scholarly journals Evaluation of Dynamic Characteristics for a Submerged Body with Large Angle of Attack Motion via CFD Analysis

2021 ◽  
Author(s):  
Myungjun Jeon ◽  
Thi Loan Mai ◽  
Hyeon Kyu Yoon ◽  
Jaekwan Ryu ◽  
Wonhee Lee ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Angle Of Attack ◽  
Large Angle ◽  
Cfd Analysis ◽  
Submerged Body

scholarly journals Comparative Study of Different Turbulence Models for Cavitational Flows around NACA0012 Hydrofoil

2021 ◽  
Vol 9 (7) ◽  
pp. 742
Author(s):  
Minsheng Zhao ◽  
Decheng Wan ◽  
Yangyang Gao
Keyword(s):  
Angle Of Attack ◽  
Large Angle ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Specific Information ◽  
Cloud Cavitation ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Shedding Frequency ◽  
Reynolds Average

The present work focuses on the comparison of the numerical simulation of sheet/cloud cavitation with the Reynolds Average Navier-Stokes and Large Eddy Simulation(RANS and LES) methods around NACA0012 hydrofoil in water flow. Three kinds of turbulence models—SST k-ω, modified SST k-ω, and Smagorinsky’s model—were used in this paper. The unstable sheet cavity and periodic shedding of the sheet/cloud cavitation were predicted, and the simulation results, namelycavitation shape, shedding frequency, and the lift and the drag coefficients of those three turbulence models, were analyzed and compared with each other. The numerical results above were basically in accordance with experimental ones. It was found that the modified SST k-ω and Smagorinsky turbulence models performed better in the aspects of cavitation shape, shedding frequency, and capturing the unsteady cavitation vortex cluster in the developing and shedding period of the cavitation at the cavitation number σ = 0.8. At a small angle of attack, the modified SST k-ω model was more accurate and practical than the other two models. However, at a large angle of attack, the Smagorinsky model of the LES method was able to give specific information in the cavitation flow field, which RANS method could not give. Further study showed that the vortex structure of the wing is the main cause of cavitation shedding.

FEM/CFD analysis of wings at different angle of attack

2020 ◽  
Vol 26 ◽  
pp. 1638-1643 ◽  
Author(s):  
Arnav Kulshreshtha ◽  
Sanjeev Kumar Gupta ◽  
Piyush Singhal
Keyword(s):  
Angle Of Attack ◽  
Cfd Analysis

scholarly journals Experimental Study of Sand Particle Deposition on a Film-Cooled Turbine Blade at Different Gas Temperatures and Angles of Attack

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 811 ◽  
Author(s):  
Fei Zhang ◽  
Zhenxia Liu ◽  
Zhengang Liu ◽  
Weinan Diao
Keyword(s):  
Turbine Blade ◽  
Film Cooling ◽  
Particle Deposition ◽  
Angle Of Attack ◽  
Large Angle ◽  
Capture Efficiency ◽  
Gas Temperature ◽  
Trailing Edge ◽  
Pressure Surface ◽  
Film Cooling Holes

Particle deposition tests were conducted in a turbine deposition facility with an internally staged single-tube combustor to investigate the individual effect of the gas temperature and angle of attack. Sand particles were seeded to the combustor and deposited on a turbine blade with film-cooling holes at temperatures representative of modern engines. Fuel-air ratios were varied from 0.022 to 0.037 to achieve a gas temperature between 1272 and 1668 K. Results show that capture efficiency increased with increasing gas temperature. A dramatic increase in capture efficiency was noted when gas temperature exceeded the threshold. The deposition formed mostly downstream of the film-cooling holes on the pressure surface, while it concentrated on the suction surface at the trailing edge. Deposition tests at angles of attack between 10° and 40° presented changes in both deposition mass and distribution. The capture efficiency increased with the increase in the angle of attack, and simultaneously the growth rate slowed down. On the blade pressure surface, sand deposition was distributed mainly downstream of the film-cooling holes near the trailing edge in the case of the small angle of attack, while it concentrated on the region around the film-cooling holes near the leading edge, resulting in the partial blockage of holes, in the case of the large angle of attack.

Unsteady Study on the Effects of Matching Characteristic of Tandem Cascade on the Performance and Flow at Large Angle of Attack

2018 ◽  
Vol 27 (6) ◽  
pp. 505-515 ◽  
Author(s):  
Hanru Liu ◽  
Shaoyuan Yue ◽  
Yangang Wang ◽  
Jun Zhang
Keyword(s):  
Angle Of Attack ◽  
Large Angle

Experiments on the Weis-Fogh mechanism of lift generation by insects in hovering flight. Part 1. Dynamics of the ‘fling’

1979 ◽  
Vol 93 (1) ◽  
pp. 47-63 ◽  
Author(s):  
T. Maxworthy
Keyword(s):  
Initial Phase ◽  
Angle Of Attack ◽  
Large Angle ◽  
Leading Edge ◽  
Tip Vortex ◽  
Hovering Flight ◽  
Separation Bubbles ◽  
Mechanical Models ◽  
Series Of Experiments ◽  
Edge Separation

From a series of experiments using simplified mechanical models we suggest certain minor modifications to the Weis-Fogh (1973)–Lighthill (1973) explanation of the so-called ‘clap and fling’ mechanism for the generation of large lift coefficients by insects in hovering flight. Of particular importance is the production and motion of a leading edge, separation vortex that accounts for virtually all of the circulation generated during the initial phase of the ‘fling’ process. The magnitude of this circulation is substantially larger than that calculated using inviscid theory. During the motion that subsequently separates the wings, the vorticity over each of them is convected and combined to become a tip vortex of uniform circulation spanning the space between them. This combined vortex moves downwards as a part of a ring, of large impulse, that is then continuously fed from quasi-steady separation bubbles that move with the wings as they continue to open at a large angle of attack. Such effects are able to account for the large lift forces generated by the insect.

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