Pitching effect on transonic wing stall of a blended flying wing with low aspect ratio

Numerical simulation of the pitching effect on transonic wing stall of a blended flying wing with low aspect ratio was performed using improved delayed detached eddy simulation (IDDES). To capture the discontinuity caused by shock wave, a second-order upwind scheme with Roe’s flux-difference splitting is introduced into the inviscid flux. The artificial dissipation is also turned off in the region where the upwind scheme is applied. To reveal the pitching effect, the implicit approximate-factorization method with sub-iterations and second-order temporal accuracy is employed to avoid the time integration of the unsteady Navier–Stokes equations solved by finite volume method at Arbitrary Lagrange–Euler (ALE) form. The leading edge vortex (LEV) development and LEV circulation of pitch-up wings at a free-stream Mach number M = 0.9 and a Reynolds number Re = [Formula: see text] is studied. The Q-criterion is used to capture the LEV structure from shear layer. The result shows that a shock wave/vortex interaction is responsible for the vortex breakdown which eventually causes the wing stall. The balance of the vortex strength and axial flow, and the shock strength, is examined to provide an explanation of the sensitivity of the breakdown location. Pitching motion has great influence on shock wave and shock wave/vortex interactions, which can significantly affect the vortex breakdown behavior and wing stall onset of low aspect ratio blended flying wing.

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Tip Flow Fields in a Low Aspect Ratio Transonic Compressor

Volume 1: Turbomachinery ◽

10.1115/95-gt-089 ◽

1995 ◽

Cited By ~ 2

Author(s):

P. Russler ◽

D. Rabe ◽

B. Cybyk ◽

C. Hah

Keyword(s):

Shock Wave ◽

Aspect Ratio ◽

Flow Field ◽

High Frequency ◽

High Performance ◽

Flow Structures ◽

Transonic Compressor ◽

Low Aspect Ratio ◽

Laser Data ◽

Blade Tip

Experimental data and computational predictions are used to characterize the tip flow field of a high performance, low aspect ratio, transonic compressor. Flow structures near the first stage blade tip are monitored experimentally using two different data acquisition schemes. High frequency pressure and laser fringe anemometry data are used to experimentally define the tip flow structure. The high frequency pressure data were acquired with an array of pressure transducers mounted in the rotor casing. Laser data were acquired through a window in the same position. The transducer and laser data adequately define the shock structure at the tip. Both the movement of the shock wave in the blade passage during changes in compressor loading and the interaction between the shock wave and the tip leakage vortex are detected. Similar flow structures and compressor loading effects are numerically predicted using a three-dimensional Navier-Stokes algorithm. A fundamental understanding of the flow field at the blade tip is obtained using these three complementary methods.

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Investigation of an Expansion Fan/Shock Wave Interaction Between Low Aspect Ratio Wedges

30th International Symposium on Shock Waves 1 ◽

10.1007/978-3-319-46213-4_99 ◽

2017 ◽

pp. 581-585

Author(s):

L. Nel ◽

B. W. Skews

Keyword(s):

Shock Wave ◽

Aspect Ratio ◽

Wave Interaction ◽

Shock Wave Interaction ◽

Low Aspect Ratio ◽

Expansion Fan

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Characterization of flow oblique to a circular cylinder with low aspect ratio using 3-D detached eddy simulation

Journal of Wind Engineering and Industrial Aerodynamics ◽

10.1016/j.jweia.2011.08.002 ◽

2011 ◽

Vol 99 (11) ◽

pp. 1117-1125 ◽

Cited By ~ 10

Author(s):

DongHun Yeo ◽

Nicholas P. Jones

Keyword(s):

Aspect Ratio ◽

Circular Cylinder ◽

Detached Eddy Simulation ◽

Low Aspect Ratio ◽

Eddy Simulation

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The aeroelastic characteristics of high aspect ratio wing

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410016629497 ◽

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.

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Effects of micro-vortex generators on shock wave structure in a low aspect ratio duct, numerical investigation

Acta Astronautica ◽

10.1016/j.actaastro.2020.08.012 ◽

2021 ◽

Vol 178 ◽

pp. 616-624

Author(s):

Hadi Bagheri ◽

Seyed Ali Agha Mirjalily ◽

Seyed Amir Abbas Oloomi ◽

Mohammad Reza Salimpour

Keyword(s):

Shock Wave ◽

Aspect Ratio ◽

Numerical Investigation ◽

Wave Structure ◽

Vortex Generators ◽

Shock Wave Structure ◽

Low Aspect Ratio

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Second‐order toroidicity‐induced Alfvén eigenmodes and mode splitting in a low‐aspect‐ratio tokamak

Physics of Fluids B Plasma Physics ◽

10.1063/1.860352 ◽

1992 ◽

Vol 4 (10) ◽

pp. 3451-3453 ◽

Cited By ~ 6

Author(s):

A. D. Turnbull ◽

M. S. Chu ◽

M. S. Chance ◽

J. M. Greene ◽

L. L. Lao ◽

...

Keyword(s):

Aspect Ratio ◽

Second Order ◽

Low Aspect Ratio ◽

Mode Splitting ◽

Alfven Eigenmodes

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Research on Computational Method of Supersonic Inlet/Isolator Internal Flow

Applied Sciences ◽

10.3390/app11199272 ◽

2021 ◽

Vol 11 (19) ◽

pp. 9272

Author(s):

Zhuoran Liu ◽

Caizheng Wang ◽

Ke Zhang ◽

Zhuo Zhao ◽

Zhifeng Xie

Keyword(s):

Shock Wave ◽

Stokes Equations ◽

Transport Model ◽

Flow Simulation ◽

Side Wall ◽

Internal Flow ◽

Computational Method ◽

Detached Eddy Simulation ◽

Eddy Simulation ◽

Supersonic Inlet

In this research, a CFD solver is developed for solving the 2D/3D compressible flow problem: the finite volume method based on multi-block structural grids is used to solve the compressible Reynolds averaged Navier–Stokes equations (RANS). Included in the methodology are multiple high-order reconstruction schemes, such as the 3rd-order MUSCL (Monotone Upstreamcentered Schemes for Conservation Laws), 5th-order WENO (Weight Essentially Non-Oscillatory), and 5th-order MP (Monotonicity-Preserving) schemes. Of the variety of turbulence models that are embedded, this solver is mainly based on the shear stress transport model (SST), which is compatible with OpenMP/MPI parallel algorithms. This research uses the CFD solver to conduct steady-state flow simulation for a two-dimensional supersonic inlet/isolator, incorporating these high-precision reconstruction schemes to accurately capture the shock wave/expansion wave interaction and shock wave/turbulent boundary layer interaction (SWTBLI), among other effects. By comparing the 2D/3D computation results of the same inlet configuration, it is found that the 3D effects of the side wall cannot be ignored due to the existing strong lateral flow near the corner. To obtain a more refined turbulence simulation, the commercial software ANSYS Fluent 18.0 is used to carry out the detached eddy simulation (DES) and the large eddy simulation (LES) of the same supersonic inlet, so as to reveal the flow details near the separation area and boundary layers.

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Comparative Study on Properties of Polylactic Acid Nanocomposites with Cellulose and Chitin Nanofibers Extracted from Different Raw Materials

Journal of Nanomaterials ◽

10.1155/2017/7193263 ◽

2017 ◽

Vol 2017 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Jingjing Li ◽

Jian Li ◽

Dejun Feng ◽

Jingfeng Zhao ◽

Jingrong Sun ◽

...

Keyword(s):

Mechanical Properties ◽

Aspect Ratio ◽

Mechanical Strength ◽

Polylactic Acid ◽

Raw Materials ◽

Great Influence ◽

Crab Shell ◽

Sem Images ◽

Low Aspect Ratio ◽

Chitin Nanofibers

Polylactic acid (PLA) was reinforced with ultralong cellulose and chitin nanofibers extracted from four raw materials by extrusion. The mechanical, rheological, thermal, and viscoelastic performances of four nanocomposites were comparatively studied in detail. The results showed that fibrillation of poplar was much easier than that of cotton, and fibrillation of crab shell was relatively hard as compared to prawn shell. The poplar CNFs/PLA composite exhibited the best mechanical properties among four nanocomposites due to the highest aspect ratio of nanofibers, while both the cotton CNFs/PLA composite and the crab shell CHNFs/PLA composite had low mechanical strength due to the relatively low aspect ratio. FE-SEM images showed that the ultralong nanofibers were uniformly dispersed in PLA matrix for all four samples with the water preblending method. The CTE values of the nanocomposites with 40 wt% nanofibers extracted from poplar, cotton, crab shell, and prawn shell were 69.5 × 10−6 K−1, 79.6 × 10−6 K−1, 77.2 × 10−6 K−1, and 75.3 × 10−6 K−1, respectively. All the results indicated that the aspect ratio of the nanofibers has a great influence on the performance of the composites, irrespective of the composites prepared by cellulose or chitin.

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