Complex Wavespeed and Hydraulic Transients in Viscoelastic Pipes

1990 ◽  
Vol 112 (4) ◽  
pp. 496-500 ◽  
Author(s):  
Lisheng Suo ◽  
E. B. Wylie
Keyword(s):  
Experimental Data ◽  
Wave Propagation ◽  
Transfer Matrix ◽  
Impulse Response ◽  
Pipe Wall ◽  
Wall Material ◽  
Hydraulic Transients ◽  
Response Method ◽  
Complex Valued ◽  
Good Agreement

The classic formula for waterhammer wavespeed is extended to calculate the complex-valued, frequency-dependent wavespeed in a viscoelastic pipe, which takes into account the effect of viscoelasticity of pipe wall material on wave propagation. With the complex wavespeed, the standard impedance or transfer matrix is directly used to analyze resonating conditions in systems including viscoelastic pipes, and the impulse response method presented previously by the authors is applied to compute nonperiodic transients. Numerical results are compared with experimental data and good agreement is observed.

Simulation of the Ultrasonic Diffraction in Viscous Fluids

2003 ◽  
Author(s):  
N. Bouaoua ◽  
A. Alia ◽  
H. Djelouah
Keyword(s):  
Finite Difference ◽  
Viscous Fluid ◽  
Impulse Response ◽  
Acoustic Radiation ◽  
Viscous Fluids ◽  
Attenuation Effect ◽  
Ultrasonic Diffraction ◽  
Response Method ◽  
Good Agreement

In this paper, Impulse Response Method (IRM) and Finite Difference (FD) are used to model the acoustic radiation in a viscous fluid where the attenuation is obeying a squared frequency law. Some results are presented to illustrate the attenuation effect on the diffraction. A good agreement between the IRM results and those numerically predicted by FDM is observed.

Complete Transient Two-Dimensional Analysis of Two-Phase Closed Thermosyphons Including the Falling Condensate Film

1994 ◽  
Vol 116 (2) ◽  
pp. 418-426 ◽  
Author(s):  
C. Harley ◽  
A. Faghri
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Conjugate Heat Transfer ◽  
Pipe Wall ◽  
Vapor Flow ◽  
Two Dimensional ◽  
Type Solution ◽  
Two Phase ◽  
Condensate Film ◽  
Good Agreement

A transient two-dimensional thermosyphon model is presented that accounts for conjugate heat transfer through the wall and the falling condensate film. The complete transient two-dimensional conservation equations are solved for the vapor flow and pipe wall, and the liquid film is modeled using a quasi-steady Nusselt-type solution. The model is verified by comparison with existing experimental data for a low-temperature thermosyphon with good agreement. A typical high-temperature thermosyphon was then simulated to examine the effects of vapor compressibility and conjugate heat transfer.

Identification of Excitation Forces and Prediction of the Radiation by Measured Structural Vibrations from an Underwater Structure

2013 ◽  
Vol 457-458 ◽  
pp. 1139-1143
Author(s):  
Ji Gang ◽  
Q. Zhou ◽  
Chun Wen Huang
Keyword(s):  
Experimental Data ◽  
Frequency Domain ◽  
Transfer Matrix ◽  
Numerical Results ◽  
Structural Vibrations ◽  
Cylindrical Model ◽  
Underwater Structure ◽  
Good Agreement

An approach identifying the excitation forces based on structural vibrations measured is proposed in the paper. Based on the transfer matrix predicted by FEM/BEM and the vibration vector measured, excitation forces in frequency domain are identified. Further more, acoustic from the underwater structure is predicted by FEM/BEM. To verify the approach, experiment on was carried out for a shaker driven underwater immerged cylindrical model made of steel. Excitations are identified by accelerations measured on the shell. With the forces provided, the radiation of the shell is predicted and compared with that measured. The numerical results are shown to be in good agreement with experimental data.

Energy Levels and Electromagnetic Transition of 90-94mo Nuclei Using Ibm-1

2020 ◽  
pp. 149-152
Keyword(s):  
Experimental Data ◽  
Transition Probability ◽  
Energy Levels ◽  
Dynamical Symmetry ◽  
Interacting Boson Model ◽  
Excitation Energies ◽  
Electromagnetic Transition ◽  
Boson Model ◽  
Energy States ◽  
Good Agreement

The energy states for the J , b , ɤ bands and electromagnetic transitions B (E2) values for even – even molybdenum 90 – 94 Mo nuclei are calculated in the present work of "the interacting boson model (IBM-1)" . The parameters of the equation of IBM-1 Hamiltonian are determined which yield the best excellent suit the experimental energy states . The positive parity of energy states are obtained by using IBS1. for program for even 90 – 94 Mo isotopes with bosons number 5 , 4 and 5 respectively. The" reduced transition probability B(E2)" of these neuclei are calculated and compared with the experimental data . The ratio of the excitation energies of the 41+ to 21+ states ( R4/2) are also calculated . The calculated and experimental (R4/2) values showed that the 90 – 94 Mo nuclei have the vibrational dynamical symmetry U(5). Good agreement was found from comparison between the calculated energy states and electric quadruple probabilities B(E2) transition of the 90–94Mo isotopes with the experimental data .

On a technique for deriving explicit transfer matrices of orthotropic layers

2015 ◽  
Vol 37 (4) ◽  
pp. 303-315 ◽  
Author(s):  
Pham Chi Vinh ◽  
Nguyen Thi Khanh Linh ◽  
Vu Thi Ngoc Anh
Keyword(s):  
Wave Propagation ◽  
Explicit Form ◽  
Half Space ◽  
Transfer Matrix ◽  
Rayleigh Waves ◽  
Secular Equation ◽  
Transfer Matrices ◽  
Orthotropic Layer ◽  
Wave Propagation Problem ◽  
Arbitrary Thickness

This paper presents  a technique by which the transfer matrix in explicit form of an orthotropic layer can be easily obtained. This transfer matrix is applicable for both the wave propagation problem and the reflection/transmission problem. The obtained transfer matrix is then employed to derive the explicit secular equation of Rayleigh waves propagating in an orthotropic half-space coated by an orthotropic layer of arbitrary thickness.

Predicting the Effect of Tire Tread Pattern Design on Thick Film Wet Traction

1977 ◽  
Vol 5 (1) ◽  
pp. 6-28 ◽  
Author(s):  
A. L. Browne
Keyword(s):  
Experimental Data ◽  
Network Design ◽  
Thick Film ◽  
Digital Computer ◽  
Analytical Tool ◽  
Design Practice ◽  
Pattern Design ◽  
Performance Results ◽  
Good Agreement

Abstract An analytical tool is presented for the prediction of the effects of changes in tread pattern design on thick film wet traction performance. Results are reported for studies in which the analysis, implemented on a digital computer, was used to determine the effect of different tread geometry features, among these being the number, width, and lateral spacing of longitudinal grooves and the angle of zigzags in longitudinal grooves, on thick film wet traction. These results are shown to be in good agreement with experimental data appearing in the literature and are used to formulate guidelines for tread groove network design practice.

A New Condition of Formation and Stablity of All Crystalline Systems in a Good Agreement with Experimental Data

2015 ◽  
Vol 11 (3) ◽  
pp. 3224-3228
Author(s):  
Tarek El-Ashram
Keyword(s):  
Experimental Data ◽  
Brillouin Zone ◽  
Electron Concentration ◽  
Free Electron ◽  
Lattice Point ◽  
Valence Electron ◽  
Fermi Gas ◽  
Valence Electron Concentration ◽  
Fermi Sphere ◽  
Good Agreement

In this paper we derived a new condition of formation and stability of all crystalline systems and we checked its validity andit is found to be in a good agreement with experimental data. This condition is derived directly from the quantum conditionson the free electron Fermi gas inside the crystal. The new condition relates both the volume of Fermi sphere VF andvolume of Brillouin zone VB by the valence electron concentration VEC as ;𝑽𝑭𝑽𝑩= 𝒏𝑽𝑬𝑪𝟐for all crystalline systems (wheren is the number of atoms per lattice point).

Effect of leakage and blockage on the acoustic behavior of particle filters

2019 ◽  
Vol 67 (6) ◽  
pp. 483-492
Author(s):  
Seonghyeon Baek ◽  
Iljae Lee
Keyword(s):  
Transfer Matrix ◽  
Particle Filters ◽  
Acoustic Analysis ◽  
Transmission Loss ◽  
One Dimensional ◽  
Filter System ◽  
The Difference ◽  
The One ◽  
Analytical Approaches ◽  
Good Agreement

The effects of leakage and blockage on the acoustic performance of particle filters have been examined by using one-dimensional acoustic analysis and experimental methods. First, the transfer matrix of a filter system connected to inlet and outlet pipes with conical sections is measured using a two-load method. Then, the transfer matrix of a particle filter only is extracted from the experiments by applying inverse matrices of the conical sections. In the analytical approaches, the one-dimensional acoustic model for the leakage between the filter and the housing is developed. The predicted transmission loss shows a good agreement with the experimental results. Compared to the baseline, the leakage between the filter and housing increases transmission loss at a certain frequency and its harmonics. In addition, the transmission loss for the system with a partially blocked filter is measured. The blockage of the filter also increases the transmission loss at higher frequencies. For the simplicity of experiments to identify the leakage and blockage, the reflection coefficients at the inlet of the filter system have been measured using two different downstream conditions: open pipe and highly absorptive terminations. The experiments show that with highly absorptive terminations, it is easier to see the difference between the baseline and the defects.

Virus Removal by Filtration

1982 ◽  
Vol 14 (4-5) ◽  
pp. 253-256
Author(s):  
N Sriramula ◽  
M Chaudhuri
Keyword(s):  
Experimental Data ◽  
Escherichia Coli ◽  
Cationic Polyelectrolyte ◽  
Electrokinetic Phenomena ◽  
Virus Removal ◽  
Bacterial Virus ◽  
Gravity Settling ◽  
And Diffusion ◽  
Model Virus ◽  
Good Agreement

An investigation was undertaken on the removal of a model virus, bacterial virus MS2 against Escherichia coli, by sand filtration using untreated, and alum or cationic polyelectrolyte treated media, and uncoagulated as well as alum coagulated influent. Data on discrete virus removal were satisfactorily accounted for by electrokinetic phenomena and diffusion. For virus in association with turbidity, filter coefficients computed from experimental data were in good agreement with those predicted by mechanical straining and gravity settling which were the dominant mechanisms for removal of the turbidity particles to which the viruses attached.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

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