After the author introduces Hilbert-Huang Transform which is a new signal analysis theory, he tests the stationarity of typical time domain data of stochastic fluctuant pressure making use of turn method and HHT method respectively. From that, he concludes that stochastic fluctuant pressure on radial gate can be treated asstationary random process going through all of states in the case of certain opening and the characteristic value can be obtained from random function theory and spectrum analysis.
Making use of this simplified mechanics model, the time domain method of dynamic load identification is put to use on the basis of modal analysis method. And the simulation analysis about stochastic fluctuant load identification on radial steel gate manifests the feasibility and the effectiveness in hydraulic structure.
Surface deformation is fluctuant with time, which shows the character of surface wave.
Simulation study on fluctuant flow stress scale effect
Crystal plasticity theory was used to simulate upsetting tests of different dimensions and grain size micro copper cylinders in this study on the fluctuant flow stress scale effect.
Through this study, the fluctuant flow stress scale effect can be understood deeper, and relevant necessary information was obtained for further prediction and control of this scale effect and to design the microforming process and die.
At least two episodes of cyanobacterial expansion are documented by 2-methylhopanes ranging from C28 to C32 in carbon number, indicative of the instable marine ecosystem and the fluctuant aquatic nutrients.
A theoretical formula indicating the influence factors of the Rheingans number is derived from which the tendency of the hydro-vibration frequency to increase with the decreasing guide opening of the Francis turbine is explained.The phenomenon of pressure fluctuation amplitude varying with the operating condition is analysed with two pressure gradient equations.
The relations between the pressure fluctuation and velocity distribution in the draft tube of a Francis turbine and the unit speed n', and the unit discharge Q'1 as well as that between the relative amplitude (H) of pressure fluctuation and the outlet peripheral velocity of turbine runner (V2u) are discussed, with a preliminary survey of the mechanism of pressure fluctuation.