Aeroacoustics of a High-Speed Train Double Model at High Reynolds Numbers

2012 ◽  
Author(s):  
A. Lauterbach ◽  
K. Ehrenfried ◽  
S. Loose ◽  
C. Wagner
Keyword(s):  
High Speed ◽  
Reynolds Numbers ◽  
High Speed Train ◽  
High Reynolds Numbers ◽  
High Reynolds

Vortex Induced Vibration Tests of Smooth and Rough Flexible Cylinders at High Reynolds Numbers

2005 ◽  
Author(s):  
Don W. Allen ◽  
Dean L. Henning ◽  
Li Lee
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
Single Mode ◽  
Reynolds Numbers ◽  
Circular Path ◽  
Exterior Surface ◽  
Vortex Induced Vibration ◽  
High Reynolds Numbers ◽  
Sheared Flows ◽  
High Reynolds

Vortex-induced vibration (VIV) tests have been performed on long, flexible pipes with various levels of roughness, in sheared flows in a circular towing tank at high Reynolds numbers. The test pipes, made of fiberglass composite, were mounted horizontally beneath a rotating arm that has a span of 129 ft, and a width of 25 ft. As the towing bridge rotates, it drives the cylinder in a circular path in still water. The sheared flows experienced by the cylinder excite its VIV motion. The Reynolds numbers for the tests reported herein ranged from 152,000 to 339,000 at the high-speed end of the pipe. Two surface roughness levels were tested: one comprised of the exterior surface of a filament wound fiberglass pipe; and one with carpet glued to the exterior of the pipe. The VIV responses of the test cylinders, represented by displacement time traces, spectrum, and motion trajectories, are presented in this paper. Effects of the surface roughness and Reynolds numbers on the VIV responses are discussed. The response behavior of the cylinders varied from single-mode dominance to multi-mode responses, in addition to certain traveling wave activities. These results should be of interest to researchers and engineers in the area of vortex-induced vibrations.

TRANSONIC CROSS FLOW (M∞ = 0.8) OVER A CIRCULAR CYLINDER AT HIGH REYNOLDS NUMBERS

2012 ◽  
Vol 43 (5) ◽  
pp. 589-613
Author(s):  
Vyacheslav Antonovich Bashkin ◽  
Ivan Vladimirovich Egorov ◽  
Ivan Valeryevich Ezhov ◽  
Sergey Vladimirovich Utyuzhnikov
Keyword(s):  
Circular Cylinder ◽  
Cross Flow ◽  
Reynolds Numbers ◽  
High Reynolds Numbers ◽  
High Reynolds

Oscillatory control of separation at high Reynolds numbers

AIAA Journal ◽  
1999 ◽  
Vol 37 ◽  
pp. 1062-1071 ◽  
Author(s):  
A. Seifert ◽  
L. G. Pack
Keyword(s):  
Reynolds Numbers ◽  
High Reynolds Numbers ◽  
High Reynolds

Turbulent vortex breakdown at high Reynolds numbers

AIAA Journal ◽  
2000 ◽  
Vol 38 ◽  
pp. 825-834
Author(s):  
F. Novak ◽  
T. Sarpkaya
Keyword(s):  
Vortex Breakdown ◽  
Reynolds Numbers ◽  
Turbulent Vortex ◽  
High Reynolds Numbers ◽  
High Reynolds

Drag Measurements on Long Thin Cylinders at Small Angles and High Reynolds Numbers

2004 ◽  
Author(s):  
William L. Keith ◽  
Kimberly M. Cipolla ◽  
David R. Hart ◽  
Deborah A. Furey
Keyword(s):  
Reynolds Numbers ◽  
High Reynolds Numbers ◽  
High Reynolds

An Experimental and Numerical Study of Heat Transfer and Pressure Loss in a Rectangular Channel With V-Shaped Ribs

2006 ◽  
Author(s):  
Michael Maurer ◽  
Jens von Wolfersdorf ◽  
Michael Gritsch
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Thermal Performance ◽  
Pressure Loss ◽  
Numerical Study ◽  
Rectangular Channel ◽  
Reynolds Numbers ◽  
Transfer Enhancement ◽  
High Reynolds Numbers ◽  
High Reynolds

An experimental and numerical study was conducted to determine the thermal performance of V-shaped ribs in a rectangular channel with an aspect ratio of 2:1. Local heat transfer coefficients were measured using the steady state thermochromic liquid crystal technique. Periodic pressure losses were obtained with pressure taps along the smooth channel sidewall. Reynolds numbers from 95,000 to 500,000 were investigated with V-shaped ribs located on one side or on both sides of the test channel. The rib height-to-hydraulic diameter ratios (e/Dh) were 0.0625 and 0.02, and the rib pitch-to-height ratio (P/e) was 10. In addition, all test cases were investigated numerically. The commercial software FLUENT™ was used with a two-layer k-ε turbulence model. Numerically and experimentally obtained data were compared. It was determined that the heat transfer enhancement based on the heat transfer of a smooth wall levels off for Reynolds numbers over 200,000. The introduction of a second ribbed sidewall slightly increased the heat transfer enhancement whereas the pressure penalty was approximately doubled. Diminishing the rib height at high Reynolds numbers had the disadvantage of a slightly decreased heat transfer enhancement, but benefits in a significantly reduced pressure loss. At high Reynolds numbers small-scale ribs in a one-sided ribbed channel were shown to have the best thermal performance.

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