Nonlinear Dynamical Interaction Between Insonified Microbubbles

2012 ◽  
Author(s):  
Akira Tsuruoka ◽  
Hiroki Kubo ◽  
Toshihiko Sugiura
Keyword(s):  
Numerical Simulation ◽  
Natural Frequency ◽  
Pressure Change ◽  
Diameter Ratio ◽  
Analytical Prediction ◽  
Ultrasonic Therapy ◽  
Dynamical Interaction ◽  
Nonlinear Dynamical ◽  
Close Distance ◽  
Two Bubbles

Microbubbles are expected to be applied for ultrasonic therapy. In this research, considering two neighboring bubbles, we added to the Rayleigh-Plesset equation the term of nonlinear influence corresponding to pressure change caused by the neighboring bubble’s oscillation, and numerical simulation was performed. It is known that the natural frequency of a microbubble decreases with increasing the bubbles’ density. This fact agrees with our analytical prediction based on the Rayleigh-Plesset equation. Further, the natural frequency also depends on the diameter ratio of the two bubbles. Our numerical results show that superharmonic response reaches a peak at some distance between bubbles when they are driven at half their resonance frequency with their ratio of the natural frequency being two to one. Numerical simulation also shows that if the two bubbles of the same size exist at a close distance, the occurrence region of the subharmonics is larger than that of a single bubble.

Numerical Analysis on the Electrical Performance of Microstructured Environmentally-Friendly Electrical Contact Material Ag/SnO2

2013 ◽  
Vol 419 ◽  
pp. 355-359
Author(s):  
Lei Wang ◽  
Wei Li Liu ◽  
Le Sheng Chen
Keyword(s):  
Numerical Simulation ◽  
Electrical Contact ◽  
Environmentally Friendly ◽  
Weight Percent ◽  
Diameter Ratio ◽  
Electrical Performance ◽  
Structural Parameter ◽  
Contact Material ◽  
Electrical Contact Material ◽  
Length To Diameter Ratio

The paper analyzes the influence of structural parameters on the electrical performance of the microstructured environmentally-friendly electrical contact material Ag/SnO2 by using numerical simulation method.The numerical results show that the reisitivity of fiber-like electrical contact material Ag/SnO2 is significantly reduced compared with the resistivity of Ag/SnO2 adding reinforcing nanoparticles in the traditional way.So the fiber-like electrical contact material Ag/SnO2 exhibits higher conductivity in macro. On further analysis, we learn that the resistivity of fibrous electrical contact materials is related to weight percent of reinforced phase, and micro-structural parameter of length to diameter ratio. The resistivity increases as weight percent of reinforced phase increases,and decreases non-linearly with micro-structural parameter of length to diameter ratio increasing.This demonstrates that numerical simulation is one of effective methods for analysis of the electrical performance of the microstructured electrical contact material.

Dynamical Interaction of Solar Magnetic Elements and Granular Convection: Results of a Numerical Simulation

1998 ◽  
Vol 495 (1) ◽  
pp. 468-484 ◽  
Author(s):  
O. Steiner ◽  
U. Grossmann‐Doerth ◽  
M. Knolker ◽  
M. Schussler
Keyword(s):  
Numerical Simulation ◽  
Dynamical Interaction ◽  
Magnetic Elements

The Research of Calculation Method on Vertical Natural Frequency of the New Full-Prefabricated Floor

2016 ◽  
Vol 846 ◽  
pp. 506-511
Author(s):  
Chong Fang Sun ◽  
Shu Ting Liang ◽  
Xiao Jun Zhu
Keyword(s):  
Numerical Simulation ◽  
Natural Frequency ◽  
Calculation Method ◽  
Variable Stiffness ◽  
Series Method ◽  
Numerical Simulation Result ◽  
Stiffness Method ◽  
Calculation Results ◽  
New Type ◽  
Test Result

New-type floor is composed of three kinds of slabs joined together through fittings. It is a kind of anisotropic two-way slab. In order to study the calculation method of natural frequency, series method, variable thickness method and variable stiffness method are adopted to calculate the natural frequency. The calculation results of three methods are compared with test result and numerical simulation result. The conclusion is that the calculation result of the variable stiffness method is the closest to the real natural frequency of new-type floor.

Study on Numerical Simulation and Performance of the Secondary Throttle Choke Used in the Oil Field

2013 ◽  
Vol 712-715 ◽  
pp. 1201-1204
Author(s):  
Hai Feng Zhao ◽  
Yan Xu
Keyword(s):  
Numerical Simulation ◽  
Pressure Change ◽  
Simulation Method ◽  
Differential Pressure ◽  
Oil Field ◽  
Pressure Curve ◽  
Flow Pressure ◽  
Flow Changes ◽  
And Performance ◽  
Main Factor

The numerical simulation method is adopted to calculate the flow field of the secondary throttle choke used in the oil field. The relationships among the flow of the secondary throttle choke, differential pressure and diameters are studied. The results of numerical simulation coincide with the experiment values, which verify that the method is correct. The results show that the flow increases with the increasing of differential pressure of the throttle choke at both ends, but the increment of the flow gradually decreases. The structure could maintain the flow not to change basically when differential pressure change in a certain scope. When the throttle diameter turns out to be small, the flow decreases, and flow-pressure curve gradually becomes aclinic. Compared with the first-class throttle diameter, the second-class throttle diameter is the main factor which effects flow changes.

Numerical Simulation and Analysis for Influence of Wall Effect on Cavity Shape

2013 ◽  
Vol 385-386 ◽  
pp. 400-403
Author(s):  
Fu Yuan Li ◽  
Yu Wen Zhang ◽  
Xi Zhao Du
Keyword(s):  
Numerical Simulation ◽  
Simulation Model ◽  
Empirical Formula ◽  
Diameter Ratio ◽  
Cavitation Number ◽  
Wall Effect ◽  
Water Tunnel ◽  
Cavity Shape ◽  
Model Size ◽  
The Impact

In the experiment of cavitation, the same water tunnel with different model size will get cavity shape that is different from the result of the empirical formula under the same cavitation number. In this article, we studied the impact of wall effect on natural cavity shape and the resistance of cavitator. We get the cavity shape and resistance of cavitator under different diameter ratio. We also get the law how cavity shape and resistance of cavitator change with the diameter ratio. The results provide a reference for experiment in water tunnel and the simulation model.

Sloshing and Swirling in Partially Loaded Prismatic Chamfered Tanks

2017 ◽  
Author(s):  
Gustavo M. Karuka ◽  
Makoto Arai ◽  
Hideyuki Ando
Keyword(s):  
Numerical Simulation ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Pressure Distribution ◽  
Natural Frequency ◽  
Difference Method ◽  
Simulation Data ◽  
Tank Model ◽  
Breadth Ratio ◽  
Sloshing Pressure

In this study a sloshing experiment using a partially filled membrane tank model was carried out and compared with numerical simulation. The pressure was measured at 10 points and a load cell measured the longitudinal and transversal forces, under regular and irregular excitation. A 3D finite difference method based solver was used for the numerical simulation. When the prismatic tank length to breadth ratio is near 1, swirling, i.e., liquid free surface’s rotating motion in the tank might occur when the tank is excited near its natural frequency, especially for medium and low tank filling levels. According to the experimental and simulation data, the magnitude of the forces and impact pressures in this situation can be significant and therefore cannot be neglected. Tank designs might use different length to breadth ratios (Lt/Bt) depending on the ship size and number of tanks, so the problem is worth being investigated. The Lt/Bt and the occurrence of swirling was then investigated. The pressure distribution when the swirling occurs is then compared with the 1st mode sloshing pressure distribution, and considerations about the tank safety are inferred.

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