Aerodynamic Characteristics of an Airborne Vertical Gradient Magnetic Measuring Probe on the Wing Tip of a High Aspect Ratio UAV with Low Speed

2020 ◽  
Author(s):  
S. B. Jia ◽  
S. J. Luo ◽  
Y. Wang ◽  
Y. L. Cui ◽  
S. J. Guo ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Vertical Gradient ◽  
Aerodynamic Characteristics ◽  
Low Speed ◽  
Measuring Probe ◽  
Magnetic Measuring ◽  
Wing Tip

Influence of Circumferential Inflow Distortion on the Performance of a Low Speed, High Aspect Ratio Contra Rotating Axial Fan

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Chetan Mistry ◽  
A. M. Pradeep
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Rotational Speed ◽  
Total Pressure ◽  
Flow Behavior ◽  
Axial Fan ◽  
Low Speed ◽  
Overall Performance ◽  
Design Speed ◽  
Inflow Conditions

The influence of circumferential inflow distorted on the performance and flow behavior of a high aspect ratio, low speed contra rotating fan is reported in this paper. The total pressure at the inlet is artificially distorted by means of 90 deg mesh sector with a porosity of 0.70. The performance of the contra rotating fan was studied under different speed combinations of the two rotors under clean and distorted inflow conditions. Detailed flow analyses were conducted under design and off-design conditions. In order to understand the effect of distortion and its extent, the distortion sector was rotated circumferentially at intervals of 15 deg to cover the entire annulus. Detailed measurements of the total pressure, velocity components, and flow angles were carried out at the inlet of the first rotor, between the two rotors, and at the exit of the second rotor. The study reveals a few interesting aspects on the effect of inflow distortion on the performance of a contra-rotating stage. For the design speed combination and lower rotational speed of rotor-2, a reduction in the overall operating range with a shift of the peak pressure point towards higher mass flow rate, was observed. It is observed that the effect of inflow distortion at the inlet of rotor-1 gets transferred in the direction of rotor-1 rotation and spreads across the entire annulus. The opposite sense of rotation of rotor-2 causes the distortion effect to get transferred in the direction of rotation of rotor-2 with an associated reduction in the total pressure near the hub. It is observed that a higher rotational speed of the second rotor has a beneficial effect on the overall performance due to the strong suction by generated higher rotational speed of rotor-2.

Correction: Testing of Folding Wing-Tip for Gust Load Alleviation in High Aspect Ratio Wing

2019 ◽  
Author(s):  
Ronald C. Cheung ◽  
Djamel Rezgui ◽  
Jonathan E. Cooper ◽  
Thomas Wilson
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Folding Wing ◽  
Gust Load Alleviation ◽  
Wing Tip

An experimental parametric study on planar sheared wings tip devices for low-to-moderate aspect ratio wings

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Lourelay Moreira dos Santos ◽  
Guilherme Ferreira Gomes ◽  
Rogerio F. Coimbra
Keyword(s):  
Wind Tunnel ◽  
Aspect Ratio ◽  
Parametric Study ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Sweep Angle ◽  
Wind Tunnel Tests ◽  
Content Type ◽  
Wing Tips ◽  
Wing Tip

Purpose The purpose of this study is to investigate the aerodynamic characteristics of a low-to-moderate-aspect-ratio, tapered, untwisted, unswept wing, equipped of sheared wing tips. Design/methodology/approach In this work, wind tunnel tests were made to study the influence in aerodynamic characteristics over a typical low-to-moderate-aspect-ratio wing of a general aviation aircraft, equipped with sheared – swept and tapered planar – wing tips. An experimental parametric study of different wing tips was tested. Variations in its leading and trailing edge sweep angle as well as variations in wing tip taper ratio were considered. Sheared wing tips modify the flow pattern in the outboard region of the wing producing a vortex flow at the wing tip leading edge, enhancing lift at high angles of attack. Findings The induced drag is responsible for nearly 50% of aircraft total drag and can be reduced through modifications to the wing tip. Some wing tip models present complex geometries and many of them present benefits in particular flight conditions. Results have demonstrated that sweeping the wing tip leading edge between 60 and 65 degrees offers an increment in wing aerodynamic efficiency, especially at high lift conditions. However, results have demonstrated that moderate wing tip taper ratio (0.50) has better aerodynamic benefits than highly tapered wing tips (from 0.25 to 0.15), even with little less wing tip leading edge sweep angle (from 57 to 62 degrees). The moderate wing tip taper ratio (0.50) offers more wing area and wing span than the wings with highly tapered wing tips, for the same aspect ratio wing. Originality/value Although many studies have been reported on the aerodynamics of wing tips, most of them presented complex non-planar geometries and were developed for cruise flight in high subsonic regime (low lift coefficient). In this work, an exploration and parametric study through wind tunnel tests were made, to evaluate the influence in aerodynamic characteristics of a low-to-moderate-aspect-ratio, tapered, untwisted, unswept wing, equipped of sheared wing tips (wing tips highly swept and tapered).

The aeroelastic characteristics of high aspect ratio wing

2016 ◽  
Vol 230 (14) ◽  
pp. 2543-2556
Author(s):  
Fan Yang ◽  
Zhufeng Yue ◽  
Lei Li
Keyword(s):  
Aspect Ratio ◽  
Large Deformation ◽  
High Aspect Ratio ◽  
Data Exchange ◽  
Stokes Equations ◽  
Great Influence ◽  
Aerodynamic Characteristics ◽  
Interface Problem ◽  
Numerical Result ◽  
Computational Structural Mechanics

Owing to the elasticity, the large deformation was brought in the high aspect ratio wing in the flight. The large deformation had a great influence on the flight performance. In this paper, the loosely coupled method was used for the research of high aspect ratio wing aeroelastic problems. The Navier–Stokes equations were solved for fluid domain computation, and the nonlinear finite element method was adopted for solid domain computation. The data exchange program and mesh regeneration progress were adopted for fluid–structure interface problem. Finally, the aerodynamic characteristics of high aspect ratio wing were obtained under different fly conditions. In addition, to validate the proposed method, the flutter analysis of AGARD 445.6 wing is carried out and compared with the experimental data. The numerical result validates the proposed computational fluid dynamics/computational structural mechanics method.

Effect of Speed Ratio and Axial Spacing Variations on the Performance of a High Aspect Ratio, Low Speed Contra-Rotating Fan

2012 ◽  
Author(s):  
Chetan S. Mistry ◽  
A. M. Pradeep
Keyword(s):  
Aspect Ratio ◽  
Numerical Simulations ◽  
High Aspect Ratio ◽  
Total Pressure ◽  
Experimental Studies ◽  
Pressure Rise ◽  
Operating Conditions ◽  
Speed Ratio ◽  
Stall Margin ◽  
Low Speed

This paper explores the effect of speed ratio and axial spacing between high aspect ratio, low speed contra-rotating pair rotors on their aerodynamic performance. The blades were designed with a low hub-tip ratio of 0.35 and an aspect ratio of 3.0. Numerical and experimental studies are carried out on these contra-rotating rotors operating at a Reynolds number of 1.258 × 105 (based on blade chord). The first and second rotors were designed to develop a pressure rise of 1100 Pa and 900 Pa, respectively, for total mass flow rate of 6 kg/s when both operating at a design speed of 2400 rpm. The performance of the fan was evaluated based on variations of total pressure and flow angles at off-design operating conditions. The measurementsof total pressure rise, flow angles etc. are taken upstream of the first rotor and in between the two rotors and downstream of the second rotor. The performance of the contra rotating stage is mainly influenced by the axial spacing between the rotors and speed ratio of both the rotors. The study reveals that the aerodynamics of the contra-rotating stage and stall margin is significantly affected by both the speed ratio as well as the axial spacing between the rotors. It was found that with increasing the speed ratio, the strong suction generated by the second rotor, improves the stage pressure rise and stall margin. Lower axial spacing changes the flow incidence to the second rotor and thereby improves the overall performance of the stage. This however, is accompanied by an increased noise level. The performance is investigated at different speed ratios of the rotors at varying axial spacing. Detailed numerical simulations have been conducted using ANSYS CFX13© using mixing plane approach between rotors. Numerical simulations are compared with experimental results at off-design conditions. These results are validated using the experimental data. Numerical simulations are expected to provide deeper insight into the flow physics of contra-rotating rotors which may be difficult to capture experimentally.

Static Aeroelasticity Analysis of High Aspect Ratio Wing and the Jig-Shape Design Based on Multi-Block Structural Grid

2013 ◽  
Vol 302 ◽  
pp. 377-383 ◽  
Author(s):  
Yan Liu ◽  
Jun Qiang Bai ◽  
Jun Hua
Keyword(s):  
Aspect Ratio ◽  
Design Process ◽  
High Aspect Ratio ◽  
Design Method ◽  
Aerodynamic Characteristics ◽  
Shape Design ◽  
Transport Aircraft ◽  
Mesh Motion ◽  
Static Aeroelasticity ◽  
Motion Method

The influence of structural elastic deformation on the aerodynamic characterisitcs of large transport aircraft has been researched. A method of static aeroelasticity based on multi-block structural grid of high aspect ratio wing has been established, and then a design method of jig-shape is developed. The technology of RBF interpolation is used to exchange the data of CFD/CSD. Based on RBF&Delaunay technology, a mesh motion method is developed to make the design process less time-consuming, which can be applied to large deformation of multi-block structural grid. The static aeroelastic deformation of a wing-body of large transport aircraft is analyzed. Then the wing-body's jig-shape is designed. Compared the aerodynamic characteristics between design cruise shape and target cruise shape, it shows that the aerodynamic characteristics of design cruise shape is almost equal to target cruise shape and the design process of jig-shape is feasible.

Investigations on the Effect of Inflow Distortion on the Performance of a High Aspect Ratio, Low Speed Contra Rotating Fan Stage

2013 ◽  
Author(s):  
Chetan S. Mistry ◽  
A. M. Pradeep
Keyword(s):  
Experimental Study ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Total Pressure ◽  
Flow Behavior ◽  
Variable Speed ◽  
Low Speed ◽  
Inlet Distortion ◽  
Overall Performance ◽  
Inflow Conditions

In this paper, results from an experimental study on the effect of circumferential inflow distorted on the performance and flow behavior of a high aspect ratio, low speed contra rotating fan, are reported. The total pressure at the inlet is artificially distorted by means of 90° mesh sector having porosity of 0.70. The performance of contra rotating fan was studied under variable speed combinations of rotors under clean and distorted inflow conditions. Detailed flow analyses were conducted under design and off-design conditions. In order to understand the extent of inlet distortion, the distortion sector was rotated circumferentially at intervals of 15° to cover the entire annulus. Detailed measurements of total pressure, velocity components and flow angles were carried out at the inlet of the first rotor, between the two rotors and at the exit of the second rotor. The study reveals a few interesting aspects on the effect of inflow distortion on the performance of a contra-rotating stage. It is observed that a higher rotational speed of the second rotor has a beneficial effect on the overall performance.

scholarly journals Testing of Folding Wing-Tip for Gust Load Alleviation in High Aspect Ratio Wing

2019 ◽  
Author(s):  
Ronald C. Cheung ◽  
Djamel Rezgui ◽  
Jonathan E. Cooper ◽  
Thomas Wilson
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Folding Wing ◽  
Gust Load Alleviation ◽  
Wing Tip
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