Acoustic Vibration in a Stack Induced by Pipe Bends

2002 ◽  
Author(s):  
F. L. Eisinger ◽  
R. E. Sullivan ◽  
P. Feenstra ◽  
D. S. Weaver
Keyword(s):  
Acoustic Wave ◽  
Turbulent Flow ◽  
Pure Tone ◽  
Guide Vane ◽  
Acoustic Vibration ◽  
Model Tests ◽  
Laboratory Scale ◽  
Scale Model ◽  
Residential Areas ◽  
Guide Vanes

Acoustic vibration in two stack liners located inside a stack downstream of two induced draft fans occurred at high loads. Measurements confirmed that an acoustic wave developed in the fundamental diametral mode of the cylindrical stack liners. It manifested itself as a pure tone traveling through the stack to surrounding residential areas. It was suspected that turbulent flow in the pipe bends upstream of the stack and downstream of the fans was the source of the excitation. Laboratory scale model tests confirmed that the bends indeed acted as the source. Two guide vane configurations placed inside the bends were tested experimentally. The tests showed that properly placed guide vanes would reduce the acoustic levels in the stack. The paper gives a description and evaluation of the problem.

Acoustic Vibration in a Stack Induced by Pipe Bends

2003 ◽  
Vol 125 (2) ◽  
pp. 228-232 ◽  
Author(s):  
F. L. Eisinger ◽  
R. E. Sullivan ◽  
P. Feenstra ◽  
D. S. Weaver
Keyword(s):  
Acoustic Wave ◽  
Turbulent Flow ◽  
Pure Tone ◽  
Guide Vane ◽  
Acoustic Vibration ◽  
Model Tests ◽  
Laboratory Scale ◽  
Scale Model ◽  
Residential Areas ◽  
Guide Vanes

Acoustic vibration in two stack liners located inside a stack downstream of two induced draft fans occurred at high loads. Measurements confirmed that an acoustic wave developed in the fundamental diametral mode of the cylindrical stack liners. It manifested itself as a pure tone traveling through the stack to surrounding residential areas. It was suspected that turbulent flow in the pipe bends upstream of the stack and downstream of the fans was the source of the excitation. Laboratory scale model tests confirmed that the bends indeed acted as the source. Two guide vane configurations placed inside the bends were tested experimentally. The tests showed that properly placed guide vanes would reduce the acoustic levels in the stack. The paper gives a description and evaluation of the problem.

Guide Vane Vibrations Caused by Wakes and Blower Noise—Part 2: Transferability From the Model to the Prototype

1976 ◽  
Vol 98 (3) ◽  
pp. 956-964
Author(s):  
Y. N. Chen ◽  
G. Baylac ◽  
R. Walther
Keyword(s):  
Model Test ◽  
Dynamic Stress ◽  
Guide Vane ◽  
Mechanical Vibration ◽  
Phase Relationship ◽  
Acoustic Resonance ◽  
Model Tests ◽  
Guide Vanes ◽  
Excited Vibration ◽  
Relationship Of

Model tests were carried out on vibrations of guide vanes induced by wakes and noise. The results will be compared with the measurements on the prototype. It will be shown that the modeling law applies well for the wake-induced vibration. But for the noise-excited vibration, the model test with the loudspeaker noise gave too high a level of the dynamic stress compared with that in the prototype excited by the blower noise. This deviation can be attributed to the unsteady phase relationship of the noise generated by the turbomachinery. The acoustic resonances in the channels will be investigated both theoretically and experimentally. A damping of these resonances can be achieved by inserting cross plates into a part of the channel. The mechanical vibration of a turning blade can only be severely excited by the noise, as long as an acoustic resonance prevails in a neighboring channel near the corresponding frequency.

scholarly journals Advanced Instrumentation for Measuring Fluid-Structure Coupling Phenomena in the Guide Vanes Cascade of a Pump-Turbine Scale Model

2010 ◽  
Author(s):  
Steven Roth ◽  
Vlad Hasmatuchi ◽  
Francisco Botero ◽  
Mohamed Farhat ◽  
Francois Avellan
Keyword(s):  
Guide Vane ◽  
Pressure Sensors ◽  
Scale Model ◽  
Laser Vibrometer ◽  
Strain Gages ◽  
Structural Vibrations ◽  
Pump Turbine ◽  
Fluid Structure ◽  
Guide Vanes ◽  
Coupling Phenomena

In the present study, the fluid-structure coupling is investigated in the guide vanes cascade of a pump-turbine scale model placed in the EPFL PF3 test rig. The paper focuses on the advanced instrumentation used to get reliable and complete fluid-structure coupling results. Semi-conductor strain gages are installed on three guide vanes which are especially weakened to account for stronger fluid-structure coupling phenomena. These are statically calibrated in terms of torsion torque and bending force. A laser vibrometer is used to measure the vibrating guide vane velocity. Piezo-resistive pressure sensors are placed around the weakened guide vanes to monitor the influence of the structural vibrations on the surrounding flow. An underwater non-intrusive system is used to get an impulse excitation. The instrument set enables a reliable fluid-structure coupling investigation in hydraulic pump-turbine scale model. Finally, the results show a strong coupling between the vibrating guide vanes and the surrounding unsteady flow.

scholarly journals EXTREME WAVE PRESSURES AND LOADS ON A PILE-SUPPORTED WHARF DECK - INFLUENCES OF AIR GAP AND WAVE DIRECTION

2018 ◽  
pp. 5
Author(s):  
Andrew Cornett
Keyword(s):  
Offshore Structures ◽  
Model Tests ◽  
Scale Model ◽  
Extreme Waves ◽  
Wave Direction ◽  
Coastal Structures ◽  
Extreme Wave ◽  
Wave Impact ◽  
The Past ◽  
Water Depths

Many deck-on-pile structures are located in shallow water depths at elevations low enough to be inundated by large waves during intense storms or tsunami. Many researchers have studied wave-in-deck loads over the past decade using a variety of theoretical, experimental, and numerical methods. Wave-in-deck loads on various pile supported coastal structures such as jetties, piers, wharves and bridges have been studied by Tirindelli et al. (2003), Cuomo et al. (2007, 2009), Murali et al. (2009), and Meng et al. (2010). All these authors analyzed data from scale model tests to investigate the pressures and loads on beam and deck elements subject to wave impact under various conditions. Wavein- deck loads on fixed offshore structures have been studied by Murray et al. (1997), Finnigan et al. (1997), Bea et al. (1999, 2001), Baarholm et al. (2004, 2009), and Raaij et al. (2007). These authors have studied both simplified and realistic deck structures using a mixture of theoretical analysis and model tests. Other researchers, including Kendon et al. (2010), Schellin et al. (2009), Lande et al. (2011) and Wemmenhove et al. (2011) have demonstrated that various CFD methods can be used to simulate the interaction of extreme waves with both simple and more realistic deck structures, and predict wave-in-deck pressures and loads.

Large scale model tests on Royal Schelde SES

1989 ◽  
Author(s):  
R. DE GAAIJ ◽  
E. VAN RIETBERGEN ◽  
M. SLEGERS
Keyword(s):  
Large Scale ◽  
Model Tests ◽  
Scale Model ◽  
Large Scale Model

Large eddy simulation study of turbulent flow around smooth and rough domes

2013 ◽  
Vol 227 (12) ◽  
pp. 2686-2700 ◽  
Author(s):  
N Kharoua ◽  
L Khezzar
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Flow ◽  
Flow Behavior ◽  
Pressure Coefficient ◽  
Horseshoe Vortex ◽  
Scale Model ◽  
Stream Velocity ◽  
Mean Velocity ◽  
Eddy Simulation ◽  
Large Eddy

Large eddy simulation of turbulent flow around smooth and rough hemispherical domes was conducted. The roughness of the rough dome was generated by a special approach using quadrilateral solid blocks placed alternately on the dome surface. It was shown that this approach is capable of generating the roughness effect with a relative success. The subgrid-scale model based on the transport of the subgrid turbulent kinetic energy was used to account for the small scales effect not resolved by large eddy simulation. The turbulent flow was simulated at a subcritical Reynolds number based on the approach free stream velocity, air properties, and dome diameter of 1.4 × 105. Profiles of mean pressure coefficient, mean velocity, and its root mean square were predicted with good accuracy. The comparison between the two domes showed different flow behavior around them. A flattened horseshoe vortex was observed to develop around the rough dome at larger distance compared with the smooth dome. The separation phenomenon occurs before the apex of the rough dome while for the smooth dome it is shifted forward. The turbulence-affected region in the wake was larger for the rough dome.

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