Simulation of multiwavelength conditions in laser picosecond ultrasonics

SIMULATION ◽  
2021 ◽  
pp. 003754972199645
Author(s):  
Philippe Babilotte
Keyword(s):  
Numerical Simulations ◽  
Acoustic Signal ◽  
Acoustic Waves ◽  
Bulk Material ◽  
Deformation Field ◽  
Optical Pump ◽  
Pump And Probe ◽  
Oriented Object ◽  
Numerical Approaches ◽  
Picosecond Ultrasonics

Complete numerical simulations are given under SciLab® and MATLAB® coding environments, concerning propagative acoustic wavefronts, for laser picosecond ultrasonics under multiwavelength conditions. Simulations of the deformation field and its propagation into bulk material are given under different wavelength configurations for optical pump and probe beams, which are used to generate and to detect the acoustic signal. Complete insights concerning the dynamics of the acoustic waves are given, considering the absence of carrier diffusions into the material. Several numerical approaches are proposed concerning both the functions introduced to simulate the wavefront ( Heaviside or error) and the coding approach (linear/vectorized/ Oriented Object Programming), under the pure thermo-elastic approach.

Microcontroller Device for Conductor Identification Using Acoustic Signal

2020 ◽  
Vol 67 (1) ◽  
pp. 28-34
Author(s):  
Aleksandr V. Vinogradov ◽  
Aleksey V. Bukreev
Keyword(s):  
Acoustic Signal ◽  
Acoustic Waves ◽  
Theoretical Calculations ◽  
Poor Quality ◽  
Electrical Circuit ◽  
Research Purpose ◽  
Electrical Wiring ◽  
The Right ◽  
The Cost ◽  
Technical Solutions

When repairing and replacing electrical wiring in enterprises, the main difficulty is the lack or poor quality of documentation, plans for conductors laying. Distinguishing wires (cables) and their cores by the color of the shells or using tags attached to the ends is difficult if the shells have the same color and there are no tags. Devices and technical solutions used to identify wires and cables do not allow recognizing conductors without breaking the electrical circuit, removing insulation, and de-energizing the network. Searching for the right conductor is a time-consuming operation. (Research purpose) The research purpose is developing a new microcontroller device for identifying wires using an acoustic signal. (Materials and methods) Literature sources has been searched for devices for conductors identifying. (Results and discussion) The article proposes a method that involves feeding an acoustic signal to a wire at one point and capturing it at another, in order to recognize the desired wire. The article presents results of comparison of the developed microcontroller device for identifying conductors using an acoustic signal with known devices and methods for conductors recognizing. (Conclusions) The article reveals the shortcomings of existing methods and means of identifying wires and cables. Authors performed a theoretical calculation of the sound pressure in the conductor at a given distance. The article presents the calculation of speed of acoustic waves in conductors with different types of insulation. Authors designed a microcontroller device for identifying conductors using an acoustic signal and tested it. It was determined that the device increases the safety of work, reduces the cost of operating internal wiring and identification time; eliminates the violation of wire insulation, the need to disable electrical receivers. The convergence of theoretical calculations and experimental data was shown.

Optical pump-and-probe measurement of the thermal conductivity of nitride thin films

2002 ◽  
Vol 92 (7) ◽  
pp. 3820-3824 ◽  
Author(s):  
B. C. Daly ◽  
H. J. Maris ◽  
A. V. Nurmikko ◽  
M. Kuball ◽  
J. Han
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Probe Measurement ◽  
Optical Pump ◽  
Pump And Probe

A weakly nonlinear framework to study shock–vorticity interaction

2022 ◽  
Vol 933 ◽  
Author(s):  
Pranav Thakare ◽  
Vineeth Nair ◽  
Krishnendu Sinha
Keyword(s):  
Numerical Simulations ◽  
Acoustic Waves ◽  
Significant Contribution ◽  
Interaction Analysis ◽  
Nonlinear Effects ◽  
Normal Shock ◽  
Linear Interaction ◽  
Weakly Nonlinear ◽  
High Incidence ◽  
Vorticity Generation

Linear interaction analysis (LIA) is routinely used to study the shock–turbulence interaction in supersonic and hypersonic flows. It is based on the inviscid interaction of elementary Kovásznay modes with a shock discontinuity. LIA neglects nonlinear effects, and hence it is limited to small-amplitude disturbances. In this work, we extend the LIA framework to study the fundamental interaction of a two-dimensional vorticity wave with a normal shock. The predictions from a weakly nonlinear framework are compared with high-order accurate numerical simulations over a range of wave amplitudes ( $\epsilon$ ), incidence angles ( $\alpha$ ) and shock-upstream Mach numbers ( $M_1$ ). It is found that the nonlinear generation of vorticity at the shock has a significant contribution from the intermodal interaction between vorticity and acoustic waves. Vorticity generation is also strongly influenced by the curvature of the normal shock wave, especially for high incidence angles. Further, the weakly nonlinear analysis is able to predict the correct scaling of the nonlinear effects observed in the numerical simulations. The analysis also predicts a Mach number dependent limit for the validity of LIA in terms of the maximum possible amplitude of the upstream vorticity wave.

Basin Tests and Numerical Simulations of Wake-Induced Oscillations of In-Line Risers in Subcritical/Critical Regime

2018 ◽  
Author(s):  
Vincent Levasseur ◽  
Charles Leca ◽  
Benjamin Rousse ◽  
Francois Pétrié
Keyword(s):  
Numerical Simulations ◽  
Industrial Design ◽  
Design Tool ◽  
Critical Regime ◽  
Incoming Flow ◽  
Numerical Approaches

This paper adresses Wake Induced Oscillations in the transition between subcritical and critical regime. Both experimental and numerical approaches are proposed and compared here to model tandem risers motion. The main purpose is to enlarge our insights of the behavior of different arrangements of risers in this very tricky range of incoming flow (Re ∈ [134,000; 300,000]) and to assess the CFD ability as an industrial design tool.

Anomaly of Thermal Properties in Thin Films of La1-x SrxCoO3 Series Fabricated as Thermoelectric Materials

2002 ◽  
Vol 730 ◽  
Author(s):  
Yoshiaki Takata ◽  
Hajime Haneda ◽  
Yutaka Adachi ◽  
Yoshiki Wada ◽  
Takefumi Mitsuhashi ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Thermoelectric Materials ◽  
Signal Analysis ◽  
Material Synthesis ◽  
Thermo Electric ◽  
Optical Pump ◽  
Pump And Probe ◽  
Reflection Geometry

AbstractComposition spreads of La1-xSrxCoO3 (LSCO) were synthesized as thermo-electric transducer material by means of combinatorial material synthesis, and information on their thermal diffusivity throughout the specimens was obtained. Meanwhile, it is anticipated that the composition spreads of LSCO have a variety of characteristic properties of light absorption corresponding to their composition, namely their compositional variable, x. Hence, we used transient optical pump-and-probe techniques in a reflection geometry to measure thermal diffusion times on LSCO. The results of signal analysis indicate that LSCO is a peculiar synthesized substance whose apparent thermal diffusivity, 1/ι, changes abruptly at the critical point, where the compositional variable x is equal to 0.3.

scholarly journals Using Welding Simulation and Ultrasonic Method to Evaluate Residual Stress in Stainless Steel Welded Plates

2012 ◽  
Author(s):  
Yashar Javadi ◽  
Mohammadreza Hadizadeh Raeisi ◽  
Hamed Salimi Pirzaman ◽  
Mehdi Ahmadi Najafabadi
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Acoustic Waves ◽  
Stress Measurement ◽  
Bulk Material ◽  
Three Dimensional ◽  
Ultrasonic Waves ◽  
Welding Simulation

When a material is under mechanical load, the stresses change the velocity of acoustic waves because of acoustoelastic effect. This property can be employed for stress measurement in the material itself when the stress concerns the surface of the material, or in the bulk material. This technique involves with critically refracted longitudinal waves that propagate parallel to the surface, i. e. LCR waves. This paper presents a three dimensional thermo-mechanical analysis to evaluate welding residual stresses in plate-plate joint of AISI stainless steel 304L. After finite element simulation, the residual stresses were evaluated by LCR ultrasonic waves. This paper introduces a combination of “Finite Element Welding Simulation” and “Ultrasonic Stress Measurement using the LCR Wave” which is called as “FELcr”. The capabilities of FELCR in residual stress measurement are confirmed here. It has been shown that predicted residual stress from three dimensional FE analyses is in reasonable agreement with measured residual stress from LCR method.

scholarly journals Direct measurement of the three-dimensional magnetization vector trajectory in GaMnAs by a magneto-optical pump-and-probe method

2012 ◽  
Vol 100 (10) ◽  
pp. 102403 ◽  
Author(s):  
N. Tesařová ◽  
P. Němec ◽  
E. Rozkotová ◽  
J. Šubrt ◽  
H. Reichlová ◽  
...  
Keyword(s):  
Direct Measurement ◽  
Three Dimensional ◽  
Magnetization Vector ◽  
Probe Method ◽  
Optical Pump ◽  
Pump And Probe

scholarly journals 3D Numerical Simulation of Hydro-Acoustic Waves Registered during the 2012 Negros-Cebu Earthquake

Geosciences ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 300
Author(s):  
Claudia Cecioni ◽  
Alessandro Romano ◽  
Giorgio Bellotti ◽  
Paolo De Girolamo
Keyword(s):  
Acoustic Signal ◽  
Acoustic Waves ◽  
Sea Water ◽  
Three Dimensional ◽  
The Philippines ◽  
Pressure Waves ◽  
Sea Bed ◽  
Weakly Compressible ◽  
Waves Propagation ◽  
Underwater Acoustic Signal

The paper investigates on the hydro-acoustic waves propagation caused by the underwater earthquake, occurred on 6 February 2012, between the Negros and Cebu islands, in the Philippines. Hydro-acoustic waves are pressure waves that propagate at the sound celerity in water. These waves can be triggered by the sudden vertical sea-bed movement, due to underwater earthquakes. The results of three dimensional numerical simulations, which solve the wave equation in a weakly compressible sea water domain are presented. The hydro-acoustic signal is compared to an underwater acoustic signal recorded during the event by a scuba diver, who was about 12 km far from the earthquake epicenter.

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