A comparison of high frequency acoustic transmission data from a smooth water/sand interface with a composite poroelastic model

2002 ◽  
Vol 112 (5) ◽  
pp. 2254-2254
Author(s):  
Marcia Isakson ◽  
Daniel Weigl ◽  
Erik Bigelow ◽  
Nicholas Chotiros
Keyword(s):  
High Frequency ◽  
Acoustic Transmission ◽  
Transmission Data ◽  
Poroelastic Model

Prediction of High Frequency Sonic Boom Noise Transmission Into Buildings Using a Hybrid Analytical-Ray Tracing Approach

2012 ◽  
Author(s):  
Joseph M. Corcoran ◽  
Marcel C. Remillieux ◽  
Ricardo A. Burdisso
Keyword(s):  
Ray Tracing ◽  
High Frequency ◽  
Acoustic Radiation ◽  
Low Frequency ◽  
Sonic Boom ◽  
Acoustic Transmission ◽  
Frequency Method ◽  
Low Frequencies ◽  
Sonic Booms ◽  
Acoustic Responses

As part of the effort to renew commercial supersonic flight, a predictive numerical tool to compute sonic boom transmission into buildings is under development. Due to the computational limitations of typical numerical methods used at low frequencies (e.g. Finite Element Method), it is necessary to develop a separate approach for the calculation of acoustic transmission and interior radiation at high frequencies. The high frequency approach can then later be combined with a low frequency method to obtain full frequency vibro-acoustic responses of buildings. An analytical method used for the computation of high frequency acoustic transmission through typical building partitions is presented in this paper. Each partition is taken in isolation and assumed to be infinite in dimension. Using the fact that a sonic boom generated far from the structure will approximate plane wave incidence, efficient analytical solutions for the vibration and acoustic radiation of different types of partitions are developed. This is linked to a commercial ray tracing code to compute the high frequency interior acoustic response and for auralization of transmitted sonic booms. Acoustic and vibration results of this high frequency tool are compared to experimental data for a few example cases demonstrating its efficiency and accuracy.

Dynamics of hydraulic fracture development according to acoustic transmission data

2021 ◽  
Author(s):  
Sergey Turuntaev ◽  
Evgeny Zenchenko ◽  
Petr Zenchenko ◽  
Maria Trimonova ◽  
Nikolai Baryshnikov
Keyword(s):  
Hydraulic Fracturing ◽  
Hydraulic Fracture ◽  
Injection Pressure ◽  
Ultrasonic Pulse ◽  
Theoretical Research ◽  
Fracture Rate ◽  
Acoustic Transmission ◽  
Fracturing Fluid ◽  
Fracture Closure ◽  
Transmission Data

<p>Acoustic transmission data obtained in laboratory experiment were used to estimate main stages of hydraulic fracture onset, growth and filling by fracturing fluid. Laboratory setup consists of two horizontal disks with a diameter of 750 mm, and a sidewall with an internal diameter of 430 mm. The disks and the sidewall form a pressure chamber with a diameter of 430 mm at a height of 70 mm. There are a number of holes in the disks and the sidewall that are used for mounting ultrasonic transducers, pressure sensors, as well as for fluid injections. As a model material, a mixture of gypsum with cement was used, which was poured into the chamber. The sample was saturated with water gypsum solution and loaded with vertical and two horizontal stresses using special chambers. The fracture was created by viscous fluid (mineral oil with viscosity 0.1 Pa*s) injection with a constant rate 0.2 cm<sup>3</sup>/s through a cased borehole (diameter 12 mm) with a horizontal slot, which was preliminary located in the center of the sample. Hydraulic fracturing monitoring was carried out by recording of ultrasonic pulses passing through the sample during fracturing. To separate the ultrasonic pulses, the frequency of their sending was used. After that, the envelope of each record fragment was constructed using the Hilbert transformation and its maximum was found. Comparison of the ultrasonic pulse amplitude variations and injection pressure led to the following observations. Initial decrease in the pulse amplitudes began before the maximum pressure was reached, which may indicate the hydraulic fracturing onset at a pressure less than the maximum. The amplitude decline occurs smoothly, so it is difficult to identify any characteristic point on these curves and, accordingly, it is difficult to establish an accurate time of the fracturing onset and the fracture rate. The fracture rate was estimated by different methods previously as ≈130 mm/s. After the decline, the pulse amplitudes started to increase, that was related with the injection fluid front propagation in the fracture. In contrast to the decline, the beginning of the amplitude growth was clearly detected. Taking into account the spatial locations of the ultrasonic pulse source, receivers, and fracture, it is possible to estimate the propagation velocity of the fracturing fluid front as ≈35 mm/s. After the increase, the ultrasonic pulse amplitudes started to decrease significantly (up to 3 times), which is probably due to the further expansion of the fracture aperture. On the transducers located closer to the well, this decline is maximum. When the injection is stopped, the ultrasonic pulse amplitudes began to grow again, which indicates the fracture closure as the injection pressure decrease. In the experiments on the fracture re-opening under various stress applied to the sample, a linear relationship between the fracture re-opening pressure and applied vertical stress was found. This type of relationship should be expected, but values of the relation parameters declined from the values suggested in theoretical research, which was explained by taken into account back-stresses and non-linear behavior of the sample material.</p>

An Improved Compressive Sensing Image Fusion Algorithm Based on NSCT Transform

2013 ◽  
Vol 433-435 ◽  
pp. 306-309 ◽  
Author(s):  
Yan Hai Wu ◽  
Di Yan ◽  
Meng Xin Ma ◽  
Nan Wu
Keyword(s):  
Image Fusion ◽  
Compressive Sensing ◽  
High Frequency ◽  
Low Frequency ◽  
Objective Evaluation ◽  
Fusion Image ◽  
Fusion Algorithm ◽  
Absolute Value ◽  
Transmission Data ◽  
Improved Algorithm

A modified compressive sensing image fusion algorithm is proposed in this paper that is based on the NSCT transform. The algorithm is improved by introducing the theory of compressive sensing into image fusion that uses the NSCT transform to make a specific image be sparse on which only the high frequency coefficient is specifically measured; The improved algorithm then process the image fusion by retrieving the maximal value of the gradient of the neighborhood average from the measured high frequency coefficient, and accordingly, maximizing the absolute value of the neighborhood variance to the low-frequency counterpart. Afterwards, the improved algorithm can reconfigure the fusion image by using the MSP reconfiguration algorithm with final deliverable of the fusion image by committing to the NSCT reverse transform. Simulation results show that the improved algorithm is superior to other hand-on algorithms both in visual effect and in objective evaluation. In the case that the storage and transmission data are limited, the algorithm comes forth better effect of image fusion that is verified to be possesses of high value in practice.

Measurements of high frequency acoustic transmission loss during SAVEX15

2016 ◽  
Vol 140 (4) ◽  
pp. 3065-3065 ◽  
Author(s):  
Su-Uk Son ◽  
Jee Woong Choi ◽  
Seung Woo Lee ◽  
SungHyun Nam ◽  
Sungho Cho
Keyword(s):  
High Frequency ◽  
Transmission Loss ◽  
Acoustic Transmission
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