Wind tunnel tests of aerodynamic interference effects on two iced vertical circular cylinders in a tandem arrangement

2021 ◽  
Author(s):  
Shengli Li ◽  
Ruiqing Han ◽  
Pan Guo ◽  
Xidong Wang ◽  
Yajie Chu
Keyword(s):  
Wind Tunnel ◽  
Shape Change ◽  
Aerodynamic Characteristics ◽  
Circular Cylinders ◽  
Future Research ◽  
Engineering Practice ◽  
Tandem Arrangement ◽  
Number Range ◽  
Wind Tunnel Tests ◽  
Study Results

Abstract The aerodynamic characteristics of the two iced vertical circular cylinders in a tandem arrangement, due to the shape change by icing, are complex, and lack systematical investigation. Therefore, a set of wind tunnel tests were carried out to study the aerodynamic characteristics of the leeward vertical cylinder, with ice shape, icing thickness, cylinder spacing, and icing relative position of cylinders varied in the subcritical Reynolds number range in this study. Results show that the icing thicknesses had a greater impact on the lift coefficients of D-shaped ice leeward cylinder at the same angle of attack. The aerodynamic characteristics of the iced leeward cylinder were stable when the ratio (L/D) of cylinder spacing was within the range of 4.8 to 6.2. The change of flow field should be considered in the stability analysis of two circular vertical cylinders. The drag coefficients of the iced leeward cylinder varied significantly due to the shielding effects, especially within the range of 9° attack angle and L < 6.2D. The results of this work can provide an experimental reference for future research on wind resistance of two circular cylindrical structures in engineering practice.

scholarly journals Planetary Atmosphere Wind Tunnel Tests on Aerodynamic Characteristics of a Mars Airplane Scale Model

2014 ◽  
Vol 12 (ists29) ◽  
pp. Pk_7-Pk_12 ◽  
Author(s):  
Masayuki ANYOJI ◽  
Masato OKAMOTO ◽  
Hidenori HIDAKA ◽  
Taku NONOMURA ◽  
Akira OYAMA ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Characteristics ◽  
Planetary Atmosphere ◽  
Scale Model ◽  
Wind Tunnel Tests

scholarly journals Aerodynamic study of a suspension bridge deck by CFD simulations, wind tunnel tests and full-scale observations

2021 ◽  
Vol 1201 (1) ◽  
pp. 012007
Author(s):  
I. Kusano ◽  
E. Cheynet ◽  
J. B. Jakobsen ◽  
J. Snæbjörnsson
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Suspension Bridge ◽  
Aerodynamic Characteristics ◽  
Full Scale ◽  
Navier Stokes ◽  
Cfd Simulations ◽  
Wind Tunnel Tests ◽  
Long Span Bridges ◽  
Wide Range

Abstract Assessing the aerodynamic characteristics of long-span bridges is fundamental for their design. Depending on the terrain complexity and local wind conditions, episodes of large angles of attack (AoA) of 15° may be observed. However, such large AoAs ( above 10°) are often overlooked in the design process. This paper studies the aerodynamics properties of a flow around a single-box girder for a wide range of AoAs, from –20° to 20°, using numerical simulations. The simulations are based on a 2D unsteady Reynolds-averaged Navier–Stokes (URANS) approach using the k − ω SST turbulence model with a Reynolds number of 1.6 × 105. Numerically obtained aerodynamic static coefficients were compared to wind tunnel test data. The CFD results were generally in good agreement with the wind tunnel tests, especially for small AoAs and positive AoAs. More discrepancies were observed for large negative AoA, likely due to the limitation of modelling 3D railings with 2D simulations. The simulated velocity deficit downstream of the deck was consistent with the one measured in full-scale using short-range Doppler wind lidar instruments. Finally, the Strouhal number from the CFD simulations were in agreement with the value obtained from the full-scale data.

scholarly journals Aerodynamic Characteristics of Individual Ballast Particle by Wind Tunnel Tests

2014 ◽  
Vol 7 (2) ◽  
pp. 137-142 ◽  
Author(s):  
G. Q. Jing ◽  
◽  
G. X. Liu ◽  
J. Lin ◽  
J. Martinez ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Characteristics ◽  
Wind Tunnel Tests

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).

Study on the Aerodynamic Characteristics and Galloping Instability of Conductors Covered with Sector-Shaped Ice by a Wind Tunnel Test

2020 ◽  
Vol 20 (06) ◽  
pp. 2040016
Author(s):  
Jia-Xiang Li ◽  
Jian Sun ◽  
Ye Ma ◽  
Shu-Hong Wang ◽  
Xing Fu
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Ice Thickness ◽  
Shape Parameters ◽  
Aerodynamic Coefficient ◽  
Wind Tunnel Tests ◽  
And Control

Conductors with sector-shaped ice are susceptible to galloping. To prevent and control galloping, it is necessary to study the conductor aerodynamic characteristics. Wind tunnel tests were performed to study the influence of two shape parameters (ice thickness and ice angle) of a conductor with sector-shaped ice on the aerodynamic characteristics considering the roughness of the surface. In addition, the unstable areas for galloping are discussed according to Den Hartog theory and Nigol theory. The results show that with increasing ice thickness, the aerodynamic coefficient curves fluctuate more strongly, and galloping tends to occur; with increasing ice angle, the unstable area becomes larger according to Nigol theory, and the increasing drag coefficient will suppress the unstable areas according to Den Hartog theory. With the increasing two shape parameters, the most affected ranges of the aerodynamic coefficient curves are 150–180∘.

scholarly journals Study on Transient Dynamics and Aerodynamic Characteristics of a New Type of High-Damping Four-Winged Rotating Parachute Inflation Process

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Yang Li ◽  
Chunlan Jiang ◽  
Liang Mao ◽  
Ming Li
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Characteristics ◽  
Resistance Coefficient ◽  
Fe Model ◽  
Wind Tunnel Tests ◽  
Development Cycle ◽  
Military Background ◽  
New Type ◽  
Parachute Inflation ◽  
The Cost

To decrease the opening shock as well as improve the resistance coefficient and stability of the parachute of aviation weapon under subsonic conditions, a new kind of high-damping four-winged rotating (HFWR) parachute is investigated in this paper. The transient dynamic behavior and aerodynamic characteristics of the parachute during the inflation process are studied. Considering the permeability, the 3D folded finite element (FE) model of the HFWR parachute is established based on the direct folding modeling technique, and the inflation process of the parachute under subsonic flow is simulated using the multimaterial arbitrary Lagrange–Euler (ALE) method. A series of wind tunnel tests are conducted to verify the numerical results. Besides, the opening performances of the HFWR parachute and the round parachute, which includes the inflation process, the dynamic response of the swing angle, and the opening shock load varying with time, are compared under the same conditions. The results show that the opening performance of the HFWR parachute is superior to the round parachute under specific military background. The fluid-structure interaction (FSI) simulation results show good consistency with the wind tunnel tests, which indicates that the numerical modeling can effectively simulate and predict the opening performance and aerodynamic characteristics of the rotating parachute. The modeling method in this paper can help shorten the development cycle, improve the cost effectiveness, and optimize the design of the parachute.

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