scholarly journals Acoustic coupling between pistons in a rigid baffle

2009 ◽  
Vol 126 (5) ◽  
pp. EL166-EL169
Author(s):  
Kassiani Kotsidou ◽  
Charles Thompson
Keyword(s):  
Acoustic Coupling ◽  
Rigid Baffle

Investigation of zirconium nanowire by elastic, thermal and ultrasonic analysis

2020 ◽  
Vol 75 (12) ◽  
pp. 1077-1084
Author(s):  
Bhawan Jyoti ◽  
Shakti Pratap Singh ◽  
Mohit Gupta ◽  
Sudhanshu Tripathi ◽  
Devraj Singh ◽  
...  
Keyword(s):  
Ultrasonic Attenuation ◽  
Thermal Relaxation ◽  
Coupling Constants ◽  
Physical Parameters ◽  
Third Order ◽  
Jones Potential ◽  
Acoustic Coupling ◽  
Anisotropic Factor ◽  
Third Order Elastic Constants ◽  
Ultrasonic Analysis

AbstractThe elastic, thermal and ultrasonic properties of zirconium nanowire (Zr-NW) have been investigated at room temperature. The second and third order elastic constants (SOECs and TOECs) of Zr-NW have been figured out using the Lennard–Jones Potential model. SOECs have been used to find out the Young’s modulus, bulk modulus, shear modulus, Poisson’s ratio, Pugh’s ratio, Zener anisotropic factor and ultrasonic velocities. Further these associated parameters of Zr-NW have been utilized for the evaluation of the Grüneisen parameters, thermal conductivity, thermal relaxation time, acoustic coupling constants and ultrasonic attenuation. On the basis of the above analyzed properties of Zr-NW, some characteristics features of the chosen nanowire connected with ultrasonic and thermo-physical parameters have been discussed.

Pressure dependent ultrasonic properties of hcp hafnium metal

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ramanshu P. Singh ◽  
Shakti Yadav ◽  
Giridhar Mishra ◽  
Devraj Singh
Keyword(s):  
Elastic Constants ◽  
Pressure Range ◽  
Room Temperature ◽  
Ultrasonic Attenuation ◽  
Coupling Constants ◽  
Ultrasonic Properties ◽  
Acoustic Coupling ◽  
Third Order Elastic Constants ◽  
The Stability ◽  
The Given

Abstract The elastic and ultrasonic properties have been evaluated at room temperature between the pressure 0.6 and 10.4 GPa for hexagonal closed packed (hcp) hafnium (Hf) metal. The Lennard-Jones potential model has been used to compute the second and third order elastic constants for Hf. The elastic constants have been utilized to calculate the mechanical constants such as Young’s modulus, bulk modulus, shear modulus, Poisson’s ratio, and Zener anisotropy factor for finding the stability and durability of hcp hafnium metal within the chosen pressure range. The second order elastic constants were also used to compute the ultrasonic velocities along unique axis at different angles for the given pressure range. Further thermophysical properties such as specific heat per unit volume and energy density have been estimated at different pressures. Additionally, ultrasonic Grüneisen parameters and acoustic coupling constants have been found out at room temperature. Finally, the ultrasonic attenuation due to phonon–phonon interaction and thermoelastic mechanisms has been investigated for the chosen hafnium metal. The obtained results have been discussed in correlation with available findings for similar types of hcp metals.

Aero-Acoustic Coupling Inside Large Deep Cavities at Low-Subsonic Speeds

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Mouhammad El Hassan ◽  
Laurent Keirsbulck ◽  
Larbi Labraga
Keyword(s):  
Wind Tunnel ◽  
Shear Layer ◽  
Convection Velocity ◽  
Pressure Amplitude ◽  
Hydrodynamic Mode ◽  
Freestream Velocity ◽  
Acoustic Coupling ◽  
Deep Cavity ◽  
Cross Correlations ◽  
Deep Cavities

Aero-acoustic coupling inside a deep cavity is present in many industrial processes. This investigation focuses on the pressure amplitude response, within two deep cavities characterized by their length over depth ratios (L/H=0.2 and 0.41), as a function of freestream velocities of a 2×2m2 wind tunnel. Convection velocity of instabilities was measured along the shear layer, using velocity cross-correlations. Experiments have shown that in deep cavity for low Mach numbers, oscillations of discrete frequencies can be produced. These oscillations appear when the freestream velocity becomes higher than a minimum value. Oscillations start at L/θ0=10 and 21 for L/H=0.2 and 0.41, respectively. The highest sound pressure level inside a deep cavity is localized at the cavity floor. A quite different behavior of the convection velocity was observed between oscillating and nonoscillating shear-layer modes. The hydrodynamic mode of the cavity shear layer is well predicted by the Rossiter model (1964, “Wind Tunnel Experiments on the Flow Over Rectangular Cavities at Subsonic and Transonic Speeds,” Aeronautical Research Council Reports and Memo No. 3438) when measured convection velocity is used and the empirical time delay is neglected. For L/H=0.2, only the first Rossiter mode is present. For L/H=0.41, both the first and the second modes are detected with the second mode being the strongest.

Acoustic coupling free electric drum

1983 ◽  
Vol 73 (2) ◽  
pp. 719-719
Author(s):  
Robert D. Scott
Keyword(s):  
Acoustic Coupling
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