scholarly journals Numerical and Experimental Verification of Stress Wave Control Effect in SHPB Experiment using Pulse Shaper

2017 ◽  
Vol 26 (5) ◽  
pp. 314-322 ◽  
Author(s):  
Y.H. Kim ◽  
M.A. Woo ◽  
B.S. Kang ◽  
J. Kim
Keyword(s):  
Stress Wave ◽  
Experimental Verification ◽  
Pulse Shaper ◽  
Control Effect ◽  
Wave Control

scholarly journals Numerical Analysis of Stem Wave Control Effect of a Curved Slit Caisson Breakwater

2021 ◽  
Vol 8 (3) ◽  
pp. 181-192
Author(s):  
Yong Jun Cho
Keyword(s):  
Wave Interaction ◽  
Structural Type ◽  
Effective Control ◽  
Control Effect ◽  
Design Factor ◽  
The Past ◽  
Resonance Wave ◽  
Caisson Breakwater ◽  
Rough Sea ◽  
Wave Control

Curved slit caisson has been the preferred structural type of breakwater in South Korea, and effective control of stem waves is a crucial design factor significantly affecting the performance of a curved slit caisson breakwater. Most of the past studies on stem waves heavily relied on wave drivers like the cubic Schrödinger Eq. due to the intrinsic difficulties in analyzing stem waves. However, considering the perturbation method evoked in the derivation of cubic Schrödinger Eq., the wave driver mentioned above could give erroneous results in the rough sea due to the higher-order waves that appeared in the wave field by resonance wave-wave interaction. In this rationale, in this study, the numerical simulation was implemented to verify the stem wave control effect of curved slit caisson using the ihFoam, toolbox having its roots on OpenFoam. It was shown that curved slit caisson breakwater effectively alleviates the scope and height of stem waves.

scholarly journals Experimental Study on Ramp Shock Wave Control in Ma3 Supersonic Flow Using Two-Electrode SparkJet Actuator

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1679
Author(s):  
Wei Xie ◽  
Zhenbing Luo ◽  
Yan Zhou ◽  
Lin Wang ◽  
Wenqiang Peng ◽  
...  
Keyword(s):  
Shock Wave ◽  
Supersonic Flow ◽  
Flow Field ◽  
Pressure Measurement ◽  
Separation Zone ◽  
Dynamic Pressure ◽  
Base Flow ◽  
Control Effect ◽  
Dynamic Pressure Measurement ◽  
Wave Control

The control of a shock wave produced by a ramp (ramp shock) in Ma3 supersonic flow using a two-electrode SparkJet (SPJ) actuator in a single-pulse mode is studied experimentally. Except for schlieren images of the interaction process of SPJ with the flow field, a dynamic pressure measurement method is also used in the analysis of shock wave control. In a typical experimental case, under the control of single-pulsed SPJ, the characteristic of ramp shock changes from “short-term local upstream motion” in the initial stage to “long-term whole downstream motion” in the later stage. The angle and position of the ramp shock changes significantly in the whole control process. In addition, the dynamic pressure measurement result shows that the ramp pressure is reduced by a maximum of 79% compared to that in the base flow field, which indicates that the ramp shock is significantly weakened by SPJ. The effects of some parameters on the control effect of SPJ on the ramp shock are investigated and analyzed in detail. The increase in discharge capacitance helps to improve the control effect of SPJ on the ramp shock. However, the control effect of the SPJ actuator with medium exit diameter is better than that with a too small or too large one. In addition, when the SPJ exit is located in the separation zone and outside, the change in the ramp shock shows significant differences, but the control effect in the case of medium ramp distance is better when the SPJ exit is located outside the separation zone.

New control strategy for suppressing the local vibration of sandwich beams based on the wave propagation method

2021 ◽  
pp. 1045389X2110188
Author(s):  
Jun Xu ◽  
Yandong Chen ◽  
Yongpeng Tai ◽  
Guodong Shi ◽  
Ning Chen ◽  
...  
Keyword(s):  
Vibration Control ◽  
Control Strategy ◽  
Control Method ◽  
Flow Direction ◽  
Operating Conditions ◽  
Control Effect ◽  
Linear Quadratic ◽  
Local Vibration ◽  
Viscoelastic Composite ◽  
Wave Control

The general vibration control strategy of beam structures is a global vibration control method based on the principle of modal superposition. However, the vibration wave control of beams can achieve local control of the vibration energy. This paper presents a wave control method for the local vibration control of fractional viscoelastic composite beams based on the operating principle of a piezoelectric sheet. To obtain better control performance, a particle swarm optimization algorithm was adopted to optimize the parameters of the piezoelectric sheet. A linear quadratic regulator control algorithm was designed to verify the validity of the proposed method. In addition, the effects of the piezoelectric sheet number and fractional order on the amplitude response and optimization parameters were investigated. We observed that the proposed method has a good control effect on the local area vibration, and it can control the flow direction of the vibration power. The proposed method can be used to directly design the voltage and phase of a piezoelectric sheet without real-time feedback computation. This method is suitable for reducing local vibration under single repetitive operating conditions in engineering and can provide a theoretical basis for a follow-up study on the acoustic black hole phenomenon.

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