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Sunday, August 2, 2020 | History

3 edition of Propagation of sound waves in tubes of noncircular cross section found in the catalog.

Propagation of sound waves in tubes of noncircular cross section

# Propagation of sound waves in tubes of noncircular cross section

Subjects:
• Acoustic impedance.

• Edition Notes

The Physical Object ID Numbers Statement W. Bruce Richards. Series NASA technical paper -- 2601. Contributions United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch. Format Microform Pagination 1 v. Open Library OL14663892M

In working with sound propagation in a circular duct, the duct wall is often assumed to be rigid so that any pressure disturbance in the fluid has no effect on the wall. Consider a cross section of a half tube with diameter D, thickness h and tension T, Unlike 1-D wave propagation in a rigid duct where the propagation speed is a. propagation of the wave (sound) can be helpful. When the rod is stroke at the end there (exactly like a tube which is closed from one end). e.g. Aluminum rod - length=cm- diameter=12mm - holding point center v= m/s (v=velocity K=radius of gyration for cross section L=length) The frequency detected in the experiments for this.

Revision Notes on Waves and Sound Waves Waves: Wave motion: Wave motionis the disturbance, set up in the medium, due to the repeated periodic motion of the particles of the medium and travels from the particle to particle, the particles themselves keep vibrating about their mean positions. Wave Equation: d 2 y/dt 2 = v 2 (d 2 y/dx 2) Transverse wave motion: It is the type of wave motion in. 4 Sound propagation in cylindrical tubes and porous materials having cylindrical pores 45 Introduction 45 Viscosity effects 45 Thermal effects 50 Effective density and bulk modulus for cylindrical tubes having triangular, rectangular and hexagonal cross-sections 54 High- and low-frequency approximation

Monograph on propagation of sound waves in curved ducts After reviewing and evaluating the existing material on sound propagation in curved ducts without flow, it seems strange that, except for Lord Rayleigh in , no book on acoustics has treated the case of wave motion in bends. This monograph reviews the available analytical and experimental material, nearly 30 papers . tion of sound through capillary tubes with mean ﬂow is achieved also by Jeong and Ih (), and ﬁnally an approximate dispersion equation for sound waves in a narrow pipe with ambient gradients is done by Dokumaci (). The problem of a sound wave’s propagation in a stationary ﬂuid or ﬂowing ﬂuid in a porous medium is a new one.

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### Propagation of sound waves in tubes of noncircular cross section Download PDF EPUB FB2

The general Kirchhoff theory of sound propagation in a circular tube is shown to take a considerably simpler form in a regime that includes both narrow and wide tubes.

For tube radii greater than r w =10 −3 cm and sound frequencies f such that r w f 3/2 Cited by: Get this from a library. Propagation of sound waves in tubes of noncircular cross section. [W Bruce Richards; United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch.].

Propagation of sound waves in tubes of noncircular cross section / By W. Bruce. Richards and Lewis Research Center. Topics: Wave-motion, Theory of., Sound-waves., Author: W.

Bruce. Richards and Lewis Research Center. Propagation of sound waves in tubes of noncircular cross section. By W. Richards. Abstract. Plane-acoustic-wave propagation in small tubes with a cross section in the shape of a flattened oval is described.

Theoretical descriptions of a plane wave propagating in a tube with circular cross section and between a pair of infinite parallel Author: W. Richards. endeavors, and extension of the theory to tubes having non- circular cross sections is desirable.

One example is in the study_of sound propagation in porous materials. 6'•4 Pores are rarely circular and, in modeling real materials, micro- structural factors representing the departure from a circular cross section must be introduced. Stinson, M. The propagation of plane sound waves in narrow and wide circular tubes, and generalization to uniform tubes of arbitrary cross-sectional shape.

See also → Sects. J.1, J.2, J.3 for sound propagation in flat or circular capillaries. This second example is not, strictly speaking, an acoustics problem at all (since the thermodynamic processes involved are not isentropic) but relates to wave propagation in narrow tubes, a.

L. Brillouin, “ Propagation of Electric Magnetic Waves in a Tube,” Rev. Gén. de l’Électricité 40, – (). Google Scholar; 5. Of course, there will be other loci in the neighborhoods of circles determined by χρ = a zero of J 1 (x). We are interested only in the locus approximating the original cross section of the tube.

Journal of Sound and Vibration () 39(1), ON THE PROPAGATION OF IN CYLINDRICAL TUBES H. TIJDEMAN National Aerospace Laboratory (NLR), Anthony Fokkerweg 2, Amsterdam, The Netherlands (Received 24 June ) It is shown that the two main parameters governing the propagation of sound waves in.

Sound waves are considered, taking into account the wave equation, the speed of sound, acoustic energy and intensity, the simple source, the acoustic dipole, compact source regions in general, compact source regions with dipole far fields, ripple-tank simulations, scattering by compact bodies, quadrupole radiation, radiation from spheres, radiation from plane walls, and dissipation of acoustic.

Displacements on tube cross-section T of guided waves along an immersed waveguide with arbitrary noncircular cross section. An accurate inverse model is then provided to measure the density of. Stinson, M.R.: The Propagation of Plane Sound Waves in Narrow and Wide Circular Tubes, and Generalization to Uniform Tubes of Arbitrary Cross-Sectional Shape.

Acoust. Soc. Amer. 89, – () CrossRef Google Scholar. See pp. EISENBERG and T. KAO Journal of the Acoustical Society of Amer Propagation of sound through a variable area duct with a steady compressible flow.

MILES Journal of the Acoustical Society of Amer The reflection of sound due to a change in cross section of a circular tube. The propagation of plane sound waves in gases in tubes can be divided into three main types, depending on the radius and frequency involved.

These types are described as `narrow' tube, `wide' tube and `very wide' tube propagation. This book has grown out of the research activities of the author in the fields of sound propagation in porous media and modelling of acoustic materials.

It is assumed that the reader has a background of advanced calculus, including an introduction to differential equations, complex variables and matrix algebra.

A prior exposure to theory of elasticity would be advantageous. Journal of Sound and Vibration () 39(1), ON THE PROPAGATION OF IN CYLINDRICAL TUBES H. TIJDEMAN National Aerospace Laboratory (NLR), Anthony Fokkerweg 2, Amsterdam, The Netherlands (Received 24 June ) It is shown that the two main parameters governing the propagation of sound waves in gases contained in rigid cylindrical tubes, are the shear wave.

Wave propagation and underwater acoustics / edited by Joseph B. Keller and John S. Papadakis; Propagation of sound waves in tubes of noncircular cross section [microform] / W. Bruce Richards; A finite element model for wave propagation in an inhomogeneous [i.e.

inhomogenous] [microform] /. propagation of the wave (sound) can be helpful. When the rod is stroke at the end (exactly like a tube which is closed from one end). For example for a rod described in the table below v= m/s (v=velocity K=radius of gyration for cross section L=length) L m L f.

The propagation of sound waves in tubes of rectangular or circular cross-section is a classic physics problem, and provides the basis for analyzing the tones produced by organ pipes and for calculating room resonant frequencies. We assume the harmonic case with time variation e jωt suppressed.

The wave equation for pressure in this case is. Sound - Sound - Open tubes: In an open tube, the standing wave of the lowest possible frequency for that particular length of tube (in other words, the fundamental) has antinodes at each end and a node in the centre.

This means that an open tube is one-half wavelength long. The fundamental frequency (f1) is thus where Lo is the length of the open tube. 2 Wave equation, speed of sound, and acoustic energy 8 Order of magnitude estimates Smooth change in pipe cross section.

68 Oriﬁce and high amplitude behaviour deﬁnition and to the propagation in ﬂuids like air and water. In such a case acoustics is a part of ﬂuid.where is the cross-sectional area of the tube at point (in square meters), is the longitudinal pressure (in Newtons per square meter), is the density of the fluid in the tube (in kilograms per cubic meter), is the volume velocity of the fluid in the tube (in cubic meters per second), and is the speed of sound in the fluid.

If is assumed to be a constant, then combining the two equations yields.Wave Propagation in a Tube of Constant Cross-Sectional Area. The concatenated tube model is useful because the acoustic behavior of a single tube of constant cross-sectional area is quite simple to describe, in terms of a volume velocity, and a pressure deviation from the mean tube pressure.