scholarly journals Development and Utilization of a Modified Resonator Tube Apparatus for Sound Wave Experiments

2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Alwielland Q. Bello
Keyword(s):  
Speed Of Sound ◽  
Physical Phenomenon ◽  
Normal Modes ◽  
Maximum Amplitude ◽  
Acoustic Resonance ◽  
Resonance Phenomenon ◽  
Harmonic Number ◽  
Sound Waves ◽  
Minimum Amplitude ◽  
Open Pipe

Acoustic resonance is a physical phenomenon in which in-phase sound wavescombine together to produce maximum amplitude; on the other hand, out-of-phasesound waves cancel each other to produce minimum amplitude. The purpose of thisstudy is to investigate and demonstrate this phenomenon with the use of a reliabledevice. This study requires a modified resonator tube apparatus to be developed andfabricated from locally-available materials for the purpose of demonstrating resonanceand normal modes of sound waves. Air column length versus harmonic number (Lvs n) and frequency versus harmonic number (f vs n) experiments were performedtogether with open-pipe and stopped-pipe procedures. For L vs n experiments,deduced value of speed of sound is 337.79±0.94 m/s at 760 Hz for open-pipe takenat 29°C; and 357.72±9.34 m/s at 412 Hz for stopped-pipe taken at 25°C. For f vsn experiments, deduced value of speed of sound is 337.09±5.98 m/s at 2.30 m foropen-pipe taken at 25°C; and 345.92±5.55 m/s at 1.60 m for stopped-pipe takenat 30°C. Results had shown that the modified resonator tube apparatus is accurateand precise within 5% margin of error. Therefore, the apparatus is a reliable devicein demonstrating acoustic resonance phenomenon in the physics classroom setting.Keywords: Physics, Sound Waves, Resonance, Normal Modes, ExperimentalMethod, Philippines

Theory of the rocket-grenade method of measuring temperature, pressure, density and wind velocity in the upper atmosphere

1966 ◽  
Vol 290 (1420) ◽  
pp. 44-73 ◽  
Keyword(s):  
Experimental Data ◽  
Least Squares ◽  
Wind Velocity ◽  
Speed Of Sound ◽  
Vertical Component ◽  
Second Order ◽  
Upper Atmosphere ◽  
Lower Atmosphere ◽  
Travel Times ◽  
Sound Waves

A theory is presented for deriving the speed of sound and wind velocity as a function of height in the upper atmosphere from observations on the travel times of sound waves from accurately located grenades, released during rocket flight, to microphones at surveyed positions on the ground. The theory is taken to a second order of approximation, which can be utilized in practice if lower atmosphere (balloon) measurements are available. By means of the gas law and the vertical equation of motion of the atmosphere, formulae are obtained for deriving temperature, pressure and density from the speed-of-sound profile, and these also may be evaluated to a higher accuracy if lower atmosphere measurements are available. An outline is given of the computational procedure followed in the processing of data on the basis of this theory by means of the Pegasus computer. Methods of calculating the correction to travel times due to the finite wave amplitude are discussed and compared, and the effect of neglecting this correction in a particular set of experimental data is examined. Other errors which may affect the determination of pressure are also discussed. Consistency between the theory and experimental data obtained in 13 Skylark rocket flights at Woomera is checked in two ways: by examining least squares residuals associated with the sound arrivals at various microphones; and by treating the vertical component of air motion as unknown and examining its distribution about zero. The reduction in the least squares residuals which occurs when account is taken of second order terms is evaluated on the basis of these sets of experimental data.

scholarly journals On the acoustic disturbances produced by small bodies in plane waves transmitted through water, with special reference to the single-plate direction finder

1921 ◽  
Vol 100 (704) ◽  
pp. 261-288
Keyword(s):  
Special Reference ◽  
Plane Waves ◽  
Maximum Amplitude ◽  
Sound Waves ◽  
Small Bodies ◽  
Acoustic Disturbances ◽  
Sense Of Direction ◽  
Single Plate ◽  
Direction Finder ◽  
Metal Diaphragm

The experiments to be described were carried out for the Board of Invention and Research, under the direction of Sir William Bragg, between October 1916 and February 1917, on the Cullaloe Reservoir, near Aberdour, Fifeshire, and are now published with the permission of the Admiralty. A form of directional hydrophone has already been described by Sir William Bragg. It consists of a metal diaphragm, A, about four inches in diameter, mounted in a heavy ring, B, and open to the water on both sides ( vide Chart 9). In the centre of the diaphragm is a small metal box, C, carrying a carbon granule microphone of the button type. The microphone is connected into an ordinary telephone circuit. If the instrument is rotated about a vertical diameter in water through which sound waves are passing the sound heard in the receivers passes through a number of maxima and minima. When the diaphragm is turned “edge-on” to the source of sound it is obvious that the pressure pulses will reach the two faces of the diaphragm symmetrically and the diaphragm will fail to vibrate. As, however, either face is turned toward the source this symmetry ceases to exist and the diaphragm is thrown into vibration, which reaches a maximum amplitude when the instrument is “broad-side” on to the source. The instrument, therefore, indicates the line of propagation of the sound, but owing to the existence of two positions of maximum or minimum its indications are ambiguous as regards the sense of direction.

scholarly journals SOUND WAVES IN STRONGLY COUPLED NON-CONFORMAL GAUGE THEORY PLASMA

2005 ◽  
Vol 20 (27) ◽  
pp. 6298-6306 ◽  
Author(s):  
PAOLO BENINCASA
Keyword(s):  
Gauge Theory ◽  
Bulk Viscosity ◽  
Speed Of Sound ◽  
Gauge Theories ◽  
Temperature Limit ◽  
Sound Waves ◽  
Strongly Coupled ◽  
Conformal Theory ◽  
High Temperature Limit ◽  
Conformal Gauge

Gauge/string correspondence provides an efficient method to investigate gauge theories. In this talk we discuss the results of the paper (to appear) by P. Benincasa, A. Buchel and A. O. Starinets, where the propagation of sound waves is studied in a strongly coupled non-conformal gauge theory plasma. In particular, a prediction for the speed of sound as well as for the bulk viscosity is made for the [Formula: see text] gauge theory in the high temperature limit. As expected, the results achieved show a deviation from the speed of sound and the bulk viscosity for a conformal theory. It is pointed out that such results depend on the particular gauge theory considered.

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.

ABSENCE OF A GAP IN THE EXCITATION SPECTRUM (PHONONS) OF ANHARMONIC SOLIDS

1987 ◽  
Vol 01 (01n02) ◽  
pp. 1-5 ◽  
Author(s):  
DANIEL C. MATTIS
Keyword(s):  
Excitation Spectrum ◽  
Speed Of Sound ◽  
Upper Bound ◽  
Ground State ◽  
General Class ◽  
Normal Modes ◽  
Quantum Limit ◽  
Elastic Solids ◽  
Elementary Excitations ◽  
Molecular Solid

Acoustic phonons are the suitably quantized low-lying normal modes of elastic solids. Their energies ε(k) are given by ε(k)=ħω(k), where the frequencies ω(k) are proportional to k (k=wavevector, or inverse wavelength) and vanish as w=sk (s=speed of sound) in the limit k→0. Here we prove a similar result for a reasonably general class of anharmonic solids, applicable even to such solids as the various He4 phases, H2 molecular solid, etc., which are in the extreme quantum limit. We show that the spectrum of elementary excitations in the harmonic solid provides an upper bound to the spectrum of elementary excitations in the similar anharmonic solid having the same ground state interatomic spring constantsK.

The Effect of Upstream Edge Geometry on the Acoustic Resonance Excitation in Shallow Rectangular Cavities

2014 ◽  
Author(s):  
Ahmed Omer ◽  
Nadim Arafa ◽  
Atef Mohany ◽  
Marwan Hassan
Keyword(s):  
Flow Instability ◽  
Acoustic Resonance ◽  
Resonance Mode ◽  
Resonance Phenomenon ◽  
Resonance Excitation ◽  
Base Case ◽  
Pressure Amplitude ◽  
Cavity Depth ◽  
Edge Geometry ◽  
Aspect Ratios

The flow-excited acoustic resonance phenomenon is created when the flow instability oscillations are coupled with one of the acoustic modes, which in turn generates acute noise problems and/or excessive vibrations. In this study, the effect of the upstream edge geometry on attenuating these undesirable effects is investigated experimentally for flows over shallow rectangular cavity with two different aspect ratios of L/D = 1 and 1.67, where L is the cavity length and D is the cavity depth, and for Mach number less than 0.5. The acoustic resonance modes of the cavity are self-excited. Twenty four different upstream cavity edges are investigated in this study; including round edges, chamfered edges, vortex generators and spoilers with different sizes and configurations. The acoustic pressure is measured with a flush-mounted microphone on the cavity floor and the velocity fluctuation of the separated shear layer before the onset of acoustic resonance is measured with a hot-wire probe. The results for each upstream cavity edge are compared with the base case when square cavity edge is used. It is observed that when chamfered edges are used, the amplitude of the first acoustic resonance mode is highly intensified with values reaching around 5000 Pa (compared to 2000 Pa for the base case) and a clear shift in its onset of resonance to higher flow velocities is observed. Similar trend is observed when round edges are used. The amplitude of the generated pressure of the first acoustic resonance mode is amplified with values exceeding 4000 Pa and a delay in its onset of acoustic resonance is observed as well. Most of the spoiler edges are found to be effective in suppressing the pressure amplitude of the excited acoustic resonance. However, the performance of each spoiler depends on its specific geometry (i.e. thickness, height, and angle) relative to the cavity aspect ratio. A summary of the results is presented in this paper.

Closed-Form Solutions to the Exact Optimizations of Dynamic Vibration Absorbers (Minimizations of the Maximum Amplitude Magnification Factors)

2002 ◽  
Vol 124 (4) ◽  
pp. 576-582 ◽  
Author(s):  
Osamu Nishihara ◽  
Toshihiko Asami
Keyword(s):  
Exact Solutions ◽  
Closed Form ◽  
Maximum Amplitude ◽  
Primary System ◽  
Magnification Factor ◽  
Dynamic Vibration Absorber ◽  
Dynamic Vibration ◽  
Classic Problem ◽  
Resonance Frequencies ◽  
Minimum Amplitude

A typical design problem for which the fixed-points method was originally developed is that of minimizing the maximum amplitude magnification factor of a primary system by using a dynamic vibration absorber. This is an example of usual cases for which their exact solutions are not obtained by the well-known heuristic approach. In this paper, more natural formulation of this problem is studied, and algebraic closed-form exact solutions to both the optimum tuning ratio and the optimum damping coefficient for this classic problem are derived under assumption of undamped primary system. It is also proven that the minimum amplitude magnification factor, resonance and anti-resonance frequencies are entirely algebraic.

scholarly journals Determination of the propagation speed of sound waves in propane and LP gas

2020 ◽  
Author(s):  
Niurka Chaveli Castro Chavelas ◽  
Elizabeth Hernandez-Marin ◽  
Gustavo Contreras-Martínez
Keyword(s):  
Speed Of Sound ◽  
Propagation Speed ◽  
Sound Waves

A Parametric Study of the Resonance Mechanism of Two Tandem Cylinders in Cross-Flow

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
A. Mohany ◽  
S. Ziada
Keyword(s):  
Parametric Study ◽  
Small Diameter ◽  
Cross Flow ◽  
Acoustic Resonance ◽  
Acoustic Mode ◽  
Resonance Phenomenon ◽  
Resonance Mechanism ◽  
Flow Parameters ◽  
Tandem Cylinders ◽  
Spacing Ratio

A parametric study has been performed to investigate the effect of cylinder diameter on the acoustic resonance mechanism of two tandem cylinders exposed to cross-flow in a duct. Three spacing ratios corresponding to different flow regimes inside the “proximity interference” region are considered, L∕D=1.5, 1.75, and 2.5, where L is the spacing between the cylinders and D is the diameter. For each spacing ratio, six cylinder diameters in the range of D=7.6–27.5mm have been tested. For small diameter cylinders, the acoustic resonance mechanism of the tandem cylinders seems to be similar to that observed for single cylinders; i.e., it occurs near frequency coincidence as the vortex shedding frequency approaches that of an acoustic resonance mode. However, for larger diameter cylinders, the resonance of a given acoustic mode occurs over two different ranges of flow velocity. The first resonance range, the precoincidence resonance, occurs at flow velocities much lower than that of frequency coincidence. The second resonance range, the coincidence resonance, is similar to that observed for single and small diameter tandem cylinders. Interestingly, the observed precoincidence resonance phenomenon is similar to the acoustic resonance mechanism of in-line tube bundles. It is shown that increasing the diameter of the tandem cylinders affects several flow parameters such that the system becomes more susceptible to the precoincidence resonance phenomenon. The occurrence and the intensity of the precoincidence resonance are therefore strongly dependent on the diameter of the cylinders.

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