The three‐dimensional acoustic field of primary arrivals from a seismic airgun array.

2010 ◽  
Vol 127 (3) ◽  
pp. 1787-1787
Author(s):  
Arslan M. Tashmukhambetov ◽  
George E. Ioup ◽  
Juliette W. Ioup ◽  
Natalia A. Sidorovskaia ◽  
Anca Niculescu ◽  
...  
2021 ◽  
Vol 143 (10) ◽  
Author(s):  
Ketki M. Lichade ◽  
Yayue Pan

Abstract This study successfully integrates acoustic patterning with the Two-Photon Polymerization (TPP) process for printing nanoparticle–polymer composite microstructures with spatially varied nanoparticle compositions. Currently, the TPP process is gaining increasing attention within the engineering community for the direct manufacturing of complex three-dimensional (3D) microstructures. Yet the full potential of TPP manufactured microstructures is limited by the materials used. This study aims to create and demonstrate a novel acoustic field-assisted TPP (A-TPP) process, which can instantaneously pattern and assemble nanoparticles in a liquid droplet, and fabricate anisotropic nanoparticle–polymer composites with spatially controlled particle–polymer material compositions. It was found that the biggest challenge in integrating acoustic particle patterning with the TPP process is that nanoparticles move upon laser irradiation due to the photothermal effect, and hence, the acoustic assembly is distorted during the photopolymerization process. To cure acoustic assembly of nanoparticles in the resin through TPP with the desired nanoparticle patterns, the laser power needs to be carefully tuned so that it is adequate for curing while low enough to prevent the photothermal effect. To address this challenge, this study investigated the threshold laser power for polymerization of TPP resin (Pthr) and photothermal instability of the nanoparticle (Pthp). Patterned nanoparticle–polymer composite microstructures were fabricated using the novel A-TPP process. Experimental results validated the feasibility of the developed acoustic field-assisted TPP process on printing anisotropic composites with spatially controlled material compositions.


2017 ◽  
Author(s):  
Goutam Ghoshal ◽  
Kedar C. Chitale ◽  
Benjamin P. Ross-Johnsrud ◽  
Yurii A. Ilinskii ◽  
Evgenia A. Zabolotskaya ◽  
...  

Author(s):  
Dongdong Liu ◽  
Yanyan Chen ◽  
Wei Dai ◽  
Ercang Luo

Abstract As a new type of acoustic-electric conversion method, bi-directional impulse turbine provides great potential for developing large scale and economic thermoacoustic power generators. A test rig for turbine tests in acoustic fields, which are provided through two reciprocating pistons, has been introduced. A three-dimensional numerical model has been used to simulate the whole system. The fundamental characteristics of the turbine in oscillating flow are analyzed. Impact of acoustic field features on the turbine performance has been studied. The results show that the performance is sensitive to the acoustic field. For the test rig, a typical result is that with a shaft power of 187 W, the turbine can reach an efficiency around 32%.


Author(s):  
Nail A. Gumerov ◽  
Iskander S. Akhatov ◽  
Claus-Dieter Ohl ◽  
Sergei P. Sametov ◽  
Maxim V. Khasimulin ◽  
...  

Self-organization of bubbles in acoustic fields, or self-action of the acoustic waves in bubbly liquids is a strongly nonlinear phenomenon due to two-way interaction of the bubbles and the acoustic field. Theoretical model and preliminary computations predict that waves of self-induced acoustic transparency may exist. Such effect is confirmed in the experiments presented in this paper. Formation of a wave of void fraction which rapidly propagates through the bubbly medium leaving a region almost free of bubbles behind its front is observed in the experiments. Measurements of the dynamics of such a wave at different acoustic frequencies and amplitudes are carried out. A three dimensional model of self-organization of a polydisperse bubble continuum in acoustic field is developed and the results of simulations are compared with experiments. A good agreement of the theory and experiment is found.


2013 ◽  
Vol 134 (5) ◽  
pp. 4113-4113
Author(s):  
Arslan M. Tashmukhambetov ◽  
George E. Ioup ◽  
Juliette W. Ioup ◽  
Natalia A. Sidorovskaia ◽  
Joal J. Newcomb ◽  
...  

2019 ◽  
Vol 874 ◽  
Author(s):  
Erik Lindborg

We consider a three-dimensional acoustic field of an ideal gas in which all entropy production is confined to weak shocks and show that similar scaling relations hold for such a field as for forced Burgers turbulence, where the shock amplitude scales as $(\unicode[STIX]{x1D716}d)^{1/3}$ and the $p$th-order structure function scales as $(\unicode[STIX]{x1D716}d)^{p/3}r/d$, $\unicode[STIX]{x1D716}$ being the mean energy dissipation per unit mass, $d$ the mean distance between the shocks and $r$ the separation distance. However, for the acoustic field, $\unicode[STIX]{x1D716}$ should be replaced by $\unicode[STIX]{x1D716}+\unicode[STIX]{x1D712}$, where $\unicode[STIX]{x1D712}$ is associated with entropy production due to heat conduction. In particular, the third-order longitudinal structure function scales as $\langle \unicode[STIX]{x1D6FF}u_{r}^{3}\rangle =-C(\unicode[STIX]{x1D716}+\unicode[STIX]{x1D712})r$, where $C$ takes the value $12/5(\unicode[STIX]{x1D6FE}+1)$ in the weak shock limit, $\unicode[STIX]{x1D6FE}=c_{p}/c_{v}$ being the ratio between the specific heats at constant pressure and constant volume.


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