scholarly journals Investigations of Lift and Drag Performances on Neo-Ptero Micro UAV Models

2021 ◽  
Vol 84 (2) ◽  
pp. 50-62
Author(s):  
Noor Iswadi Ismail ◽  
Mahamad Hisyam Mahamad Basri ◽  
Hazim Sharudin ◽  
Zurriati Mohd Ali ◽  
Ahmad Aliff Ahmad Shariffuddin ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Lift Coefficient ◽  
Successful Development ◽  
Aerodynamic Efficiency ◽  
Trade Off ◽  
Flight Stability ◽  
Stall Angle ◽  
Lift And Drag ◽  
Lift And Drag Coefficient

This paper presents the investigation and improvement of lift and drag characteristics of Neo-Ptero micro-UAV models based on the virtual wind tunnel method. Despite its successful development and flight stability, the lift and drag coefficients characteristics of the current Mark 1 Neo-Ptero remain unknown. To improve the Mark 1 Neo-Ptero performances, Mark 2 Neo-Ptero model has given a new unsymmetrical airfoil wing configuration. The computational aerodynamic analysis was executed and focused on certain lift and drag coefficient characteristics. Lift coefficient results showed that Mark 2 improved in overall lift characteristics such as zero-lift angle, maximum lift magnitude and stall angle magnitude. Conversely, Mark 2 model suffered a slightly higher drag coefficient magnitude and more significant drag increment percentage than Mark 1. However, the trade-off between superior lift magnitude and minor drag generation induced by Mark 2 boosts the model’s aerodynamic efficiency performances but is only limited at early angle stages.

scholarly journals Experimental and Computational Investigation of Spoiler Deployment on Wing Stall

2021 ◽  
Author(s):  
Scott Lindsay
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Computational Study ◽  
Lift Coefficient ◽  
Wind Tunnel Experiment ◽  
Chord Length ◽  
Aerodynamic Efficiency ◽  
Stall Angle ◽  
Wing Stall ◽  
High Angles Of Attack

Upper surface flaps commonly referred to as spoilers or drag brakes can increase maximum lift, and improve aerodynamic efficiency at high, near-stall angles of attack. This phenomenon was studied experimentally and computationally using a 0.307626 m chord length NACA 2412 airfoil in six different configurations, and one baseline clean configuration. A wind tunnel model was placed in the Ryerson Low Speed Wind Tunnel (atmospheric, closed-circuit, 3 ft × 3 ft test section) at a Reynold’s number of approximately 780,000 and a Mach number of 0.136. The wind tunnel study increased the lift coefficient by 0.393%-2.497% depending on the spoiler configuration. A spoiler of 10% chord length increased the maximum lift coefficient by 2.497 % when deflected 8º, by 2.110% when deflected 15º, and reduced the maximum lift coefficient by 2.783% when deflected 25º. A spoiler of 15% chord length produced smaller maximum lift coefficient gains; 0.393% when deflected 8º, by 1.760% when deflected 15º, and reduced the maximum lift coefficient by 4.475% when deflected 25º. Deflecting the spoiler increased the stall angle between 37.658% and 87.544% when compared with the clean configuration. The drag coefficient of spoiler configurations was lower than the clean configuration at angles of attack above 18º. The combination of the increased lift and reduced drag at angles of attack above 18º created by the spoiler configurations resulted in a higher aerodynamic efficiency than the clean configuration case. A 10% chord length spoiler deflected at 8º produced the highest aerodynamic efficiency gains. At low angles of attack, the computational study produced consistently higher lift coefficients compared with the wind tunnel experiment. The lift-slope was consistent with the wind tunnel experiment lift-slope. The spoiler airfoil stall behaviour was inconsistent with the results from the wind tunnel experiment. The drag coefficient results were consistent with the wind tunnel experiment at low angles of attack. However, the spoiler equipped airfoils did not reduce drag at high angles of attack. Therefore, the computational model was not valid for the spoiler configurations at high angles of attack.

scholarly journals Experimental and Computational Investigation of Spoiler Deployment on Wing Stall

2021 ◽  
Author(s):  
Scott Lindsay
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Computational Study ◽  
Lift Coefficient ◽  
Wind Tunnel Experiment ◽  
Chord Length ◽  
Aerodynamic Efficiency ◽  
Stall Angle ◽  
Wing Stall ◽  
High Angles Of Attack

Upper surface flaps commonly referred to as spoilers or drag brakes can increase maximum lift, and improve aerodynamic efficiency at high, near-stall angles of attack. This phenomenon was studied experimentally and computationally using a 0.307626 m chord length NACA 2412 airfoil in six different configurations, and one baseline clean configuration. A wind tunnel model was placed in the Ryerson Low Speed Wind Tunnel (atmospheric, closed-circuit, 3 ft × 3 ft test section) at a Reynold’s number of approximately 780,000 and a Mach number of 0.136. The wind tunnel study increased the lift coefficient by 0.393%-2.497% depending on the spoiler configuration. A spoiler of 10% chord length increased the maximum lift coefficient by 2.497 % when deflected 8º, by 2.110% when deflected 15º, and reduced the maximum lift coefficient by 2.783% when deflected 25º. A spoiler of 15% chord length produced smaller maximum lift coefficient gains; 0.393% when deflected 8º, by 1.760% when deflected 15º, and reduced the maximum lift coefficient by 4.475% when deflected 25º. Deflecting the spoiler increased the stall angle between 37.658% and 87.544% when compared with the clean configuration. The drag coefficient of spoiler configurations was lower than the clean configuration at angles of attack above 18º. The combination of the increased lift and reduced drag at angles of attack above 18º created by the spoiler configurations resulted in a higher aerodynamic efficiency than the clean configuration case. A 10% chord length spoiler deflected at 8º produced the highest aerodynamic efficiency gains. At low angles of attack, the computational study produced consistently higher lift coefficients compared with the wind tunnel experiment. The lift-slope was consistent with the wind tunnel experiment lift-slope. The spoiler airfoil stall behaviour was inconsistent with the results from the wind tunnel experiment. The drag coefficient results were consistent with the wind tunnel experiment at low angles of attack. However, the spoiler equipped airfoils did not reduce drag at high angles of attack. Therefore, the computational model was not valid for the spoiler configurations at high angles of attack.

Drag and lift measurements of solid sports balls in still air

2017 ◽  
Vol 232 (3) ◽  
pp. 255-263 ◽  
Author(s):  
Jeff R Kensrud ◽  
Lloyd V Smith
Keyword(s):  
Surface Roughness ◽  
Wind Tunnel ◽  
Drag Coefficient ◽  
Rough Surface ◽  
Lift Coefficient ◽  
Laboratory Setting ◽  
Air Drag ◽  
High Speeds ◽  
Drag And Lift ◽  
Lift And Drag

The following article considers lift and drag measurements of solid sports balls propelled through still air in a laboratory setting. The balls traveled at speeds ranging from 26 to 134 m/s with spin rates up to 3900 r/min. Light gates measured the speed and location of the balls at two locations from which lift and drag values were determined. Ball roughness varied from polished to rough surface protrusions, that is, seams as high as 1.5 mm. Lift and drag were observed to depend on speed, spin rate, surface roughness, and seam orientation. A drag crisis was observed on smooth balls as well as non-rotating seamed balls with seam heights less than 0.9 mm. The drag coefficient of approximately 0.42 was nearly constant with speed for spinning seamed balls with seam height greater than 0.9 mm. The still air drag coefficient of smooth balls was comparable to wind tunnel drag at low speeds ( Re < 2 × 105) and higher than wind tunnel results at high speeds ( Re > 2 × 105). The lift and drag coefficients of spinning balls increased with increasing spin rate. The lift coefficient of baseballs was not sensitive to ball orientation or seam height.

Effects of surface flow visualisation on aerodynamic loads at low Reynolds number

2015 ◽  
Vol 119 (1215) ◽  
pp. 663-672
Author(s):  
L. W. Traub ◽  
R. Waghela ◽  
E. M. Botero
Keyword(s):  
Drag Coefficient ◽  
Lift Coefficient ◽  
Time History ◽  
Surface Flow ◽  
Flow Visualisation ◽  
Distribution Method ◽  
History Of ◽  
Low Reynolds ◽  
Lift And Drag ◽  
Lift And Drag Coefficient

AbstractIn this article, the effect of on-surface flow visualisation (SVF) techniques on measured loads over an airfoil are explored. Titanium dioxide based mixture effects on the lift and drag coefficient are experimentally quantified at low Reynolds numbers by recording the time history as the patterns evolve and freeze. With statistical comparison based on Student’s t-distribution method, it was determined that the effect on the drag coefficient was minimal but the lift coefficient was slightly attenuated. Additionally, it was observed that at high angles-of-attack the temporal history of the flow as the wind tunnel ramps up may alter the steady-state flow field in the presence of a SFV mixture.

scholarly journals Numerical Analysis of the Aerodynamic Characteristics of NACA-4312 Airfoil

2020 ◽  
Vol 01 (02) ◽  
pp. 29-36
Author(s):  
Md Rhyhanul Islam Pranto ◽  
Mohammad Ilias Inam
Keyword(s):  
Reynolds Number ◽  
Drag Coefficient ◽  
Lift Coefficient ◽  
Turbulence Models ◽  
Aerodynamic Characteristics ◽  
Numerical Results ◽  
Ansys Fluent ◽  
Coefficient Increase ◽  
Lift And Drag ◽  
Lift And Drag Coefficient

The aim of the work is to investigate the aerodynamic characteristics such as lift coefficient, drag coefficient, pressure distribution over a surface of an airfoil of NACA-4312. A commercial software ANSYS Fluent was used for these numerical simulations to calculate the aerodynamic characteristics of 2-D NACA-4312 airfoil at different angles of attack (α) at fixed Reynolds number (Re), equal to 5×10^5 . These simulations were solved using two different turbulence models, one was the Standard k-ε model with enhanced wall treatment and other was the SST k-ω model. Numerical results demonstrate that both models can produce similar results with little deviations. It was observed that both lift and drag coefficient increase at higher angles of attack, however lift coefficient starts to reduce at α =13° which is known as stalling condition. Numerical results also show that flow separations start at rare edge when the angle of attack is higher than 13° due to the reduction of lift coefficient.

scholarly journals A Research on Wind Tunnel on Drag Reduction in Aircraft Wing by Inducing Surface Roughness

2019 ◽  
Vol 8 (2S3) ◽  
pp. 25-28
Keyword(s):  
Surface Roughness ◽  
Wind Tunnel ◽  
Viscous Drag ◽  
Friction Drag ◽  
Aircraft Wing ◽  
Aerodynamic Efficiency ◽  
Stall Angle ◽  
Lift And Drag ◽  
Naca 0012 ◽  
Inducing Surface

Drag is a major issue that aircraft industries are facing today. Innumerable investigations are in progress which mainly focus on the methods to reduce drag. Improving the aerodynamic efficiency of the vehicle can resolve this drawback to a great extent. The aerodynamic efficiency is explained in L/D ratio, decreasing the drag component will increase the aerodynamic efficiency. In this research a methodology to reduce the drag by creating roughness over wing surface has been adopted. By adopting this surface roughness method, the transition of the air flow from the laminar to the turbulent region will result in less drag. This research is being carried out based on the above said theory. The outcome of this method can delay the flow separation in a wing which helps in increasing the lift. The roughness has reduced the coefficient of skin friction drag or viscous drag and increased the coefficient of lift along with the stall angle of attack. NACA 0012 airfoil was selected for this study. Aluminum wing models are fabricated with and without surface roughness and same has been tested in Wind Tunnel. The results are discussed in terms of Lift and Drag

scholarly journals The Effect of Spoiler Shape and Setting Angle on Racing Cars Aerodynamic Performance

2020 ◽  
Vol 5 (1) ◽  
pp. 11-20
Author(s):  
Hesam Eftekhari ◽  
Abdulkareem Sh. Mahdi Al-Obaidi ◽  
Shahrooz Eftekhari
Keyword(s):  
Drag Coefficient ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Ansys Fluent ◽  
Aerodynamic Efficiency ◽  
Race Car ◽  
Setting Angle ◽  
Being There ◽  
Lift And Drag ◽  
Lift And Drag Coefficient

Automotive racing is one of the favorite sports of human being. There have been many developments in past decades by car engineers to improve the performance of the engine and increase the aerodynamic efficiency of the race cars to achieve a better lap time and get a better placement safely. One of the ways to improve the aerodynamic performance of a race car is to use rear spoilers. This study by using ANSYS FLUENT numerically investigated the effect of the spoiler shape and setting angle on the aerodynamic characteristics of a race car and then it was validated by conducting wind tunnel experiment. Lift and drag coefficient of NACA0012, NACA4412, and S1223 are determined in Reynold’s number of 2×105 as an airfoil and as spoiler on ERC model which is a conceptual car model inspired by Porsche 911. It was found that ERC model with spoiler would have better aerodynamic efficiency compared to ERC model without spoiler. Also, S1223 at -6 degrees was identified as the optimized configuration as it generates the highest downforce. Even though the drag coefficient at this setting angle is slightly higher, but in terms of stability and handling IT is at its best. Overall, this study would help car manufacturers, for racing and commercial purposes, to have a better insight into the effect of spoiler configuration on the aerodynamic performance of cars. Hence, the stability, handling, and efficiency of the cars can be further improved by selecting the suitable spoiler configuration.

Numerical Simulation of Flow Control on Marine Riser With Attached Splitter Plate

2010 ◽  
Author(s):  
Jiasong Wang ◽  
Hua Liu ◽  
Fei Gu ◽  
Pengliang Zhao
Keyword(s):  
Numerical Simulation ◽  
Flow Control ◽  
Drag Coefficient ◽  
Lift Coefficient ◽  
Splitter Plate ◽  
Hydrodynamic Characteristics ◽  
Control Effect ◽  
Long Time ◽  
Lift And Drag ◽  
Lift And Drag Coefficient

Attaching a splitter plate (SP) on the base of a riser wall is used to control the flow of risers and evaluated by using the CFD technique in this paper. A finite-volume total variation diminishing (TVD) approach for solving incompressible turbulent flow with renormalization group (RNG) turbulence model was used to simulate the hydrodynamic characteristics of the riser system with additional SP for the different aspect ratio of length to diameter L/D. It was shown that the present numerical method has high order of accuracy by comparing with the available experimental and numerical simulation data for typical circular cylinder flow. A riser system attached with SPs of L/D = 0.5∼2.0 for Reynolds number 1000, and 30000 respectively can obviously reduce the lift and drag coefficient and alter the vortex shedding frequency. The mean drag coefficient can be reduced up to 20% and 35% and the maximum lift coefficient can be reduced up to 94% and 97%, for Re = 1000 and 30000, respectively. The lift can be effectively suppressed after a relative long time. L/D = 0.5∼1.0 may be considered as more practical geometries considering the real conditions, which also have good flow control effect.

Alula-Inspired Leading Edge Device for Low Reynolds Number Flight

2016 ◽  
Author(s):  
Boris A. Mandadzhiev ◽  
Michael K. Lynch ◽  
Leonardo P. Chamorro ◽  
Aimy A. Wissa
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Drag Coefficient ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Tip Vortex ◽  
Relative Angle ◽  
Lift And Drag

Robust and predictable aerodynamic performance of unmanned aerial vehicles at the limits of their design envelope is critical for safety and mission adaptability. In order for a fixed wing aircraft to maintain the lift necessary for sustained flight at very low speeds and large angles of attack (AoA), the wing shape has to change. This is often achieved by using deployable aerodynamic surfaces, such as flaps or slats, from the wing leading or trailing edges. In nature, one such device is a feathered structure on birds’ wings called the alula. The span of the alula is 5% to 20% of the wing and is attached to the first digit of the wing. The goal of the current study is to understand the aerodynamic effects of the alula on wing performance. A series of wind tunnel experiments are performed to quantify the effect of various alula deployment parameters on the aerodynamic performance of a cambered airfoil (S1223). A full wind tunnel span wing, with a single alula located at the wing mid-span is tested under uniform low-turbulence flow at three Reynolds numbers, Re = 85,000, 106,00 and 146,000. An experimental matrix is developed to find the range of effectiveness of an alula-type device. The alula relative angle of attack measured measured from the mean chord of the airfoil is varied to modulate tip-vortex strength, while the alula deflection is varied to modulate the distance of the tip vortex to the wing surface. Lift and drag forces were measured using a six axis force transducer. The lift and drag coefficients showed the greatest sensitivity to the the alula relative angle of attack, increasing the normalized lift coefficient by as much as 80%. Improvements in lift are strongly correlated to higher alula angle, with β = 0° – 5°, while reduction in the drag coefficient is observed with higher alula tip deflection ratios and lower β angles. Results show that, as the wing angle of attack and Reynolds number are increased, the overall lift co-efficient improvement is diminished while the reduction in drag coefficient is higher.

Numerical Analysis of Water Suction Effect on Lift and Drag Coefficient of a Hydrofoil With Cavitation

2009 ◽  
Author(s):  
Mohammad J. Izadi
Keyword(s):  
Drag Coefficient ◽  
Mass Flow ◽  
Static Pressure ◽  
Turbulent Viscosity ◽  
Lift Coefficient ◽  
Vapor Bubbles ◽  
Cloud Cavitation ◽  
Lift And Drag ◽  
Lift And Drag Coefficient ◽  
Unsteady Cavitating Flow

Cavitation is the formation of the vapor bubbles within a liquid where the flow dynamics, cause the local static pressure to drop below the vapor pressure. This phenomenon can cause undesirable effects on the hydrofoils such as a decrease in the lift and an increase in the drag. In the present study, the unsteady cavitating flow over a 3-D hydrofoil is numerically simulated. The purpose of this work is to investigate the effect of the upper surface suction in the cavitation area on the lift and drag coefficients of a hydrofoil. An unsteady uniform flow of water over a 3-D NACA hydrofoil is numerically simulated. The full cavitation model along with the RNG k-ε turbulence model is implemented. A modification to the turbulent viscosity, which is necessary to simulate the cloud cavitation, is implemented. The simulation is implemented for various angles of attack and various suction velocities. Comparison between some experimental data and the numerical simulation obtained here is done in order to validate the numerical results. The results obtained here show that, as the mass flow of the water suction increases, the drag coefficient is decreased for large angles of attack, but for small angles of attack it does not change as much. As the mass flow of the water suction increases, the lift coefficient is decreased for small angles of attack and for larger angles of attack the lift coefficient is increased.

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