The Effect of Intake and Exhaust on the Two-Dimensional Airfoil in a Distributed Propulsion System

2016 ◽  
Author(s):  
Yongsheng Wang ◽  
Ming Zhou ◽  
Quanyong Xu
Keyword(s):  
Lift Coefficient ◽  
Leading Edge ◽  
Jet Flow ◽  
Propulsion System ◽  
Two Dimensional ◽  
Original Design ◽  
Trailing Edge ◽  
Distributed Propulsion ◽  
Drag Ratio

A new distributed propulsion system in which micro-engines were embedded into the wings was proposed. To consider the effects of the intake and exhaust of the engines, the system was simplified as a two-dimensional airfoil with a surface ingestion and a trailing edge jet. The influence of the layout was comprehensively studied with CFD. Compared to the original design, the surface ingestion and trailing edge jet can increase the lift coefficient. The lift-drag ratio increases at smaller attack angles (< 3°) and decreases at greater attack angles (> 3°). The lift-drag ratio improvement with surface ingestion at the leading edge is mainly due to the drop in drag, while the increase with ingestion close to the trailing edge is primarily because of the augment of lift. Moreover, increasing the temperature of the jet flow can enlarge the range of the attack angles with a higher lift-drag ratio.

Aerodynamic Performance of Blended Wing Body Aircraft with Distributed Propulsion

2014 ◽  
Vol 1016 ◽  
pp. 354-358 ◽  
Author(s):  
Wan Fang Yan ◽  
Jiang Hao Wu ◽  
Yan Lai Zhang
Keyword(s):  
Lift Coefficient ◽  
Large Angle ◽  
Aerodynamic Performance ◽  
Propulsion System ◽  
System Configuration ◽  
High Lift ◽  
Distributed Propulsion ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Center Body

A 350-passenger BWB with a distributed propulsion system configuration is carried out and its aerodynamic performance in cruising and taking off are analyzed and discussed. It is shown from computation that the integrated configuration has a commendable aerodynamic performance in cruising and taking off. The cruise lift to drag ratio is reach to 24.0 in cruising. The ingestion effect of the propulsion system leads to a high lift at a low speed. The maximum lift coefficient CLmax is 1.62 when α=20° in taking off. In addition, the ingestion also delays the flow separation on the upper surface of center body, which contributes to a well stall performance of the configuration at large angle of attack.

scholarly journals Influences of distributed propulsion system parameters on aerodynamic characteristics of a BLI-BWB UAV

2021 ◽  
Vol 39 (1) ◽  
pp. 17-26
Author(s):  
Yang Zhang ◽  
Zhou Zhou ◽  
Kelei Wang ◽  
Zhongyun Fan
Keyword(s):  
Lift Coefficient ◽  
Aerodynamic Characteristics ◽  
Propulsion System ◽  
Navier Stokes ◽  
System Parameters ◽  
Ducted Fan ◽  
Distributed Propulsion ◽  
Air Flow Velocity ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Focusing on the aerodynamic characteristics of the blended wing body (BWB) aircraft with boundary layer ingestion(BLI) distributed propulsion system; the influences of propulsion system parameters under the condition of cruise and takeoff are studied. Firstly, based on the momentum source method (MSM), the NASA ducted propeller model is simulated, which verifies the reliability of the numerical method in this paper. Then, by using the method of structural grid and S-A turbulence model to solve the Reynolds averaged Navier-Stokes (RANS) equation, the aerodynamic characteristics of the BLI UAV model with D80 ducted fan in cruise state are numerically calculated. It is proved that the advantage of the BLI distributed propulsion system is superior in increasing lift. And the aerodynamic characteristics of the BLI UAV with different propulsion system parameters are compared. At last, the aerodynamic effect of ducted fan thrust on the BLI UAV is carried out. The results show that, due to the suction function of the BLI distributed propulsion system, the air flow velocity near the BWB fuselage is effectively accelerated, and the flow along the spanwise is restrained, which improves the lift coefficient about 16% and lift-to-drag ratio about 10%. Under the condition of equal thrust, the D80 ducted fan brings larger load of the propeller, which makes the static pressure at the inlet and outlet smaller. Compared with D150 ducted fan, the lift-to-drag ratio is increased by 15%. When aircraft takes off, increasing the thrust of the ducted fan can reduce the possibility of flow separation on the upper surface of the fuselage, which is conducive to the safety.

Elliptic Airfoil Stall Analysis With Trailing Edge Slots

2010 ◽  
Author(s):  
Jonathan Kweder ◽  
Mary Ann Clarke ◽  
James E. Smith
Keyword(s):  
Lift Coefficient ◽  
Leading Edge ◽  
Surface Velocity ◽  
Circulation Control ◽  
West Virginia University ◽  
Trailing Edge ◽  
Near Surface ◽  
Wind Speeds ◽  
Edge Location ◽  
Stall Angle

Circulation control (CC) is a high-lift methodology that can be used on a variety of aerodynamic applications. This technology has been in the research and development phase for over sixty years primarily for fixed wing aircraft where the early models were referred to as “blown flaps”. Circulation control works by increasing the near surface velocity of the airflow over the leading edge and/or trailing edge of a lifting surface This phenomenon keeps the boundary layer jet attached to the wing surface thus increasing the lift generated on the surface. The circulation control airflow adds energy to the lift force through conventional airfoil lift production and by altering the circulation of stream lines around the airfoil. For this study, a 10:1 aspect ratio elliptical airfoil with a chord length of 11.8 inches and a span of 31.5 inches was inserted into the West Virginia University Closed Loop Wind Tunnel and was tested at varying wind speeds (80, 100, and 120 feet per second), angle of attack (zero to sixteen degrees), and blowing coefficients, ranging from 0.0006 to 0.0127 depending on plenum pressure. By comparing the non-circulation controlled wing with the active circulation control data, a trend was found as to the influence of circulation control on the stall characteristics of the wing for trailing edge active control. For this specific case, when the circulation control is in use on the 10:1 elliptical airfoil, the stall angle decreased, from eight degrees to six degrees, while providing a 70% increase in lift coefficient. It should be noted that due to the trailing edge location of the circulation control exit jet, a “virtual” camber is created with the free stream air adding length to the overall airfoil. Due to this phenomena, the actual stall angle measured increased from eight degrees on the un-augmented airfoil, to a maximum of twelve degrees.

Effects of leading-edge bevel angle on the aerodynamic forces of a non-slender 50° delta wing

2005 ◽  
Vol 109 (1098) ◽  
pp. 403-407 ◽  
Author(s):  
J. J. Wang ◽  
S. F. Lu
Keyword(s):  
Delta Wing ◽  
Lift Coefficient ◽  
Leading Edge ◽  
Relative Thickness ◽  
Aerodynamic Performances ◽  
Stall Angle ◽  
Drag Ratio ◽  
Low Speed Wind Tunnel ◽  
Lift To Drag Ratio ◽  
Blunt Leading Edge

Abstract The aerodynamic performances of a non-slender 50° delta wing with various leading-edge bevels were measured in a low speed wind tunnel. It is found that the delta wing with leading-edge bevelled leeward can improve the maximum lift coefficient and maximum lift to drag ratio, and the stall angle of the wing is also delayed. In comparison with the blunt leading-edge wing, the increment of maximum lift to drag ratio is 200%, 98% and 100% for the wings with relative thickness t/c = 2%, t/c = 6.7% and t/c = 10%, respectively.

scholarly journals Design and Validation of a New Morphing Camber System by Testing in the Price—Païdoussis Subsonic Wind Tunnel

Aerospace ◽  
2020 ◽  
Vol 7 (3) ◽  
pp. 23 ◽  
Author(s):  
David Communier ◽  
Ruxandra Mihaela Botez ◽  
Tony Wong
Keyword(s):  
Wind Tunnel ◽  
Unmanned Aerial Vehicle ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Leading Edge ◽  
Trailing Edge ◽  
Subsonic Wind Tunnel ◽  
Aerial Vehicle ◽  
Stall Angle

This paper presents the design and wind tunnel testing of a morphing camber system and an estimation of performances on an unmanned aerial vehicle. The morphing camber system is a combination of two subsystems: the morphing trailing edge and the morphing leading edge. Results of the present study show that the aerodynamics effects of the two subsystems are combined, without interfering with each other on the wing. The morphing camber system acts only on the lift coefficient at a 0° angle of attack when morphing the trailing edge, and only on the stall angle when morphing the leading edge. The behavior of the aerodynamics performances from the MTE and the MLE should allow individual control of the morphing camber trailing and leading edges. The estimation of the performances of the morphing camber on an unmanned aerial vehicle indicates that the morphing of the camber allows a drag reduction. This result is due to the smaller angle of attack needed for an unmanned aerial vehicle equipped with the morphing camber system than an unmanned aerial vehicle equipped with classical aileron. In the case study, the morphing camber system was found to allow a reduction of the drag when the lift coefficient was higher than 0.48.

scholarly journals Improvement of Aerodynamic Performance of Cambered Airfoils Using Leading-Edge Slots

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Saman Beyhaghi ◽  
Ryoichi S. Amano
Keyword(s):  
Lift Coefficient ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Bottom Surface ◽  
Original Design ◽  
Local Pressure ◽  
Maximum Increase ◽  
Average Improvement ◽  
Length Width ◽  
Inlet Angle

Feasibility of increasing lift and decreasing drag by drilling narrow span-wide channels near the leading edge of NACA 4412 airfoils is investigated. It is proposed to drill two-segment slots that allow some of the incoming air to flow through them and then exit from the bottom surface of the airfoil. Such slots can result in an increased local pressure and thereby higher lift. Length, width, inlet angle, and exit angle of slots are varied to determine optimum configurations. Aerodynamic performance at different angles of attack (AoAs) and the chord-based Reynolds number of 1.6 × 106 is investigated. It is concluded that longer and narrower slots with exit streams more aligned with the air flowing below the airfoil can result in a higher lift. Also, in order to keep the slotted airfoils beneficial for AoAs greater than zero, it is proposed to (a) slightly lower the slot position with respect to the original design and (b) tilt up the first-leg by a few degrees. For the best design case considered, an average improvement of 8% is observed for lift coefficient over the entire range of AoA (with the maximum increase of 15% for AoA = 0), without any significant drag penalty.

Lift Augmentation between Passive and Active Vortex Generator

2016 ◽  
Vol 851 ◽  
pp. 532-537
Author(s):  
Nur Faraihan Zulkefli ◽  
Zulhilmy Sahwee ◽  
Nurhayati Mohd Nur ◽  
Muhamad Nor Ashraf Mohd Fazil ◽  
Muaz Mohd Shukri
Keyword(s):  
Reynolds Number ◽  
Lift Coefficient ◽  
Vortex Generator ◽  
Leading Edge ◽  
Plasma Actuator ◽  
Triangular Shape ◽  
Subsonic Wind Tunnel ◽  
Different Types ◽  
Drag Ratio ◽  
Lift To Drag Ratio

This study was conducted to investigate the performance of passive and active vortex generator on the wing’s flap. The triangular shape of passive vortex generator (VG) was developed and attached on the wing’s flap leading edge while the plasma actuator performed as active vortex generator. The test was carried out experimentally using subsonic wind tunnel with 300 angles extended flap. Three different types of turbulent flow; with Reynolds number 1.5 x105, 2.0 x105, and 2.6x105 were used to study the aerodynamics forces of airfoil with plasma actuator OFF. All Reynolds number used were below 1x106. The result indicated that airfoil with plasma actuator produced higher lift coefficient 12% and lift-to-drag ratio 5% compared to airfoil with passive vortex generator. The overall result showed that airfoil with plasma actuator produced better lift forces compared to passive vortex generator.

Two-dimensional impervious sails: experimental results compared with theory

1984 ◽  
Vol 144 ◽  
pp. 445-462 ◽  
Author(s):  
B. G. Newman ◽  
H. T. Low
Keyword(s):  
Reynolds Number ◽  
Dynamic Instability ◽  
Two Dimensional ◽  
Poor Agreement ◽  
Trailing Edge ◽  
Small Incidence ◽  
Visualization Experiments ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Edge Flow

Experiments have been made on quasi two-dimensional sails of small camber and at small incidence. Four excess-length ratios have been tested at a Reynolds number of 1.2 x 105. The results for lift, tension, centre of lift, maximum camber and its position, and leading- and trailing-edge membrane angles have been compared with existing inviscid theories and show poor agreement in general. This is attributed to leading- and trailing-edge flow separations as indicated by supplementary flow-visualization experiments. The optimum incidences in particular are much greater than the theoretical value of 0°. Luffing occurs at slightly negative incidences and appears to be a dynamic instability. The highest lift-to-drag ratio obtained was 16.5 on a membrane with an excess-length ratio of 0.03.

Some Simple Results for Two-Dimensional Jet-Flap Aerofoils

1958 ◽  
Vol 9 (4) ◽  
pp. 395-406 ◽  
Author(s):  
D. A. Spence
Keyword(s):  
High Velocity ◽  
Lift Coefficient ◽  
Two Dimensional ◽  
Trailing Edge ◽  
Momentum Coefficient ◽  
Image Position ◽  
Derivatives Of

SummaryIt is shown from elementary considerations that the lift coefficient of a thin two-dimensional wing at zero incidence, with a narrow high-velocity jet of momentum coefficient Cj issuing from its trailing edge at a (small) downward inclination τ, is given byand the loading on the chord line (0<x<1) by(except in a certain neighbourhood of the trailing edge), for small values of Cj. These formulae agree well with known measurements. Interpolation formulae for derivatives of CL at larger values of CJ based on earlier work, are also given:

Numerical Investigation of Bionic Rudder With Leading-Edge Protuberances

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Hongtao Gao ◽  
Wencai Zhu
Keyword(s):  
Electron Microscopy ◽  
Lift Coefficient ◽  
Leading Edge ◽  
Hydrodynamic Performance ◽  
Spanwise Direction ◽  
Flow Mechanism ◽  
Suction Surface ◽  
Edge Profile ◽  
Drag Ratio ◽  
Lift To Drag Ratio

The duck's webbed feet are observed by using electron microscopy, and observations indicate that the edges of the webbed feet are the shape of protuberances. Therefore, the rudder with leading-edge protuberances is numerically studied in the present investigation. The rudder has a sinusoidal leading-edge profile along the spanwise direction. The hydrodynamic performance of rudder is analyzed under the influence of leading-edge protuberances. The present investigations are carried out at Re = 3.2 × 105 and 8 × 105. In the case of Re = 3.2 × 105, the curves of lift coefficient illustrate that the protuberant leading-edge scarcely affects the lift coefficient of bionic rudder. However, the drag coefficient of the bionic rudder is markedly lower than that of the unmodified rudder. Therefore, the lift-to-drag ratio of the bionic rudder is obviously higher than the unmodified rudder. In another case of Re = 8 × 105, the advantageous behavior of the bionic rudder with leading-edge protuberances is mainly performed in the post-stall regime. The flow mechanism of the significantly increased efficiency by the protuberant leading-edge is explored. It is obvious that the pairs of counter-rotating vortices are presented over the suction surface of bionic rudder, and therefore, the flow is more likely to adhere to the suction surface of bionic rudder.

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