Analysis of pressure wave signal generation in MPT: An integrated model and numerical simulation approach

2021 ◽  
pp. 109871
Author(s):  
Hu Han ◽  
Liang Xue ◽  
Honghai Fan ◽  
Xianbo Liu ◽  
Min Liu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Pressure Wave ◽  
Integrated Model ◽  
Signal Generation ◽  
Simulation Approach ◽  
Wave Signal

Numerical Simulation Study on High-Temperature Ventilated Cavitating Flow Considering the Compressibility of Gases

2012 ◽  
Vol 569 ◽  
pp. 395-399
Author(s):  
Jing Zhao ◽  
Guo Yu Wang ◽  
Yan Zhao ◽  
Yue Ju Liu
Keyword(s):  
Numerical Simulation ◽  
State Equation ◽  
Field Structure ◽  
Cavitating Flow ◽  
Simulation Approach ◽  
Gas Velocity ◽  
Simulation Data ◽  
Ventilated Cavity ◽  
Supercavitating Flow ◽  
Fluctuation Range

A numerical simulation approach of ventilated cavity considering the compressibility of gases is established in this paper, introducing the gas state equation into the calculation of ventilated supercavitating flow. Based on the comparison of computing results and experimental data, we analyzes the differences between ventilated cavitating flow fields with and without considered the compressibility of gases. The effect of ventilation on the ventilated supercavitating flow field structure is discussed considering the compressibility of gases. The results show that the simulation data of cavity form and resistance, which takes the compressibility of gases into account, accord well with the experimental ones. With the raising of ventilation temperature, the gas fraction in the front cavity and the gas velocity in the cavity increase, and the cavity becomes flat. The resistance becomes lower at high ventilation temperature, but its fluctuation range becomes larger than that at low temperature.

scholarly journals RANDOM WAVE SIGNAL GENERATION BY MINICOMPUTER

1974 ◽  
Vol 1 (14) ◽  
pp. 19 ◽  
Author(s):  
Ed. R. Funke
Keyword(s):  
Digital Filter ◽  
Transfer Functions ◽  
Noise Generator ◽  
Shift Register ◽  
Signal Generation ◽  
Random Wave ◽  
Wave Signal ◽  
Binary Feedback ◽  
Feedback Shift Register ◽  
Wave Maker

The computer programmed implementation of a pseudorandom noise generator based on the use of a binary feedback shift register and an associated digital filter is described. Descriptive details are given for the compensation of the filter for the various dynamic transfer functions in the system. The random signal generator has been programmed both for a dedicated computer (NOVA 1200 with 4K core) which can carry up to 50 different spectra in core at any one time and for the EAI 64 0 with 16K core and disc storage which was used to investigate the spectral and statistical properties of the generated wave. JONSWAP spectra with 0.6 and 1.0 Herz centre frequencies were generated and observed at locations from 5 to 40 meters from the wave maker using a hydraulically operated machine in a partial piston and partial hinged flap mode m 0.9 meter of water. Measurements indicate that JONSWAP spectra can be closely matched in the flume. The 1.0 Herz spectrum is less stable as a function of distance, all spectra indicate a significant decrease of the spectral peak as a function of distance from the wave maker and the ratio of ^xaax/^av ls ln general larger than that observed by Wiegel and Kukk.

scholarly journals On Numerical Simulation Approach for Multiple Resonance Modes in Servo Systems

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Qixin Zhu ◽  
Hongli Liu ◽  
Yiyi Yin ◽  
Lei Xiong ◽  
Yonghong Zhu
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Closed Loop ◽  
Resonance Mode ◽  
Servo Control ◽  
Simulation Approach ◽  
Servo Systems ◽  
Resonance Modes ◽  
Resonant Part ◽  
The Mathematical Model

Mechanical resonance is one of the most pervasive problems in servo control. Closed-loop simulations are requisite when the servo control system with high accuracy is designed. The mathematical model of resonance mode must be considered when the closed-loop simulations of servo systems are done. There will be a big difference between the simulation results and the real actualities of servo systems when the resonance mode is not considered in simulations. Firstly, the mathematical model of resonance mode is introduced in this paper. This model can be perceived as a product of a differentiation element and an oscillating element. Secondly, the second-order differentiation element is proposed to simulate the resonant part and the oscillating element is proposed to simulate the antiresonant part. Thirdly, the simulation approach for two resonance modes in servo systems is proposed. Similarly, this approach can be extended to the simulation of three or even more resonances in servo systems. Finally, two numerical simulation examples are given.

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