Side Branch Interaction With Main Line Standing Waves and Related Component Load Definition

2009 ◽  
Author(s):  
Arthur Ruggles ◽  
Eric M. Moore ◽  
Michael Shehane ◽  
Bi Yao Zhang ◽  
John Sparger
Keyword(s):  
Standing Wave ◽  
Dynamic Pressure ◽  
Standing Waves ◽  
Side Branch ◽  
Main Line ◽  
Test Facility ◽  
Time Data ◽  
Resonant Amplitude ◽  
Acoustic Boundary Condition ◽  
Signal Features

Side branch resonance can cause standing waves in the main line. The main line standing wave modifies the acoustic boundary condition between the side branch and the main line. This interaction leads to drift in the side branch resonant frequency, and to sensitivity in the side branch and main line resonant amplitude as a function of branch position along the main line standing wave. In many cases the mainline standing wave is not stationary, leading to temporal modulation of the side branch frequency and amplitude. These features are examined using novel signal interrogation techniques that expose frequency and amplitude variation in time. Data from a low pressure air test facility are used to reinforce the theory and demonstrate the system behavior. Finally, the connection between the dynamic pressure signal features and methods for main line and branch component endurance prediction is developed. Components such as steam dryers, safety relief valves, and heat exchangers would be candidates for endurance prediction using these methods.

scholarly journals Side Branch Interaction with Main Line Standing Waves and Related Signal Handling Approaches

2013 ◽  
Vol 2013 ◽  
pp. 1-9
Author(s):  
Arthur Ruggles ◽  
Eric M. Moore ◽  
Michael Shehane
Keyword(s):  
Time History ◽  
Side Branch ◽  
Acoustic Energy ◽  
Main Line ◽  
Test Facility ◽  
Resonance Amplitude ◽  
Resonance Behavior ◽  
Power Spectral ◽  
Power Spectral Densities

Data from a low pressure air test facility are used to quantify the influence of the acoustic field in the main line on side branch resonance behavior. The main line of diameter = 7.6 cm may accumulate acoustic energy broadcast from a resonating branch of diameter = 1.9 cm ( = 0.25). The side branch resonance amplitude is a strong function of branch position along the main line with the normalized pressure rising to 1.2 in the most favorable branch positions with Strouhal number near 0.3. Large time variation of the side branch and main line resonance amplitude is apparent for most branch positions. A moving window is used on the time history to collect an array of power spectral densities (PSDs). Peak amplitude values from the PSD array are represented in a probability density function (PDF) that provides a repeatable characterization of data from the system.

scholarly journals Instability of standing waves for non-linear Schrödinger-type equations

1988 ◽  
Vol 8 (8) ◽  
pp. 119-138 ◽  
Keyword(s):  
Dynamical Systems ◽  
Standing Wave ◽  
Optical Waveguides ◽  
Standing Waves ◽  
Positive Eigenvalue ◽  
Shooting Argument ◽  
Wave Solutions ◽  
Non Linear ◽  
Linearized Operator

AbstractA theorem is proved giving a condition under which certain standing wave solutions of non-linear Schrödinger-type equations are linearly unstable. The eigenvalue equations for the linearized operator at the standing wave can be analysed by dynamical systems methods. A positive eigenvalue is then shown to exist by means of a shooting argument in the space of Lagrangian planes. The theorem is applied to a situation arising in optical waveguides.

On the observability of finite-depth short-crested water waves

1996 ◽  
Vol 322 ◽  
pp. 1-19 ◽  
Author(s):  
M. Ioualalen ◽  
A. J. Roberts ◽  
C. Kharif
Keyword(s):  
Standing Wave ◽  
Water Waves ◽  
Numerical Study ◽  
Standing Waves ◽  
Finite Depth ◽  
Two Dimensional ◽  
Wave Fields ◽  
Progressive Waves ◽  
Wave Limit ◽  
Narrow Bands

A numerical study of the superharmonic instabilities of short-crested waves on water of finite depth is performed in order to measure their time scales. It is shown that these superharmonic instabilities can be significant-unlike the deep-water case-in parts of the parameter regime. New resonances associated with the standing wave limit are studied closely. These instabilities ‘contaminate’ most of the parameter space, excluding that near two-dimensional progressive waves; however, they are significant only near the standing wave limit. The main result is that very narrow bands of both short-crested waves ‘close’ to two-dimensional standing waves, and of well developed short-crested waves, perturbed by superharmonic instabilities, are unstable for depths shallower than approximately a non-dimensional depth d= 1; the study is performed down to depth d= 0.5 beyond which the computations do not converge sufficiently. As a corollary, the present study predicts that these very narrow sub-domains of short-crested wave fields will not be observable, although most of the short-crested wave fields will be.

A New Micro Turbo-Machinery Test Facility

2010 ◽  
Author(s):  
Chen Xia ◽  
Guoping Huang ◽  
Jie Chen
Keyword(s):  
Mass Flow ◽  
High Speed ◽  
Modular Design ◽  
Thermal Protection ◽  
Dynamic Pressure ◽  
Pressure Sensors ◽  
Test Facility ◽  
Inlet Temperature ◽  
Test Bed ◽  
Turbo Machinery

The design and construction of a new test facility of micro turbo-machinery are presented for micro centrifugal compressors and radial turbines. The bed can be used for the full speed compressor test and the long duration hot turbine test. In order to adjust the testing condition rapidly, all the regulations of operating state are completed automatically by the control system. The test bed can be used for testing impeller performance with a series of diameter from 55 to 180 mm as a result of the modular design. A thermal protection system is designed to avoid the heat distortion caused by the high inlet temperature of turbine which may exceeds 1100K and provide a proper experimental environment for the electronic components. A photoelectric torque transducer with an accuracy of 1% is designed to measure the torque of a rigid shaft at a high speed over 120000rpm, and the maximum shaft torque is 7.7 N·m. The pressure and temperature are measured by pressure probes and thermocouples. The dynamic pressure signal of the centrifugal compressor is monitored by dynamic pressure sensors. The V-cone pressure-difference mass-flow meters are used for measuring mass-flow. The maximum rotating speed is 125000rpm, and the mass flow adjusted by the electric control valves varies from 0.1 to 1.0 kg/sec. The maximum inlet total temperature of the turbine is 1180K.

scholarly journals Dimensional reduction in 6D standing waves braneworld

2014 ◽  
Vol 24 (01) ◽  
pp. 1550009 ◽  
Author(s):  
Otari Sakhelashvili
Keyword(s):  
Exact Solution ◽  
Standing Wave ◽  
Dimensional Reduction ◽  
Cosmological Solution ◽  
Standing Waves ◽  
Massless Scalar ◽  
Dynamical Mechanism ◽  
Higher Dimensional ◽  
Braneworld Model

We found cosmological solution of the 6D standing wave braneworld model generated by gravity coupled to a massless scalar phantom-like field. By obtaining a full exact solution of the model, we found a novel dynamical mechanism in which the anisotropic nature of the primordial metric gives rise to expansion of three spatial brane dimensions and affectively reduction of other spatial directions. This dynamical mechanism can be relevant for dimensional reduction in string and other higher-dimensional theories in the attempt of getting a 4D isotropic expanding spacetime.

Separation of Traveling and Standing Waves in a Rigid-Walled Circular Duct Containing an Intermediate Impedance Discontinuity

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Yongxiong Xiao ◽  
Antoine Blanchard ◽  
Yao Zhang ◽  
Huancai Lu ◽  
D. Michael McFarland ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Standing Waves ◽  
Side Branch ◽  
Element Analysis ◽  
Circular Duct ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Impedance Discontinuity

In this paper, we study the phenomenon of separation of traveling and standing waves in a one-dimensional rigid-walled circular duct. The underlying mechanism for separation, mode complexity, is linear and introduced here by a damped side branch representing an impedance discontinuity. The left end of the duct is driven at a single frequency by a harmonic acoustic source, and the right end is a rigid termination. The position and impedance of the side branch are independent parameters in the analysis. Sufficient conditions for acoustic wave separation in the duct are derived analytically and employed in a three-dimensional finite element analysis to verify the theoretical result. A physical experiment, consisting of a circular duct with a damped side branch, was constructed based on analytical predictions, the physical parameters were measured or identified, and its performance was documented. These experimental parameters were employed in a second three-dimensional finite element analysis to obtain a direct comparison with experimental results. The comparison reveals the extent to which higher-order (unmodeled) effects degrade the separation phenomenon. It is demonstrated that an intermediate damped side branch used as a nonresonant device can be predictively designed to achieve nearly ideal separation of traveling and standing waves in a rigid-walled circular duct in order to direct and control acoustic energy transmission through the duct system.

On Viscoelasticity and Standing Waves in Tires

1976 ◽  
Vol 4 (4) ◽  
pp. 233-246 ◽  
Author(s):  
J. Padovan
Keyword(s):  
Exact Solution ◽  
Standing Wave ◽  
Wave Phenomenon ◽  
Numerical Experiments ◽  
Standing Waves ◽  
Structural Damping ◽  
Resonance Response ◽  
Foundation Model ◽  
Stated Problem ◽  
Classical Ring

Abstract Based on the classical ring on foundation model for the tire, the effect which structural damping has on the development of the standing wave phenomenon is investigated. In particular, the model employed consists of a rotating ring on foundation where, in addition to including Coriolis effects, Kelvin-Voigt-type viscoelasticity is admitted in both the ring and foundation. Enforcing strict periodicity in space and time, the exact solution is obtained to the stated problem. Several parametric numerical experiments employing this solution are reported. These demonstrate that the standing wave phenomenon in tires is essentially a viscoelastic-type resonance response.

A smart device for particle separation in water using ultrasonic standing waves

2006 ◽  
Vol 6 (1) ◽  
pp. 173-183 ◽  
Author(s):  
Y.S. Lee ◽  
J.H. Kwon
Keyword(s):  
Standing Wave ◽  
Standing Waves ◽  
Smart Device ◽  
Zoom Lens ◽  
Electric Impedance ◽  
Separation Channel ◽  
Separation Device ◽  
Standing Wave Field ◽  
Ultrasonic Standing Wave ◽  
Separation Force

This paper presents the theory, design, and evaluation of a smart device for the enhanced separation of particles mixed in fluid. The smart device takes advantage of the ultrasonic standing wave, which was generated by the operation of a piezoceramic PZT patch installed in the smart device. The details of the device design including the electro-acoustical modelling for separation and PZT transducer are described. Based on this design, the separation device was fabricated and evaluated. In the experiments, an optical camera with a zoom lens was used to monitor the position of interested particles within the separation channel layer in the device. The electric impedance of the PZT patch bonded on the separation device was measured. The device shows a strong levitation and separation force against 50 μm diameter particles mixed with water at the separation channel in the device. Experimental results also showed that the device can work with both heavy and light sand particles mixed with water due to the generated standing wave field in the separation channel.

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