Comparison of Theory and Experiment for Forced Sound‐Wave Propagation in Rarefied Gasdynamics: Reply to “Comments on ‘Propagation of Forced Sound Waves in Rarefied Gasdynamics’” [G. Maidanik and H. L. Fox, J. Acoust. Soc. Am. 38, 477–478(L) (1965)]

1965 ◽  
Vol 38 (3) ◽  
pp. 478-480 ◽  
Author(s):  
Lawrence Sirovich ◽  
James K. Thurber
Keyword(s):  
Wave Propagation ◽  
Sound Wave ◽  
Sound Waves ◽  
Theory And Experiment

Paper 11: Variation of Hydraulic Pressure in Annular Space between Guide Vanes and Impeller of a Francis Turbine

1966 ◽  
Vol 181 (1) ◽  
pp. 109-118
Author(s):  
E. Lund
Keyword(s):  
Wave Propagation ◽  
Sound Wave ◽  
Pressure Wave ◽  
Resonance Phenomenon ◽  
Francis Turbine ◽  
Laboratory Model ◽  
Hydraulic Pressure ◽  
Sound Waves ◽  
Annular Space ◽  
Guide Vanes

One of the main sources of vibration in Francis turbines is thought to be pressure-wave disturbances generated from the impeller and interference impulses between impeller vanes and guide vanes. A theory is developed which explains the occurrence of severe vibrations caused by the elasticity of the water as a resonance phenomenon between the disturbing impulses and normal modes of vibration in the space between the impeller and the guide wheel. The wave propagation in the fluid, which is assumed to be uniform with no steady flow, is thought to satisfy the well-known sound-wave differential equation without any damping effects. The natural frequencies for one- and two-dimensional pressure-wave oscillations are calculated. The calculations, based on prior knowledge of the velocity of sound-wave propagation, show that a simple theory of one-dimensional oscillations interpreted as rotating sound waves in the annular space is sufficient to predict critical speeds of the turbine. Measurements carried out on a laboratory model Francis turbine for a head of 4.5 m and a capacity of about 1.0 m3/s confirmed the presence of free oscillations and indicated the occurrence of a resonance phenomenon in the annular space.

Simulation of Sound Wave Propagation With Damping for Realistic Sound rendering for Games and Interactive Applications

2012 ◽  
Author(s):  
Bruno Moreira ◽  
Mauricio Kischinhevsky ◽  
Marcelo Zamith ◽  
Esteban Clua ◽  
Diego Brandao
Keyword(s):  
Wave Propagation ◽  
Sound Wave ◽  
Interactive Applications ◽  
Sound Rendering

Interaction between Strong Sound Waves and Cloud Droplets: Theoretical Analysis

2021 ◽  
Author(s):  
Ying-Hui Jia ◽  
Fang-Fang Li ◽  
Kun Fang ◽  
Guang-Qian Wang ◽  
Jun Qiu
Keyword(s):  
Sound Wave ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Sound Field ◽  
Pressure Level ◽  
Velocity Variation ◽  
Time Range ◽  
Sound Waves ◽  
Cloud Droplets ◽  
Acoustic Frequency

AbstractRecently strong sound wave was proposed to enhance precipitation. The theoretical basis of this proposal has not been effectively studied either experimentally or theoretically. Based on the microscopic parameters of atmospheric cloud physics, this paper solved the complex nonlinear differential equation to show the movement characteristics of cloud droplets under the action of sound waves. The motion process of individual cloud droplet in a cloud layer in the acoustic field is discussed as well as the relative motion between two cloud droplets. The effects of different particle sizes and sound field characteristics on particle motion and collision are studied to analyze the dynamic effects of thunder-level sound waves on cloud droplets. The amplitude of velocity variation has positive correlation with Sound Pressure Level (SPL) and negative correlation with the frequency of the surrounding sound field. Under the action of low-frequency sound waves with sufficient intensity, individual cloud droplets could be forced to oscillate significantly. The droplet smaller than 40μm can be easily driven by sound waves of 50 Hz and 123.4 dB. The calculation of the collision process of two droplets reveals that the disorder of motion for polydisperse droplets is intensified, resulting in the broadening of the collision time range and spatial range. When the acoustic frequency is less than 100Hz (@ 123.4dB) or the Sound Pressure Level (SPL) is greater than 117.4dB (@ 50Hz), the sound wave can affect the collision of cloud droplets significantly. This study provides theoretical perspective of acoustic effect to the microphysics of atmospheric clouds.

scholarly journals Spiral Sound Wave Transducer Based on the Longitudinal Vibration

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3674 ◽  
Author(s):  
Wei Lu ◽  
Yu Lan ◽  
Rongzhen Guo ◽  
Qicheng Zhang ◽  
Shichang Li ◽  
...  
Keyword(s):  
Sound Wave ◽  
Longitudinal Vibration ◽  
Three Dimensional ◽  
Low Frequency ◽  
Sound Field ◽  
Field Measurements ◽  
Sound Waves ◽  
Underwater Sound ◽  
Three Dimensional Finite Element ◽  
Wave Transducer

A spiral sound wave transducer comprised of longitudinal vibrating elements has been proposed. This transducer was made from eight uniform radial distributed longitudinal vibrating elements, which could effectively generate low frequency underwater acoustic spiral waves. We discuss the production theory of spiral sound waves, which could be synthesized by two orthogonal acoustic dipoles with a phase difference of 90 degrees. The excitation voltage distribution of the transducer for emitting a spiral sound wave and the measurement method for the transducer is given. Three-dimensional finite element modeling (FEM)of the transducer was established for simulating the vibration modes and the acoustic characteristics of the transducers. Further, we fabricated a spiral sound wave transducer based on our design and simulations. It was found that the resonance frequency of the transducer was 10.8 kHz and that the transmitting voltage resonance was 140.5 dB. The underwater sound field measurements demonstrate that our designed transducer based on the longitudinal elements could successfully generate spiral sound waves.

Sound-wave propagation in a rarefied gas

1979 ◽  
Vol 8 (4) ◽  
pp. 219-240 ◽  
Author(s):  
J. R. Thomas ◽  
C. E. Siewert
Keyword(s):  
Wave Propagation ◽  
Sound Wave ◽  
Rarefied Gas

Finite‐Amplitude Sound‐Wave Propagation in a Waveguide

1971 ◽  
Vol 49 (1B) ◽  
pp. 329-333 ◽  
Author(s):  
Joseph B. Keller ◽  
Martin H. Millman
Keyword(s):  
Wave Propagation ◽  
Sound Wave ◽  
Finite Amplitude

scholarly journals Dredge-up by Sound Wave Emission from a Convective Core

1988 ◽  
Vol 108 ◽  
pp. 99-100
Author(s):  
Masa-aki Kondo
Keyword(s):  
Spherical Harmonics ◽  
Sound Wave ◽  
Sound Waves ◽  
Bottom Boundary ◽  
Ob Stars ◽  
Nonradial Oscillation ◽  
Convective Core ◽  
Propagation Zone ◽  
Wave Emission ◽  
Upper Boundary

Concerning the scattering of OB stars in the HR diagram (Humphry 1980), the effects of overshooting of convective core (Maeder 1984), mass loss (cf. chiosi and Maeder 1986), and generous stability criterion of semi-convection (Stothers and Chin 1976) have been discussed. Here, we will note the dredge up effect is caused by the sound waves emitted from a convective core.The sound mode of nonradial oscillation, with the spherical harmonics Ylm(θ, ϕ) and the frequency ω, can exist in the propagation zone, where the bottom boundary locates at the position of , and the upper boundary does near the photosphere. Here, Ll is called as the Lamb frequency, and cs is the sound velocity.

scholarly journals Feasibility of Physics Teaching Materials With Qur'an Using Generative Learning Model on Sound Waves

2021 ◽  
Vol 9 (3) ◽  
pp. 305
Author(s):  
Muhammad Lutfi ◽  
Zainuddin Zainuddin ◽  
Eko Susilowati
Keyword(s):  
Learning Outcomes ◽  
Sound Wave ◽  
Lesson Plan ◽  
Generative Learning ◽  
Sound Waves ◽  
Teaching Materials ◽  
Physics Teaching ◽  
Plan Implementation ◽  
A Value ◽  
Addie Model

Preliminary observations show the limitations of teaching materials that have a relationship with spiritual aspects, especially the Qur'an, which is due to the limitations of teaching materials that contain these aspects. Required learning that stimulates students to generalize religious aspects and learn physics. Therefore, the purpose of this study is to describe the feasibility of physics teaching materials containing the Qur'an by using a generative model on sound wave material. This study aims to describe the validity, practicality, and effectiveness of the teaching materials developed. The research was conducted on 33 students at class XI MIPA 1 MAN 2 Model Banjarmasin using the ADDIE model. Data was taken from the validation results of teaching materials using validation sheet, lesson plan implementation using lesson plan implementation sheet, and students' learning outcomes at the pretest and post-test using learning outcomes tests. The results of this study were 1) the validity of the teaching materials was in the "valid" category with a value of 3.33, 2) the practicality of the teaching materials was in the "very practical" category with a value of 3.63, and 3) the effectiveness of the teaching material was in the "effective/moderate" category with a value of 0,44. This study concluded that physics teaching materials containing Al-Qur'an verses on sound wave materials using generative learning models are declared feasible to be used based on the validity, practicality, and effectiveness of the teaching materials. The implication of this research is the creation of teaching materials containing the Qur'an that are used in schools and creating student habits to link physics and the Qur'an.

Sound Propagation in Dilute Polyatomic Gases

1972 ◽  
Vol 27 (4) ◽  
pp. 583-592
Author(s):  
H. Moraal ◽  
F. Mccourt
Keyword(s):  
Pressure Range ◽  
Sound Propagation ◽  
Plane Waves ◽  
Point Of View ◽  
Perturbation Function ◽  
Sound Waves ◽  
Polyatomic Gas ◽  
Measured Pressure ◽  
Theory And Experiment ◽  
Good Agreement

Abstract Sound propagation in dilute pure gases, both monatomic and polyatomic, has been considered from the point of view of the Waldmann-Snider equation. It is shown that the commonly employed assumption that sound propagation in gases is equivalent to the propagation of plane waves is valid only in the region where collisions restore equilibrium faster than it is perturbed by the sound waves. A systematic truncation procedure for an expansion of the perturbation function in irreducible Cartesian tensors is introduced and then illustrated in solutions for three specific kinds of molecules, helium, nitrogen and rough spheres. The agreement between theory and experiment is rather good for sound absorption in the region where the ratio of the collision and sound frequencies is greater than 1.5. The agreement in the case of dispersion is good over the whole measured pressure range. One useful result obtained is to show the polyatomic gas calculations in second approximation have as good agreement with experiment as the calculations for noble gases in third approximation. This can be related to the possession by the polyatomic gas of a bulk viscosity which dominates in sound propagation.

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