scholarly journals Effects of Wind Disturbance on the Aerodynamic Performance of a Quadrotor MAV during Hovering

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yao Lei ◽  
Yiyong Huang ◽  
Hengda Wang
Keyword(s):  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Vertical Wind ◽  
Horizontal Wind ◽  
Wind Disturbance ◽  
Power Variation ◽  
Quadrotor Aircraft ◽  
Spacing Ratio ◽  
Power Loading ◽  
Vertical Winds

Wind disturbance could render thrust and power variation or even causing roll which is difficult to maintain a steady flight in gust especially when the horizontal or vertical wind is involved. In this paper, the horizontal wind and vertical wind are presented to study the influence of wind disturbance on aerodynamic characteristics of the quadrotor aircraft in hovering by experiments and numerical simulations. First, the simplified aerodynamic model with the wind disturbance was analyzed in detail. Also, the low-speed wind tunnel tests were performed to obtain the thrust and power variation of the quadrotor aircraft with rotor spacing ratio s = 1.1 -1.8 in both horizontal and vertical winds of 0-5 m/s with the rotational speed ranging from 1500 to 2300 rpm. Finally, the simulations are performed by utilizing the Computational Fluid Dynamics (CFD) software ANSYS to study the flow field distribution of quadrotor with the influence of the wind disturbance. The comparison between experimental results and simulation results shows that the quadrotor achieves better aerodynamic performance with larger thrust and smaller power consumption at rotor spacing ratio s = 1.8 . Additionally, the quadrotor can effectively resist the horizontal wind disturbance, which will bring larger power loading for the quadrotor, especially at 2.5 m/s. However, the vortices near blade-tip move upwards and deform with the influence of vertical wind, resulting in the reduction of thrust and aerodynamic performance of the quadrotor.

scholarly journals Horizontal Wind Effect on the Aerodynamic Performance of Coaxial Tri-Rotor MAV

2020 ◽  
Vol 10 (23) ◽  
pp. 8612
Author(s):  
Yao Lei ◽  
Yiqiang Ye ◽  
Zhiyong Chen
Keyword(s):  
Wind Tunnel ◽  
Power Consumption ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Horizontal Wind ◽  
Wind Effect ◽  
Rotor Speed ◽  
Wind Tunnel Experiments ◽  
Air Vehicle ◽  
Power Loading

The coaxial Tri-rotor micro air vehicle (MAV) is composed of three coaxial rotors where the aerodynamic characteristics of is complicated in flight especially when the wind effect is introduced. In this paper, the hovering performance of a full-scale coaxial Tri-rotor MAV is analyzed with both the simulations and wind tunnel experiments. Firstly, the wind effect on the aerodynamic performance of coaxial Tri-rotor MAV is established with different rotor speed (1500–2300 rpm) and horizontal wind (0–4 m/s). Secondly, the thrust and power consumption of coaxial Tri-rotor (L/D = 1.6) were obtained with low-speed wind tunnel experiments. Furthermore, the streamline distribution, pressure distribution, velocity contour and vortex distribution with different horizontal wind conditions are obtained by numerical simulations. Finally, combining the experiment results and simulation results, it is noted that the horizontal wind may accelerate the aerodynamic coupling, which resulting in the greater thrust variation up to 9% of the coaxial Tri-rotor MAV at a lower rotor speed. Moreover, the aerodynamic performance is decreased with more power consumption at higher rotor speed where the wind and the downwash flow are interacted with each other. Compared with no wind flow, the shape of the downwash flow and the deformation of the vortex affect the power loading and figure of metric accordingly.

scholarly journals Aerodynamic Characteristics of a Micro Multi-Rotor Aircraft with 12 Rotors Considering the Horizontal Wind Disturbance

2020 ◽  
Vol 10 (20) ◽  
pp. 7387
Author(s):  
Yao Lei ◽  
Wenjie Yang ◽  
Hengda Wang
Keyword(s):  
Power Consumption ◽  
Micro Air Vehicles ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Horizontal Wind ◽  
Wind Disturbance ◽  
Wind Speeds ◽  
Hover Performance ◽  
Blade Tip ◽  
Cfd Method

Wind disturbance posed difficulties for the stability of the micro air vehicles (MAVs) with attitude variation. In this paper, the aerodynamic performance of a MAV with six coaxial rotor pairs considering the horizontal wind is investigated by both experiments and numerical simulations. First, the effect of the horizontal wind on the multi-rotor aircraft is analyzed in detail. Then, low-speed wind tunnel tests were performed to obtain the thrust and power consumption and the aerodynamic performance of the multi-rotor aircraft (l/D = 1.2 and h/D = 0.19) with the rotational speed of 1500–2300 r/min in the horizontal wind ranged from 0 to 5 m/s. Finally, the distribution of streamline, the pressure of the blade tip, and the velocity and the vortices in the flow field of a multi-rotor aircraft with horizontal wind disturbance, were simulated and studied using the computational fluid dynamics (CFD) method. Through the comparison of experimental results and simulation results, it can be seen that the horizontal wind disturbance will increase power consumption to weaken the aerodynamic performance at higher rotor speeds. However, larger thrust and better hover performance are obtained at lower rotational speeds with good wind resistance. Additionally, due to the mutual induction between rotor wakes, the interactions of downwash flows become more intense at higher rotational speeds or larger wind speeds where the vortexes at the blade tip deformed and moved along with the wind.

scholarly journals The aerodynamic performance of Non-planar hex-rotors aircraft subjected the horizontal wind disturbanceLei yao1,2* Ma Chensong1 Feng Zhicheng1

2021 ◽  
Author(s):  
Lei yao ◽  
Ma Chensong ◽  
Feng Zhicheng
Keyword(s):  
Wind Speed ◽  
Power Consumption ◽  
Tilt Angle ◽  
Wind Tunnel Test ◽  
Aerodynamic Performance ◽  
Horizontal Wind ◽  
Horizontal Wind Speed ◽  
Power Loading ◽  
Experimental Values ◽  
Cfd Method

Abstract The non-planar hex-rotor aircraft mentioned in this article can change its flight status by simply changing the tilt angle of the rotor. In this paper, mainly studied the best aerodynamic performance of a non-planar hex-rotor aircraft under the influence of horizontal wind (0m/s, 2.5m/s and 4m/s). Firstly, the rotation speed of the rotor is a fixed value (2200r/min) in the low-speed wind tunnel test, the horizontal wind speed and the tilt angle of the rotor are variable values, the thrust, power consumption and power loading(PL) values of the aircraft are obtained. Secondly, the computational fluid dynamics(CFD) method is used to simulate the aerodynamic performance of a non-planar hex-rotors aircraft when subjected to a horizontal wind to obtain the simulation results. Finally, comparing the experimental values and the simulation values, it is found that the horizontal speed has a greater impact on the thrust and power consumption of the non-planar hex-rotor aircraft. From the change of PL values, it is concluded that the horizontal wind speed is 0m/s, 2.5m/s, 4m/s, the best inclination angle is 10°, 30°and 50°, and the strongest anti-wind performance.

scholarly journals Aerodynamic Optimization of a Micro Quadrotor Aircraft with Different Rotor Spacings in Hover

2020 ◽  
Vol 10 (4) ◽  
pp. 1272 ◽  
Author(s):  
Yao Lei ◽  
Hengda Wang
Keyword(s):  
Numerical Simulations ◽  
Negative Impact ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Aerodynamic Optimization ◽  
Quadrotor Aircraft ◽  
Blade Tip ◽  
Computational Fluid Dynamics Cfd ◽  
Aerodynamic Interference ◽  
Cfd Method

In order to study the aerodynamic performance of the quadrotor with different rotor spacings in hover, experiments were performed together with numerical simulations. For experimental study, an experimental platform was designed to measure the thrust and power consumption of the quadrotor with different rotor spacings (L/R = 2.2, 2.6, 3.0, 3.2, 3.6, and 4.0), and to attempt to find out the optimal rotor configuration which makes the quadrotor have the best aerodynamic performance. In addition, the pressure distribution, vorticity of the blade tip, and velocity vector of quadrotor in the flow field were obtained by Computational Fluid Dynamics (CFD) method to visually analyze the aerodynamic interference between adjacent rotors. By the comparison of experimental results and numerical simulations, the final results show that the aerodynamic performance of the quadrotor varies obviously with the change of rotor spacing, and it has a negative impact on hover efficiency if rotor spacing is too much small or large. The rotors pacing at L/R = 3.6 with larger thrust and smaller power is considered to be the best aerodynamic configuration for the quadrotor with better aerodynamic characteristics. Furthermore, compared with the isolated rotor, moderate aerodynamic interference is proved to help improve the aerodynamic performance of the quadrotor with a larger thrust, especially for a rotor spacing at L/R = 3.6.

scholarly journals Characteristics and performance of vertical winds as observed by the radar wind profiler network of China

2020 ◽  
Author(s):  
Boming Liu ◽  
Jianping Guo ◽  
Wei Gong ◽  
Lijuan Shi ◽  
Yong Zhang ◽  
...  
Keyword(s):  
Wind Speed ◽  
Numerical Weather Prediction ◽  
Weather Prediction ◽  
Vertical Wind ◽  
Horizontal Wind ◽  
Wind Profiler ◽  
Numerical Weather ◽  
And Performance ◽  
Wind Profiles ◽  
Vertical Winds

Abstract. Vertical wind profiles are the foundation for numerical weather prediction systems research. Large-scale vertical wind data have been previously documented from network observations in several countries, but the nationwide vertical wind observations are poorly understood in China. In this study, the salient characteristics and performance of vertical winds as observed by the radar wind profiler network of China was investigated, which consists of more than 100 stations instrumented with 1290-MHz Doppler radar designed primarily for measuring vertical-resolved winds. This network has good spatial coverage, with denser sites in coastal areas. The vertical wind profiles observed by this network can provide the horizontal wind direction, horizontal wind speed, and vertical wind speed for every 120 m interval within the height of 0 to 3 km. The availability of the radar wind profiler network has been investigated in terms of effective detection height, data acquisition rate, data confidence, and data accuracy. Further comparison analysis with reanalysis data indicated that the observation data at 89 stations are recommended, and 17 stations are unrecommended. The vertical wind profiles can serve as important input dataset assimilated into numerical weather prediction system at both regional and global scales.

scholarly journals Aerodynamic performance of a Hex-rotor unmanned aerial vehicle with different rotor spacing

2020 ◽  
Vol 53 (3-4) ◽  
pp. 711-718
Author(s):  
Yao Lei ◽  
Mingxin Cheng
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Necessary Conditions ◽  
Experimental Tests ◽  
Aerodynamic Performance ◽  
Spacing Ratio ◽  
Test Platform ◽  
Power Loading ◽  
Aerial Vehicle ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

In this paper, an attempt was made to obtain the aerodynamic performance of a Hex-rotor unmanned aerial vehicle with different rotor spacing. The hover efficiency of the Hex-rotor unmanned aerial vehicle is analyzed by both experimental tests and numerical simulations. First, a series of index to characterize the aerodynamic performance of the Hex-rotor unmanned aerial vehicle are analyzed theoretically, and then both tests and simulations on a Hex-rotor unmanned aerial vehicle with different rotor spacing ratio ( i = 0.50, 0.56, 0.63, 0.71, 0.83) were presented in details. For a custom-designed test platform, the thrust, power loading and hover efficiency of the Hex-rotor unmanned aerial vehicle were obtained in this paper. Finally, computational fluid dynamics simulations are performed to obtain the streamline distributions of the flow field, pressure and velocity contour of the Hex-rotor unmanned aerial vehicle. Results show that the aerodynamic performance of the Hex-rotor unmanned aerial vehicle is varied by changing the rotor spacing. Specifically, the smaller rotor spacing may improve the aerodynamic performance of the Hex-rotor unmanned aerial vehicle by increasing the rotor interferences. In the meantime, the effects of mutual interference between the rotors are gradually reduced with the increase of the rotor spacing. Moreover, the uniformity of the streamline distribution, the shape and the symmetry of the vortex are necessary conditions for the Hex-rotor unmanned aerial vehicle to generate a larger thrust. It was also noted that the thrust increased by 5.61% and the overall efficiency increased by about 8.37% at i = 0.63 for the working mode (2200 r/min), which indicated that the rotor spacing ratio at i = 0.63 obtained a best aerodynamic performance.

scholarly journals Effect of wind disturbance on the aerodynamic performance of coaxial rotors during hovering

2019 ◽  
Vol 52 (5-6) ◽  
pp. 665-674 ◽  
Author(s):  
Yao Lei ◽  
Rongzhao Lin
Keyword(s):  
Wind Tunnel ◽  
Flow Field ◽  
Micro Air Vehicles ◽  
Aerodynamic Performance ◽  
Vertical Wind ◽  
Wind Gust ◽  
Wind Disturbance ◽  
Wind Tunnel Tests ◽  
Coaxial Rotors ◽  
Air Vehicles

The ability to resist the effect of wind disturbance is vital for micro air vehicles. As the most compact rotor configuration for micro air vehicles, coaxial rotors will be the preferred choice for this type of devices. In this paper, the aerodynamic performance of the coaxial rotors considering the wind gust is presented with both experiments and simulations. First, effect of wind disturbances on the micro air vehicles flight was introduced. Then, low-speed wind tunnel tests were performed on a coaxial rotor with a spacing 0.39 R to obtain the performance in both horizontal and vertical wind of 0–5 m/s with the revolutions per minute ranging from 1500 to 2400. Finally, computational fluid dynamics simulations, as a means of visualizing the flow field to compensate the intuition of the experimental data, were applied by using the sliding mesh to capture the detailed interference of flow field with the distributions of streamline and velocity vector. Compared with wind tunnel tests, simulation results were highly consistent with experiments that allow to capture the flow details around the rotor tip effectively. In addition, the aerodynamic performance was deteriorated by vortices moving or deforming around the blade tip. Also, coaxial rotors can effectively resist the wind disturbance in the horizontal direction while the rotor performance was found to be declined in the vertical wind.

scholarly journals Mean vertical wind in the mesosphere-lower thermosphere region (80–120 km) deduced from the WINDII observations on board UARS

1997 ◽  
Vol 15 (9) ◽  
pp. 1221-1231 ◽  
Author(s):  
V. Fauliot ◽  
G. Thuillier ◽  
F. Vial
Keyword(s):  
Continuity Equation ◽  
Emission Rate ◽  
Lower Thermosphere ◽  
Line Emission ◽  
Vertical Wind ◽  
Horizontal Wind ◽  
Heating And Cooling ◽  
The Mean ◽  
Mesosphere And Lower Thermosphere ◽  
Vertical Winds

Abstract. The WINDII interferometer placed on board the Upper Atmosphere Research Satellite measures temperature and wind from the O(1S) green-line emission in the Earth's mesosphere and lower thermosphere. It is a remote-sensing instrument providing the horizontal wind components. In this study, the vertical winds are derived using the continuity equation. Mean wind annually averaged at equinoxes and solstices is shown. Ascendance and subsidence to the order of 1–2 cm s–1 present a seasonal occurrence at the equator and tropics. Zonal Coriolis acceleration and adiabatic heating and cooling rate associated to the mean meridional and vertical circulations are evaluated. The line emission rate measured together with the horizontal wind shows structures in altitude and latitude correlated with the meridional and vertical wind patterns. The effect of wind advection is discussed.

scholarly journals Investigation on aerodynamic characteristics of bionic membrane nano rotor

2021 ◽  
Vol 18 ◽  
pp. 175682932110433
Author(s):  
Shanyong Zhao ◽  
Zhen Liu ◽  
Ke Lu ◽  
Dacheng Su ◽  
Shangjing Wu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Structural Parameters ◽  
Element Model ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Dynamics Model ◽  
Interaction Method ◽  
Calculation Results ◽  
The Finite Element Model

In this paper, the bionic membrane structure is introduced to improve the aerodynamic performance of nano rotor at the low Reynolds number. The aerodynamic characteristics of nano rotor made of hyperelastic material as membrane blades are studied. Firstly, based on the hyperelastic constitutive model, a finite element model of the rotor is established and compared with the results of the modal test to verify the accuracy of the model. Then the computational fluid dynamics model of membrane nano rotor is established which combined with the finite element model. The aerodynamic characteristics of the membrane rotor under hovering conditions are studied using fluid–structure interaction method. It is found that the calculation results matched well with the experiment results. The design of the structural parameters such as the membrane proportion, shape, and position of the membrane rotor is optimized. The influence of each parameter on the aerodynamic performance of the rotor is obtained. Under certain structural conditions, the performance can be effectively improved, which provides a new idea for the design of the nano rotor.

scholarly journals Adaptive Beamforming Technique for Accurate Vertical Wind Measurements with Multichannel MST Radar

2012 ◽  
Vol 29 (12) ◽  
pp. 1769-1775 ◽  
Author(s):  
Koji Nishimura ◽  
Takuji Nakamura ◽  
Toru Sato ◽  
Kaoru Sato
Keyword(s):  
Signal To Noise Ratio ◽  
Adaptive Beamforming ◽  
Vertical Wind ◽  
Constrained Minimization ◽  
Horizontal Wind ◽  
Signal To Noise ◽  
Mst Radar ◽  
Vertical Beam ◽  
Noise Ratio ◽  
Beamforming Technique

Abstract Aspect-sensitive backscattering of the atmosphere causes a small error in an effective line-of-sight direction in vertical beam observations leading to a serious degradation of vertical wind estimates due to contamination by horizontal wind components. An adaptive beamforming technique for a multichannel mesosphere–stratosphere–troposphere (MST) radar is presented, which makes it possible to measure the vertical wind velocity with higher accuracy by adaptively generating a countersteered reception beam against an off-vertically shifted echo pattern. The technique employs the norm-constrained direction-constrained minimization of power (NC-DCMP) algorithm, which provides not only robustness but also higher accuracy than the basic direction-constrained minimization of power algorithm in realistic conditions. Although the technique decreases the signal-to-noise ratio, the ratio is controlled and bound at a specified level by the norm constraint. In the case that a decrease of −3 dB is acceptable in a vertical beam observation, for which usually a much higher signal-to-noise ratio is obtained than for oblique beams, the maximum contamination is suppressed to even for the most imbalanced aspect sensitivity.

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