Propeller locations study of a generic delta wing UAV model

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Khushairi Amri Kasim ◽  
Shabudin Mat ◽  
Iskandar Shah Ishak ◽  
Shuhaimi Mansor
Keyword(s):  
Surface Pressure ◽  
Vortex Breakdown ◽  
Delta Wing ◽  
Measurement Techniques ◽  
Flow Characteristics ◽  
Aerodynamic Characteristics ◽  
Primary Vortex ◽  
Content Type ◽  
Aerodynamic Properties ◽  
Advance Ratio

Purpose This study aims to investigate the effects of propeller locations on the aerodynamic characteristics of a generic 55° swept angle sharp-edged delta wing unmanned aerial vehicle (UAV) model. Design/methodology/approach A generic delta-winged UAV model has been designed and fabricated to investigate the aerodynamic properties of the model when the propeller is placed at three different locations. In this research, the propeller has been placed at three different positions on the wing, namely, front, middle and rear. The experiments were conducted in a closed-circuit low-speed wind tunnel at speeds of 20 and 25 m/s corresponding to 0.6 × 106 and 0.8 × 106 Reynolds numbers, respectively. The propeller speed was set at constant 6,000 RPM and the angles of attack were varied from 0° to 20° for all cases. During the experiment, two measurement techniques were used on the wing, which were the steady balance measurement and surface pressure measurement. Findings The results show that the locations of the propeller have significant influence on the lift, drag and pitching moment of the UAV. Another important observation obtained from this study is that the location of the propeller can affect the development of the vortex and vortex breakdown. The results also show that the propeller advance ratio can also influence the characteristics of the primary vortex developed on the wing. Another main observation was that the size of the primary vortex decreases if the propeller advance ratio is increased. Practical implications There are various forms of UAVs, one of them is in the delta-shaped planform. The data obtained from this experiment can be used to understand the aerodynamic properties and best propeller locations for the similar UAV aircrafts. Originality/value To the best of the author’s knowledge, the surface pressure data available for a non-slender delta-shaped UAV model is limited. The data presented in this paper would provide a better insight into the flow characteristics of generic delta winged UAV at three different propeller locations.

Aerodynamic characteristics of delta wing–body combinations at high angles of attack

1994 ◽  
Vol 98 (975) ◽  
pp. 159-170 ◽  
Author(s):  
P. R. Viswanath ◽  
S. R. Patil
Keyword(s):  
Vortex Breakdown ◽  
Delta Wing ◽  
Aerodynamic Characteristics ◽  
Surface Flow ◽  
Flow Visualisation ◽  
Symmetric Flow ◽  
Gradual Process ◽  
Wing Sweep ◽  
The Mean ◽  
High Angles Of Attack

AbstractAn experimental study investigating the aerodynamic characteristics of generic delta wing-body combinations up to high angles of attack was carried out at a subsonic Mach number. Three delta wings having sharp leading edges and sweep angles of 50°, 60° and 70° were tested with two forebody configurations providing a variation of the nose fineness ratio. Measurements made included six-component forces and moments, limited static pressures on the wing lee-side and surface flow visualisation studies. The results showed symmetric flow features up to an incidence of about 25°, beyond which significant asymmetry was evident due to wing vortex breakdown, forebody vortex asymmetry or both. At higher incidence, varying degrees of forebody-wing vortex interaction effects were seen in the mean loads, which depended on the wing sweep and the nose fineness ratio. The vortex breakdown on these wings was found to be a gradual process, as implied by the wing pressures and the mean aerodynamic loads. Effects of forebody vortex asymmetry on the wing-body aerodynamics have also been assessed. Comparison of Datcom estimates with experimental data of longitudinal aerodynamic characteristics on all three wing-body combinations indicated good agreement in the symmetric flow regime.

Tuft Flow Visualisation on UTM-LST VFE-2 Delta Wing Model Configuration at High Angle of Attacks

2020 ◽  
Vol 17 (3) ◽  
pp. 8214-8223
Author(s):  
M. Said ◽  
M. Imai ◽  
S. Mat ◽  
M. N. Dahalan ◽  
S. Mansor ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Surface Pressure ◽  
Delta Wing ◽  
Measurement Techniques ◽  
Initial Point ◽  
Leading Edge ◽  
Flow Visualisation ◽  
Pressure Measurements ◽  
Wing Model ◽  
High Angles Of Attack

This paper reports on flow visualisation and surface pressure measurements over the upper surface of a blunt-edged delta wing model at high angles of attack. The flow structure above the upper surface of the blunt-edged delta wing was found to be different compared to delta wing with sharp leading edge. The flow becomes more complicated especially in the leading edge region of the wing. Currently, there is no data available to verify if the primary vortex could reach the apex of the wing when the angle of attack is further increased. Most prior experiments were performed at the angles of attack, α, below 23° with only a few experiments that had gone to α = 27°. These prior experiments and some CFD works stipulated that the attached flow continue to exist in the apex region of the delta wing even at very high angles of attack above 23°. In order to verify this hypothesis, several experiments at high angles of attack were conducted in Universiti Teknologi Malaysia Low Speed wind Tunnel (UTM–LST), using a specially constructed VFE2 wing model equipped with blunt leading edges. This series of experiments employed two measurement techniques; the first was the long tuft flow visualisation method, followed by surface pressure measurements. The experiments were performed at Reynolds numbers of 1.0×106 and 1.5×106.  During these experiments, several interesting flow characteristics were observed at high angles of attack, mainly that the flow became more sensitive to changes in Reynolds number and the angles of attack of the wing. When the Reynolds number increased from 1×106 to 1.5×106, the upstream progression of the initial point of the main vortex was relatively delayed compared to the sharp-edged delta wing. The experiments also showed that the flow continued to be attached in the apex region up to α = 27º.

Diamond, cropped, delta, and double-delta wing vortex breakdown during dynamic pitching

AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 567-569
Author(s):  
Roy Y. Myose ◽  
Boon-Kiat Lee ◽  
Shigeo Hayashibara ◽  
L. S. Miller
Keyword(s):  
Vortex Breakdown ◽  
Delta Wing ◽  
Double Delta Wing

Effects of a vectored trailing edge jet on delta wing vortex breakdown

2003 ◽  
Vol 34 (5) ◽  
pp. 651-654 ◽  
Author(s):  
J. J. Wang ◽  
Q. S. Li ◽  
J. Y. Liu
Keyword(s):  
Vortex Breakdown ◽  
Delta Wing ◽  
Trailing Edge

scholarly journals Numerical investigation of unsteady vortex breakdown past 80°/65° double-delta wing

2014 ◽  
Vol 27 (3) ◽  
pp. 521-530 ◽  
Author(s):  
Jian Liu ◽  
Haisheng Sun ◽  
Zhitao Liu ◽  
Zhixiang Xiao
Keyword(s):  
Numerical Investigation ◽  
Vortex Breakdown ◽  
Delta Wing ◽  
Double Delta Wing

Effects of air mattress pressure on sleep quality and physiological responses: comparison of shoulder and hip pressure relief

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yoon Jeong Baek ◽  
Seung-Hyun Kim ◽  
Sayup Kim ◽  
Eui-Sang Yoo ◽  
Joo-Young Lee
Keyword(s):  
Sleep Quality ◽  
Surface Pressure ◽  
Pressure Control ◽  
Body Region ◽  
High Quality ◽  
Pressure Relief ◽  
Content Type ◽  
Quality Sleep ◽  
Improve Sleep Quality

PurposeThe purpose of the present study was to evaluate the effect of air mattress pressure on sleep quality.Design/methodology/approachTen young healthy males participated in all hard surface [AH], shoulder soft [SS] and shoulder and hip soft mattress [SHS] conditions. The surface pressure for SS and SHS were set at their preferred levels.FindingsThe results showed that sleep efficiencies were over 95% for all the three conditions; there were no significant differences in individual sleep variables among the three conditions, but overall sleep quality was better for SS than AH (p = 0.065); heart rates during sleep was greater for AH than the other two conditions (p < 0.1); and a stronger relationship between clothing and bed microclimate humidity were found for SS and SHS than that for AH.Research limitations/implicationsThese results indicated that the both pressure relief air mattresses that were set at their own preferred levels provided high quality sleep with no marked differences.Practical implicationsAir pressure relief mattresses can improve sleep quality of healthy individuals during sleep at night. The results can be used to understand appropriate pressure distribution on surface mattress according to body region, and also to develop algorithms to provide optimum sleep using mattresses with surface pressure control by body region.Originality/valueThe present study found that the shoulder and/or hip pressure relief air mattresses that were set at their own preferred levels provided high quality sleep with no marked differences.

Investigations of improved cooling effectiveness for ramp film cooling with compound angle film cooling jets

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Krishna Anand Vasu Devan Nair Girija Kumari ◽  
Parammasivam Kanjikoil Mahali
Keyword(s):  
Film Cooling ◽  
Flat Surface ◽  
Flow Characteristics ◽  
Test Surface ◽  
Cooling Effectiveness ◽  
Content Type ◽  
Film Cooling Effectiveness ◽  
Ramp Test ◽  
Cooling Hole ◽  
Compound Angle

Purpose This paper aims to investigate the film cooling effectiveness (FCE) and mixing flow characteristics of the flat surface ramp model integrated with a compound angled film cooling jet. Design/methodology/approach Three-dimensional numerical simulation is performed on a flat surface ramp model with Reynolds Averaged Navier-Stokes approach using a finite volume solver. The tested model has a fixed ramp angle of 24° and a ramp width of two times the diameter of the film cooling hole. The coolant air is injected at 30° along the freestream direction. Three different film hole compound angles oriented to freestream direction at 0°, 90° and 180° were investigated for their performance on-ramp film cooling. The tested blowing ratios (BRs) are in the range of 0.9–2.0. Findings The film hole oriented at a compound angle of 180° has improved the area-averaged FCE on the ramp test surface by 86.74% at a mid-BR of 1.4% and 318.75% at higher BRs of 2.0. The 180° film hole compound angle has also produced higher local and spanwise averaged FCE on the ramp test surface. Originality/value According to the authors’ knowledge, this study is the first of its kind to investigate the ramp film cooling with a compound angle film cooling hole. The improved ramp model with a 180° film hole compound angle can be effectively applied for the end-wall surfaces of gas turbine film cooling.

Vortex formation on surging aerofoils with application to reverse flow modelling

2018 ◽  
Vol 859 ◽  
pp. 59-88 ◽  
Author(s):  
Philip B. Kirk ◽  
Anya R. Jones
Keyword(s):  
Surface Pressure ◽  
Reverse Flow ◽  
Vortex Formation ◽  
Three Dimensional ◽  
Tangential Velocity ◽  
Leading Edge ◽  
Field Measurements ◽  
Reduced Frequency ◽  
Advance Ratio ◽  
Convection Speed

The leading-edge vortex (LEV) is a powerful unsteady flow structure that can result in significant unsteady loads on lifting blades and wings. Using force, surface pressure and flow field measurements, this work represents an experimental campaign to characterize LEV behaviour in sinusoidally surging flows with widely varying amplitudes and frequencies. Additional tests were conducted in reverse flow surge, with kinematics similar to the tangential velocity profile seen by a blade element in recent high-advance-ratio rotor experiments. General results demonstrate the variability of LEV convection properties with reduced frequency, which greatly affected the average lift-to-drag ratio in a cycle. Analysis of surface pressure measurements suggests that LEV convection speed is a function only of the local instantaneous flow velocity. In the rotor-comparison tests, LEVs formed in reverse flow surge were found to convect more quickly than the corresponding reverse flow LEVs that form on a high-advance-ratio rotor, demonstrating that rotary motion has a stabilizing effect on LEVs. The reverse flow surging LEVs were also found to be of comparable strength to those observed on the high-advance-ratio rotor, leading to the conclusion that a surging-wing simplification might provide a suitable basis for low-order models of much more complex three-dimensional flows.

An investigation into the use of GAMA water tunnel for visualization of vortex breakdown on the delta wing

2018 ◽  
Author(s):  
Setyawan Bekti Wibowo ◽  
Sutrisno ◽  
Tri Agung Rohmat ◽  
Zainuri Anwar ◽  
Firdaus R. Syadi ◽  
...  
Keyword(s):  
Vortex Breakdown ◽  
Delta Wing ◽  
Water Tunnel
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