Simulating the Role of Axial Flow in Stay Cable Vibrations via a Perforated Wake Splitter Plate

2018 ◽  
Author(s):  
Ran Wang ◽  
Shaohong Cheng ◽  
David S-K. Ting
Keyword(s):  
Axial Flow ◽  
Splitter Plate ◽  
Stay Cable ◽  
Cable Vibrations

The Role of Axial Flow in Near Wake on the Cross-Flow Vibration of the Inclined Cable of Cable-Stayed Bridges

2010 ◽  
Author(s):  
Masaru Matsumoto
Keyword(s):  
Vortex Shedding ◽  
Cross Flow ◽  
Axial Flow ◽  
Splitter Plate ◽  
Near Wake ◽  
Karman Vortex ◽  
The Cross ◽  
Wind Induced Vibration ◽  
Cable Stayed Bridges

Nowadays, the violent wind-induced vibration, including “rain-wind induced vibration” and “dry-galloping”, of stay-cables of cable-stayed bridges has become the most serious issue for bridge design. Up-to-date, the major factors for excitation of inclined cables have been clarified to be, for “rain-wind” induced vibration, the formation of “water-rivulet” on the particular position of upper cable surface, and, for “dry galloping”, the “axial flow” which flows in the near wake along cable-axis, and the effect of drag-force associated with Reynolds number, separately. However, the details of the effect of “axial flow” remain unsolved. Thus, this study aims to clarify the effect of axial flow in near wake on the aero-elastic vibration of inclined cables basing on various experiments. The mean velocity of axial flow was almost 60% of approaching wind velocity. Furthermore, the aerodynamic effect of the “axial flow” on cross-flow vibration of inclined cables is discussed in relation to the mitigation of Karman vortex shedding in near wake. Since the role of axial flow seems to be similar to the splitter plate installed in wake from the point of mitigation of Karman vortex shedding, to clarify the cross-flow response in relation to the mitigation of Karman vortex, the perforated ratio of the splitter plate was variously changed, then the similarity of effect of axial flow and the one of splitter plate was verified comparing their unsteady lift force-characteristics. In summary, it is shown that the axial flow on aerodynamic cross-flow vibration might excite like galloping similarly with the splitter plate by mitigation of Karman vortex.

AXITURB: A Full Computer Implementation of the NASA Design Procedure for Axial-Flow Turbines

1993 ◽  
Author(s):  
P. C. Lu ◽  
Chen-Ying Wang
Keyword(s):  
Alkali Metals ◽  
Axial Flow ◽  
Design Procedure ◽  
Rankine Cycle ◽  
Eutectic Alloys ◽  
Singular Case ◽  
Cycle Space ◽  
Power Turbine ◽  
Parametric Studies

Abstract A recent task to design a Rankine-cycle space-power turbine system employing eutectic alloys of alkali metals prompted the present authors to re-examine the NASA design procedure for axial-flow turbines, as outlined by Glassman and Futral (and based on works of Stewart) in 1963. After clarifying the role of the singular case of a single-stage turbine, and organizing the procedure in clear steps, a computer program AXITURB was written. The present paper reports essentially the success of AXITURB in performing parametric studies of NaK and CsK turbines (using 78.4% and 23.1%, respectively, of potassium by weight), after re-generating all the reported NASA designs for turbines employing pure Na, K and Cs. An outline of design steps is also given. AXITURB has been put in public domain. Its heavily commented source code in FORTRAN is available to designers for adaption or modification.

scholarly journals Full-Scale Measurements and System Identification on Sutong Cable-Stayed Bridge during Typhoon Fung-Wong

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Hao Wang ◽  
Tianyou Tao ◽  
Tong Guo ◽  
Jian Li ◽  
Aiqun Li
Keyword(s):  
Damping Ratio ◽  
Wind Tunnel Test ◽  
Full Scale ◽  
Structural Vibration ◽  
Stay Cable ◽  
Characteristic Analysis ◽  
Random Decrement Technique ◽  
Cable Stayed Bridge ◽  
Vibration Responses ◽  
Cable Vibrations

The structural health monitoring system (SHMS) provides an effective tool to conduct full-scale measurements on existing bridges for essential research on bridge wind engineering. In July 2008, Typhoon Fung-Wong lashed China and hit Sutong cable-stayed bridge (SCB) in China. During typhoon period, full-scale measurements were conducted to record the wind data and the structural vibration responses were collected by the SHMS installed on SCB. Based on the statistical method and the spectral analysis technique, the measured data are analyzed to obtain the typical parameters and characteristics. Furthermore, this paper analyzed the measured structural vibration responses and indicated the vibration characteristics of the stay cable and the deck, the relationship between structural vibrations and wind speed, the comparison of upstream and downstream cable vibrations, the effectiveness of cable dampers, and so forth. Considering the significance of damping ratio in vibration mitigation, the modal damping ratios of the SCB are identified based on the Hilbert-Huang transform (HHT) combined with the random decrement technique (RDT). The analysis results can be used to validate the current dynamic characteristic analysis methods, buffeting calculation methods, and wind tunnel test results of the long-span cable-stayed bridges.

The Role of Medical Management for Acute Intravascular Hemolysis in Patients Supported on Axial Flow LVAD

ASAIO Journal ◽  
2014 ◽  
Vol 60 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Tal Hasin ◽  
Salil Deo ◽  
Joseph J. Maleszewski ◽  
Yan Topilsky ◽  
Brooks S. Edwards ◽  
...  
Keyword(s):  
Medical Management ◽  
Axial Flow ◽  
Intravascular Hemolysis

Field observation of vortex- and rain-wind-induced stay-cable vibrations in a three-dimensional environment

2008 ◽  
Vol 96 (6-7) ◽  
pp. 1124-1133 ◽  
Author(s):  
D. Zuo ◽  
N.P. Jones ◽  
J.A. Main
Keyword(s):  
Field Observation ◽  
Three Dimensional ◽  
Stay Cable ◽  
Cable Vibrations

Multi-mode control performance of nonlinear dampers in stay cable vibrations

2009 ◽  
pp. n/a-n/a ◽  
Author(s):  
Nam Hoang ◽  
Yozo Fujino
Keyword(s):  
Control Performance ◽  
Stay Cable ◽  
Mode Control ◽  
Cable Vibrations ◽  
Multi Mode

Analysis, Measurement, and Mitigation of Stay Cable Vibrations

2018 ◽  
Author(s):  
A. Jain ◽  
C. Simsir ◽  
Partha P. Sarkar
Keyword(s):  
Stay Cable ◽  
Analysis Measurement ◽  
Cable Vibrations

Optimal Design of Dampers for Multi-Mode Cable Vibration Control Based on Genetic Algorithm

2021 ◽  
pp. 2150058
Author(s):  
Fangdian Di ◽  
Lin Chen ◽  
Limin Sun
Keyword(s):  
Genetic Algorithm ◽  
Vibration Control ◽  
Performance Optimization ◽  
Negative Stiffness ◽  
Stay Cable ◽  
Control Effect ◽  
Cable Vibration ◽  
Cable Vibrations ◽  
Damper Design ◽  
Multi Mode

Cables in cable-stayed bridges are subjected to the problem of multi-mode vibrations. Particularly, the first ten modes of long cables can have a frequency less than 3[Formula: see text]Hz and hence are vulnerable to wind-rain induced vibrations. In practice, mechanical dampers are widely used to mitigate such cable vibrations and thus they have to be designed to provide sufficient damping for all the concerned vibration modes. Meanwhile, the behaviors of practical dampers are complicated and better to be described by mechanical models with many parameters. Furthermore, additional mechanical components such as inerters and negative stiffness devices have been proposed to enhance the damper performance on cables. Therefore, it is increasingly difficult to optimize the damper parameters for suppressing multi-mode cable vibrations. To address this issue, this study proposes a novel damper design method based on the genetic algorithm (GA). The procedure of the method is first introduced where the damper performance optimization is formulated as a single-objective multi-parameter optimization problem. The effectiveness of the method is then verified by considering a viscous damper on a stay cable. Subsequently, the method is applied to optimize three typical dampers for cable vibration control, i.e. the positive stiffness damper, the negative stiffness damper, and the viscous inertial mass damper. The results show that the GA-based method is effective and efficient for cable damper design to achieve best multi-mode control effect and it is particularly useful for dampers with more parameters.

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