scholarly journals Effect of vortex generator on the flow field over a conventional delta wing in subsonic flow condition at higher angles of attack

2021 ◽  
Vol 49 (2) ◽  
pp. 395-400
Author(s):  
Manthan Patil ◽  
Rajesh Gawade ◽  
Shubham Potdar ◽  
Khushabu Nadaf ◽  
Sanoj Suresh ◽  
...  
Keyword(s):  
Flow Field ◽  
Flow Visualization ◽  
Drag Coefficient ◽  
Subsonic Flow ◽  
Delta Wing ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Vortex Generator ◽  
Oil Flow ◽  
Oil Flow Visualization

Flow over a conventional delta wing has been studied experimentally at a subsonic flow of 20 m/sec and the flow field developed at higher angle of attack varying from 10° to 20° has been captured. A vortex generator is mounted on the leeward surface of the delta wing and its effect on the flow field is studied. The set of wing tip vortices generated over the delta wing is captured by the oil flow visualization and the streamline over the delta wing surface captured with and without a vortex generator are compared. Based on the qualitative results, the effect of the vortex generator on the lift coefficient is anticipated. Further, force measurement is carried out to quantitatively analyze the effect of vortex generator on the lift and drag coefficient experienced by the delta wing and justify the anticipation made out of the qualitative oil flow visualization tests. In the present study, the effect of mounting of a vortex generator is found to be minimal on the lift coefficient experienced by the delta wing. However, a significant reduction in the drag coefficient with increase in angle of attack was observed by mounting a typical vortex generator.

scholarly journals Analysis on Flow Field Characteristics of Airfoil in Pitching Motion

2021 ◽  
Vol 2076 (1) ◽  
pp. 012069
Author(s):  
Rui Yin ◽  
Jing Huang ◽  
Zhi-Yuan He
Keyword(s):  
Flow Field ◽  
Drag Coefficient ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Decisive Role ◽  
Aerodynamic Characteristics ◽  
Pitching Motion ◽  
Maximum Value ◽  
Flow Field Characteristics ◽  
Lift And Drag

Abstract Based on CFD, the flow field characteristics of NACA4412 airfoil are analyzed under pitching motion, and its aerodynamic characteristics are interpreted. The results show that streamline changes on the upper surface of the airfoil play a decisive role in the aerodynamic characteristics. The interaction between the vortex leads to fluctuations in the lift and drag coefficients. Under a big angle of attack, the secondary trailing vortex on the upper surface of the airfoil adheres to the trailing edge of the airfoil, resulting in an increased drag coefficient. Under a small angle of attack, the secondary trailing vortex can break away from the airfoil. The lift coefficient reaches the maximum value of 2.961 before the airfoil is turned upside down, and the drag coefficient reaches the maximum value of 1.515 after the airfoil is turned upside down, but the corresponding angles of attack of the two are equal.

scholarly journals ANALISIS CFD KARAKTERISTIK AERODINAMIKA PADA SAYAP PESAWAT LSU-05 DENGAN PENAMBAHAN VORTEX GENERATOR (ANALYSIS OF CFD AERODYNAMIC CHARACTERISTICS AT THE WING OF AIRCRAFT LSU-05 WITH THE ADDITION OF VORTEX GENERATOR)

2017 ◽  
Vol 15 (1) ◽  
pp. 45
Author(s):  
Awalu Romadhon ◽  
Dana Herdiana
Keyword(s):  
Drag Coefficient ◽  
Cfd Simulation ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Vortex Generator ◽  
Aerodynamic Characteristics ◽  
Unmanned Aircraft ◽  
Vortex Generators ◽  
Aircraft Wing ◽  
Ansys Fluent

LSU-05 aircraft is one of the unmanned aerial vehicles (UAV), which is being developed by the Aeronautics Technology Center of LAPAN, whose mission is for research, observation, patrol, border surveillance, and investigation of natural disasters. This study aims to determine the effect of vortex generators on the aerodynamic characteristics of the LSU-05 Unmanned Aircraft wing. The method used is a numerical analysis with CFD simulation for predicting aerodynamic characteristics and flow phenomena that occur. The models used are the aircraft wing of the LSU-05 without vortex generator and with vortex generator designed with CATIA software. The simulation is using ANSYS Fluent software to determine changes in the aerodynamic characteristics of the wing after the addition of vortex generators such as the lift coefficient and drag coefficient. The results of the addition of vortex generator on LSU-05 wings are the increasing value of the maximum lift coefficient of the wing which becomes 1,34840 from 1,26450, it increases 0,0839 (6.63%) point, the increasing value of the drag coefficient on the angle of attack from -9⁰ to 11⁰, the decreasing value of the drag coefficient on the angle of attack 12⁰ up to 15⁰ and the increasing stall angle of wing from 11⁰ to 14⁰ or increased by 3⁰ (27,7%). AbstrakPesawat LSU-05 adalah salah satu pesawat tanpa awak (UAV) yang sedang dikembangkan oleh Pusat Teknologi Penerbangan LAPAN, yang mempunyai misi untuk kegiatan penelitian, observasi, patroli, pengawasan perbatasan wilayah, dan investigasi bencana alam. Penelitian ini bertujuan untuk mengetahui pengaruh penambahan vortex generator terhadap karakteristik aerodinamika dari sayap Pesawat Tanpa Awak LSU-05. Metode yang digunakan adalah analisis numerik dengan simulasi CFD untuk memprediksi karakteristik aerodinamika dan fenomena aliran yang terjadi. Model yang digunakan adalah sayap pesawat LSU-05 tanpa vortex generator dan dengan vortex generator yang didesain dengan software CATIA. Simulasi menggunakan software ANSYS Fluent untuk mengetahui perubahan karakteristik aerodinamika sayap setelah penambahan vortex generator seperti koefisien lift dan koefisien drag. Hasil yang diperoleh dari penelitian penambahan vortex generator pada sayap Pesawat LSU-05 adalah peningkatan nilai koefisien lift maksimum sayap dari 1,26450 menjadi 1,34840 atau naik sebesar 0,0839 (6,63%), peningkatan nilai koefisien drag pada sudut serang -9⁰ s/d 11⁰, penurunan nilai koefisien drag pada sudut serang 12⁰ s.d 15⁰ dan peningkatan sudut stall sayap dari 11⁰ menjadi 14⁰ atau naik sebesar 3⁰ (27,7 %).

scholarly journals Experimental Study on Plasma Flow Control of Symmetric Flying Wing Based on Two Kinds of Scaling Models

Symmetry ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1261
Author(s):  
Xie ◽  
Liang ◽  
Han ◽  
Niu ◽  
Wei ◽  
...  
Keyword(s):  
Flow Field ◽  
Drag Coefficient ◽  
Plasma Flow ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Discharge Energy ◽  
Scaling Models ◽  
Plasma Flow Control ◽  
Stall Angle ◽  
Microsecond Pulse

The symmetric flying wing has a simple structure and a high lift-to-drag ratio. Due to its complicated surface design, the flow field flowing through its surface is also complex and variable, and the three-dimensional effect is obvious. In order to verify the effect of microsecond pulse plasma flow control on the symmetric flying wing, two different sizes of scaling models were selected. The discharge energy was analyzed, and the force and moment characteristics of the two flying wings and the particle image velocimetry (PIV) results on their surface flow field were compared to obtain the following conclusions. The microsecond pulse surface dielectric barrier discharge energy density is independent of the actuator length but increases with the actuation voltage. After actuation, the stall angle of attack of the small flying wing is delayed by 4°, the maximum lift coefficient is increased by 30.9%, and the drag coefficient can be reduced by 17.3%. After the large flying wing is actuated, the stall angle of attack is delayed by 4°, the maximum lift coefficient is increased by 15.1%, but the drag coefficient is increased. The test results of PIV in the flow field of different sections indicate that the stall separation on the surface of the symmetric flying wing starts first from the outer side, and then the separation area begins to appear on the inner side as the angle of attack increases.

Experimental investigation of plasma vortex generator in flow control

2018 ◽  
Vol 92 (3) ◽  
pp. 376-385
Author(s):  
Alireza Ghayour ◽  
Mahmoud Mani
Keyword(s):  
Vortex Generator ◽  
Leading Edge ◽  
Streamwise Vortex ◽  
Flow Visualisation ◽  
Content Type ◽  
Oil Flow ◽  
Order Of Magnitude ◽  
Oil Flow Visualization ◽  
Unsteady Operation ◽  
Naca 0012

Purpose The purpose of this paper is to compare the effects of two different configurations of plasma streamwise vortex generators (PSVG), including comb-type and mesh-type in controlling flow. This is demonstrated on the NACA 0012 airfoil. Design/methodology/approach The investigations have been done experimentally at the various electric and aerodynamic conditions. The surface oil flow visualization method has been used to the better understanding of the flow physics and the interaction of the oncoming flow passing over the airfoil and the vortex generated by comb-type PSVG. Findings This paper demonstrates the potential capabilities of the mesh-type and comb-type PSVGs in controlling flow in unsteady operation. It was found that the vortex generated by the mesh-type PSVG in unsteady operation was an order of magnitude stronger than comb-type PSVG. The flow visualisation technic proved that only a part of the plasma actuator is effective in the condition that the actuator is installed only on a portion of the upper surface of the airfoil. Originality/value This paper experimentally confirms the capabilities of the mesh-type PSVG unsteady operation in compare with comb-type PSVG in controlling flow, whereby recommends using mesh-type PSVG in the leading edge in front of comb-type PSVG on the entire wingspan to prevent the stall.

scholarly journals Numerical investigation of the low-frequency flow oscillation over a NACA-0012 aerofoil at the inception of stall

2019 ◽  
Vol 11 ◽  
pp. 175682931983368 ◽  
Author(s):  
Yasir A ElAwad ◽  
Eltayeb M ElJack
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Separation Bubble ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Low Frequency ◽  
Laminar Separation Bubble ◽  
Flow Oscillation ◽  
Laminar Separation ◽  
Naca 0012

High-fidelity large eddy simulation is carried out for the flow field around a NACA-0012 aerofoil at Reynolds number of [Formula: see text], Mach number of 0.4, and various angles of attack around the onset of stall. The laminar separation bubble is formed on the suction surface of the aerofoil and is constituted by the reattached shear layer. At these conditions, the laminar separation bubble is unstable and switches between a short bubble and an open bubble. The instability of the laminar separation bubble triggers a low-frequency flow oscillation. The aerodynamic coefficients oscillate accordingly at a low frequency. The lift and the drag coefficients compare very well to recent high-accuracy experimental data, and the lift leads the drag by a phase shift of [Formula: see text]. The mean lift coefficient peaks at the angle of attack of [Formula: see text], in total agreement with the experimental data. The spectra of the lift coefficient does not show a significant low-frequency peak at angles of attack lower than or equal the stall angle of attack ([Formula: see text]). At higher angles of attack, the spectra show two low-frequency peaks and the low-frequency flow oscillation is fully developed at the angle of attack of [Formula: see text]. The behaviour of the flow-field and changes in the turbulent kinetic energy over one low-frequency flow oscillation cycle are described qualitatively.

scholarly journals Three-Dimensional CFD Analysis of the Hand and Forearm in Swimming

2011 ◽  
Vol 27 (1) ◽  
pp. 74-80 ◽  
Author(s):  
Daniel A. Marinho ◽  
António J. Silva ◽  
Victor M. Reis ◽  
Tiago M. Barbosa ◽  
João P. Vilas-Boas ◽  
...  
Keyword(s):  
Drag Coefficient ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Three Dimensional ◽  
Force Production ◽  
Realistic Model ◽  
Hydrodynamic Characteristics ◽  
Force Coefficient ◽  
Commercial Code ◽  
Dimensional Domain

The purpose of this study was to analyze the hydrodynamic characteristics of a realistic model of an elite swimmer hand/forearm using three-dimensional computational fluid dynamics techniques. A three-dimensional domain was designed to simulate the fluid flow around a swimmer hand and forearm model in different orientations (0°, 45°, and 90° for the three axes Ox, Oy and Oz). The hand/forearm model was obtained through computerized tomography scans. Steady-state analyses were performed using the commercial code Fluent. The drag coefficient presented higher values than the lift coefficient for all model orientations. The drag coefficient of the hand/forearm model increased with the angle of attack, with the maximum value of the force coefficient corresponding to an angle of attack of 90°. The drag coefficient obtained the highest value at an orientation of the hand plane in which the model was directly perpendicular to the direction of the flow. An important contribution of the lift coefficient was observed at an angle of attack of 45°, which could have an important role in the overall propulsive force production of the hand and forearm in swimming phases, when the angle of attack is near 45°.

Studies of Flow Topology around Hemisphere at Transonic Speeds Using Time-Resolved Oil Flow Visualization

2016 ◽  
Author(s):  
Stanislav Gordeyev ◽  
Alexander Vorobiev ◽  
Eric J. Jumper ◽  
Sivaram P. Gogineni ◽  
Donald J. Wittich
Keyword(s):  
Flow Visualization ◽  
Flow Topology ◽  
Time Resolved ◽  
Oil Flow ◽  
Oil Flow Visualization

Film-Cooled Turbine Endwall in a Transonic Flow Field: Part I—Aerodynamic Measurements

2001 ◽  
Vol 123 (4) ◽  
pp. 709-719 ◽  
Author(s):  
Friedrich Kost ◽  
Martin Nicklas
Keyword(s):  
Flow Field ◽  
Transonic Flow ◽  
Film Cooling ◽  
Coolant Flow ◽  
Pressure Probe ◽  
Thermal Methods ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Oil Flow ◽  
Oil Flow Visualization

Thermodynamic and aerodynamic measurements were carried out in a linear turbine cascade with transonic flow field. Heat transfer and adiabatic film-cooling effectiveness resulting from the interaction of the flow field and the ejected coolant at the endwall were measured and will be discussed in two parts. The investigations were performed in the Windtunnel for Straight Cascades (EGG) at DLR, Go¨ttingen. The film-cooled NGV endwall was operated at representative dimensionless engine conditions of Mach and Reynolds number Ma2is=1.0 and Re2=850,000 respectively. Part I of the investigation discusses the aerodynamic measurements. Detailed aerodynamic measurements were carried out in the vicinity of a turbine stator endwall using conventional pressure measurements and a Laser-2-Focus (L2F) device. The L2F served as a velocimeter measuring 2D-velocity vectors and turbulence quantities and as a tool to determine the concentration of coolant ejected through a slot and through holes at the endwall. Pressure distribution measurements provided information on the endwall pressure field and its variation with coolant flow rate. Pressure probe measurements delivered cascade performance data. Oil flow visualization and laser velocimetry gave a picture of the near endwall flow field and its interference with the coolant. A strikingly strong interaction of coolant air and secondary flow field could be identified. The measurement of coolant concentration downstream of the ejection locations provided a detailed picture of the coolant flow convection and its mixing with the main flow. The relative coolant concentration in the flow field is directly comparable to the adiabatic film-cooling effectiveness measured by thermal methods at the wall.

Experimental Aerodynamic Characteristics of a Compound Wing in Ground Effect

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Saeed Jamei ◽  
Adi Maimun Abdul Malek ◽  
Shuhaimi Mansor ◽  
Nor Azwadi Che Sidik ◽  
Agoes Priyanto
Keyword(s):  
Reynolds Number ◽  
Drag Coefficient ◽  
Center Of Pressure ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Leading Edge ◽  
Ground Effect ◽  
Reynolds Numbers ◽  
Aerodynamic Characteristics ◽  
Ground Clearance

Wing configuration is a parameter that affects the performance of wing-in-ground effect (WIG) craft. In this study, the aerodynamic characteristics of a new compound wing were investigated during ground effect. The compound wing was divided into three parts with a rectangular wing in the middle and two reverse taper wings with anhedral angle at the sides. The sectional profile of the wing model is NACA6409. The experiments on the compound wing and the rectangular wing were carried to examine different ground clearances, angles of attack, and Reynolds numbers. The aerodynamic coefficients of the compound wing were compared with those of the rectangular wing, which had an acceptable increase in its lift coefficient at small ground clearances, and its drag coefficient decreased compared to rectangular wing at a wide range of ground clearances, angles of attack, and Reynolds numbers. Furthermore, the lift to drag ratio of the compound wing improved considerably at small ground clearances. However, this improvement decreased at higher ground clearance. The drag polar of the compound wing showed the increment of lift coefficient versus drag coefficient was higher especially at small ground clearances. The Reynolds number had a gradual effect on lift and drag coefficients and also lift to drag of both wings. Generally, the nose down pitching moment of the compound wing was found smaller, but it was greater at high angle of attack and Reynolds number for all ground clearance. The center of pressure was closer to the leading edge of the wing in contrast to the rectangular wing. However, the center of pressure of the compound wing was later to the leading edge at high ground clearance, angle of attack, and Reynolds number.

Sign in / Sign up

Export Citation Format

Share Document