ON THE ACOUSTIC RADIATION FIELD OF THE PIEZO-ELECTRIC OSCILLATOR AND THE EFFECT OF VISCOSITY ON TRANSMISSION: PART II

1934 ◽  
Vol 11 (4) ◽  
pp. 484-488 ◽  
Author(s):  
L. V. King
Keyword(s):  
Radiation Field ◽  
Sea Water ◽  
Acoustic Radiation ◽  
Wave Length ◽  
Numerical Data ◽  
Transmission Part ◽  
Coefficient Of Viscosity ◽  
Theoretical Results ◽  
Piezo Electric

Numerical data on the distance of transmission of sound in sea water from a 10-in. piezo-electric oscillator are discussed in the light of theoretical results obtained in a previous paper. It is shown how by the principle of similitude the chart for transmission at optimum wave-length calculated for a 50-watt, 60 cm. oscillator can be used for a transmitter of any given diameter and output. A comparison with some experiments of Boyle's points to the fact that at supersonic frequencies, in the neighborhood of 100,000 cycles, a considerably higher coefficient of viscosity than that obtained by flow methods must be used.

ON THE ACOUSTIC RADIATION FIELD OF THE PIEZO-ELECTRIC OSCILLATOR AND THE EFFECT OF VISCOSITY ON TRANSMISSION

1934 ◽  
Vol 11 (2) ◽  
pp. 135-155 ◽  
Author(s):  
Louis V. King
Keyword(s):  
Radiation Field ◽  
Velocity Potential ◽  
Marked Effect ◽  
Acoustic Radiation ◽  
Wave Length ◽  
Practical Importance ◽  
Circular Disc ◽  
Circular Aperture ◽  
Constant Output ◽  
Infinite Integral

The radiation field due to a circular disc oscillating with uniform amplitude in a closely fitting circular aperture surrounded by an infinite rigid flange has been studied in detail, the velocity potential being expressed as an infinite integral involving cylindrical co-ordinates. The procedure adopted may be used to study the effect of viscosity on the characteristics of the radiation field. While having little effect on the field in the neighborhood of an oscillator generating waves in water, the viscosity has a marked effect on the range of distant transmission, which in consequence is appreciably affected by temperature. Of considerable practical importance is the existence of an optimum wave-length for constant output and a given distance of transmission. By means of a simple chart, it is possible to determine the optimum wave-length for a given transmitter when the level of reception for a given range is stated.

An experimental study of the scattering of light by natural waters

1952 ◽  
Vol 140 (900) ◽  
pp. 321-338 ◽  
Keyword(s):  
Surface Water ◽  
Natural Waters ◽  
Cold Water ◽  
Sea Water ◽  
Tap Water ◽  
Wave Length ◽  
Average Pore ◽  
Forward Scatter ◽  
Back Scattering ◽  
Similar Sample

A blue-sensitive multiplier phototube was used to measure light scattered from a parallel beam in distilled, tap and sea water, the first named serving as a check upon errors from extraneous sources of light. Forward and back scatter are closely the same for distilled water, but with natural waters by far the greater part of the effect occurs through angles less than 25°. A minimum is found for a deviation of about 110°, back scattering increasing somewhat for greater angles. The relative importance of forward scatter increases with turbidity, and in sea water about three-quarters of the effect is due to matter removable by filtration through a collodion filter of average pore diameter 1 μ or by sedimentation; further passage through 0·6 and 0·2 μ filters produces little change. Scattering is greater in blue light. Plymouth tap water scatters more than surface coastal water and the latter more than surface water 20 miles out, station E 1. Surface water scatters more than deeper—the water column being remarkably homogeneous even when a well-marked thermocline had existed for weeks, but a small increase was detectable at the top of the cold water. E 1 surface water increased in scattering between August and January, and decreased till May. Deep water showed little change. Extinction due to scattering between 20 and 155° amounted to less than one-sixth of that found for a similar sample with a Pulfrich photometer, so probably much scattering occurs below 20°. This explains why Pulfrich extinctions are so much greater than vertical extinction coefficients found in the sea. The preponderance of forward scattering within the range 20 to 155° and the effects of filtration suggest that such scattering is due chiefly to refraction through transparent mineral particles, large compared with the wave-length of light. The refractive index of organic matter is too near that of water to produce refraction through angles as large as 20°. Such matter may, however, be responsible for some of the scattering through smaller angles which apparently accounts for most of the turbidity found with the Pulfrich photometer.

Numerical Analysis of a New-Style Ultrasonic Linear Array

2011 ◽  
Vol 58-60 ◽  
pp. 1043-1048
Author(s):  
Yong Wang ◽  
Quan Lu Li
Keyword(s):  
Numerical Analysis ◽  
Radiation Field ◽  
Acoustic Field ◽  
Linear Array ◽  
Acoustic Radiation ◽  
Acoustic Lens ◽  
Width Direction

In order to reduce the field of the acoustic radiation and improve the efficiency of energy using, a new-style ultrasonic linear array is present, which base on the special structural of the acoustic field produced by the cylindrical acoustic lens. The new-style linear array is composed of numbers of cylindrical acoustic lens, each lens act as an element distributed in a line along the width direction. Define x-direction is the direction of wave propagate. We have studied the acoustic field theoretically and have analyzed it numerically. Found that acoustic field have a better directivity in y-direction and the radiation field is much smaller than the traditional linear array, at the same time the focus ability is appear in the Z-direction if we control the number of element and the distance of center-to-center spacing of each element. This paper is helpful to the change and development of traditional liner array.

scholarly journals Study of SH acoustic radiation field excited by a piezoelectric strip

2005 ◽  
Vol 54 (5) ◽  
pp. 2111
Author(s):  
Zhang Bi-Xing ◽  
Wang Cheng-Hao ◽  
Bostrm Anders
Keyword(s):  
Radiation Field ◽  
Acoustic Radiation ◽  
Piezoelectric Strip

scholarly journals EXPERIMENTAL INVESTIGATIONS OF ACOUSTIC RADIATION PULSES CYLINDRICAL PIEZOELECTRIC TRANSDUCERS LOCATED IN A LIQUID

2013 ◽  
pp. 68-74
Author(s):  
В. Г. Савин ◽  
Н. И. Штефан ◽  
А. А. Бабаев
Keyword(s):  
Mathematical Models ◽  
Acoustic Radiation ◽  
Block Diagram ◽  
Theoretical Work ◽  
Analytical Form ◽  
Piezoelectric Transducers ◽  
Measuring System ◽  
Experimental Investigations ◽  
Cylindrical Transducer ◽  
Theoretical Results

 Discusses issues related to the comparison of the experimental and theoretical results , that is, of acoustic pulses cylindrical piezoelectric transducers that are in the liquid.Electrical block diagram of the measuring system is the base for conducting such research. When this converter is excited at a resonant frequency.Analyzing the experimental and theoretical results, it should be noted that the formulation of the problem was carried out in an analytical form. Formulation and solution of the problem allow us to find the physical characteristics of the studied transition.Based on a comparison of experimental and theoretical work in the conclusion of the applicability of the results in practice, the proposed mathematical models of cylindrical piezoelectric transducers (thin electroelastic bodies), based on the linear theory of electrodynamics and of the Kirchhoff – Love in the time-dependent problems in calculating hydro acoustic transducers.Experimental studies were carried out for commercially available cylindrical transducer brand TSTBS – 3 is in the liquid, and the considered regimes of pulsed electrical excitation are working for most of sonar systems. Tests have shown that the actual design features of the considered cylindrical transducer little effect on the configuration of the acoustic pulses of radiation in different directions. Applied mathematical models of thin electroelastic bodies are recommended for use in the design practice in the design of sonar technology for various purposes.The study of the transition process is relevant for the decision of problems like these.

scholarly journals Simple Theoretical Results on Reversible Fouling in Cross-Flow Membrane Filtration

Membranes ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 48
Author(s):  
Pierre Haldenwang ◽  
Braulio Bernales ◽  
Pierrette Guichardon ◽  
Nelson Ibaseta
Keyword(s):  
Membrane Filtration ◽  
Critical Concentration ◽  
Cross Flow ◽  
Numerical Data ◽  
Physical Parameters ◽  
Additional Parameter ◽  
Feed Concentration ◽  
Dimensional Parameter ◽  
Viscous Pressure ◽  
Theoretical Results

In cross-flow membrane filtration, fouling results from material deposit which clogs the membrane inner surface. This hinders filtration, which experiences the so-called limiting flux. Among the models proposed by the literature, we retain a simple one: a steady-state reversible fouling is modelled with the use of a single additional parameter, i.e., N d , the ratio of the critical concentration for deposition to the feed concentration at inlet. To focus on fouling, viscous pressure drop and osmotic (counter-)pressure have been chosen low. It results in a minimal model of fouling. Solved thoroughly with the numerical means appropriate to enforce the nonlinear coupling between permeation and concentration polarization, the model delivers novel information. It first shows that permeation is utterly governed by solute transfer, the relevant non-dimensional quantities being hence limited to N d and P e i n , the transverse Péclet number. Furthermore, when the role played by N d and moderate P e i n (say P e i n < 40 ) is investigated, all results can be interpreted with the use of a single non-dimensional parameter, F l , the so-called fouling number, which simply reads F l ≡ P e i n N d - 1 . Now rendered possible, the overall fit of the numerical data allows us to put forward analytical final expressions, which involve all the physical parameters and allow us to retrieve the experimental trends.

The Design and Realization of the Visualization System of Acoustic Radiation Based on NAH

2012 ◽  
Vol 271-272 ◽  
pp. 1451-1454
Author(s):  
Lin Na Zhou ◽  
Jing Jun Lou ◽  
Shi Jian Zhu
Keyword(s):  
Data Management ◽  
Radiation Field ◽  
Acoustic Radiation ◽  
Complete Solution ◽  
Measurement Data ◽  
Visualization System ◽  
Visualization Technology

The characteristic of the acoustic radiation of vibrating structure is the important factor in valuing its performance. This paper puts forward a visualization system of the acoustic radiation based on NAH which combines the measurement, data management and visualization. The visualization technology it adopts point a new way to the observation of the acoustic radiation. Experiments have shown that this system can offer a complete solution for the measurement and research of the radiation field.

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