Drones 2022, 6, x FOR PEER REVIEW 6 of 29 [9]. Other works examine static aerodynamics of short-coupled coleopter designs independent of fully free-body aeromechanical modes [10,11]. This is understandable as the demonstrated dangers of conversion testing (described above) often lead to complete hull loss given the problems with pitchback instabilities.…”

“…The principal loads experiences by the aircraft come not from in-flight airloads, but handling, landing, crash, and wall-impact. The ply layers and thicknesses on the central fuselage on the XQ-138 (11), for example, were set by hand-crush loads during engine start. The landing gear-to-rotor guard junctures were designed to accommodate run-on high descent landings.…”

A Study on Hover Performance of Ducted Fans for an Unmanned VTOL Aircraft

“…Research on the ducted fan has been actively implemented from the early 2000s until recently, and the studies were mainly focused on a single ducted fan for a small UAV (unmanned aerial vehicle) that requires VTOL (vertical take-off and landing) ability in the 2000s [1][2][3]. After the 2010s, as VTOL vehicles of various concepts including small UAVs were introduced, various forms of ducted fans appeared naturally such as fan-in-wing [4][5][6], multiduct [7], and coaxial [8,9] types. In addition, studies have been conducted on the performance of ducted fans in various ways.…”

Optimization of sampling structure on UAV for gas leakage monitoring in the atmosphere

“…Xue [40] and Li et al [41] simulated the fuselage turbulence of hovering twin rotor UAV. Ryu et al [42] analyzed the turbulence effect of UAV in crosswind environment, and Seong [43] analyzed the fuselage flow field distribution of four rotor UAV in forward flight attitude. The downwash flow field generated by multirotor UAV is more complex than that by a single rotor, and the flow field of multi-rotors will induce and affect with each other, resulting in aggregation flow.…”