In this paper, a novel multi-dimensional complex non-equilibrium phase transition model is put forward to describe quantitatively the physical development process of turbulence and develop the Kolmogorov turbulence theory from the catastrophe theory, in which the well-known −5/3 power law is only a special case in this paper proving the accuracy of our methods. Catastrophe theory is a highly generalized mathematical tool that summarizes the laws of non-equilibrium phase transition. Every control variable in catastrophe theory could be skillfully expanded into multi-parameter multiplication with different indices and the relationship among these characteristic indices can be determined by dimensionless analysis. Thus, the state variables can be expressed quantitatively with multiple parameters, and the multi-dimensional non-equilibrium phase transition theory is established. As an example, by adopting the folding catastrophe model, we strictly derive out the quantitative relationship between energy and wave number with respect to a new scale index [Formula: see text] to quantitative study the whole process of the laminar flow to turbulence, in which [Formula: see text] varies from [Formula: see text] to [Formula: see text] corresponding to energy containing range and [Formula: see text] to energy containing scale where [Formula: see text] power law is deduced, and at [Formula: see text] the [Formula: see text] law of Kolmogorov turbulence theory is obtained, and fully developed turbulence phase starts at [Formula: see text] giving [Formula: see text] law. Furthermore, this theory presented is verified by our wind tunnel experiments. This novel non-equilibrium phase transition methods cannot only provide a new insight into the turbulence model, but also be applied to other non-equilibrium phase transitions.

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Knowledge-intensive is a significant feature of the modern service-oriented industrial structure, and knowledge service is a main part of knowledge science. With research practices and accumulations in the field of tribological knowledge acquisition of turbine, automobile engines and other complex mechanical systems, construction of knowledge base and cooperation with enterprises in chain of “University-Industry-Research”, based on the understanding and experience of conceptual contents and features of tribology, knowledge service and resource unit and other concepts in the process of utilization, this paper studied the expression of modeling knowledge in the process of basic tribological knowledge service, construction of knowledge unit based on knowledge base and the driving force of knowledge acquisition and knowledge flow.

Based on the description of 20MN fast forging press hydraulic system, the paper analyzed the possibility of energy conservation which the accumulator made in the fast forging machine system. When accumulator was used in fast forging machine, then analyzed the calculation results, and the energy conservation program of fast forging machine energy accumulator was evaluated briefly. The test system was set up on 20MN fast forging machine, and the paper researched the application of accumulator in fast forging press hydraulic system on absorbing hydraulic shock and eliminating pressure pulsation.

In this paper, a Multiphysics coupling simulation model of flow and acoustics is proposed using COMSOL software, and its results are verified by comparing with experimental results of others. Then, the aerodynamic pressure above the bluff body surface at a speed of 350 km/h is simulated. Moreover, a near-zero-impedance acoustic metasurface composed of periodic square cavities is theoretically studied with respect to the lowest acoustic pressure, which is consistent with simulation results. The wake vortices are greatly reduced due to the suction effect formed in the cavities when the fluid flow passes through the square-cavity metasurface. The vertical velocity above the square-cavity boundary is significantly increased, essentially leading to the decrease in acoustic impedance. The presence of high-speed fluid flow weakens the attenuation effect of the square-cavity acoustic metasurface on the acoustic field. The reduction in wake vortices and the near-zero-impedance of the boundary fundamentally suppress the acoustic pressure fluctuation above the bluff body surface. Finally, large broadband suppression of aerodynamic pressure and 7.3 dB reduction in the average acoustic pressure level are realized with the periodic acoustic metasurface. The greater the porosity of the square cavities, the smaller the fluctuating pressure amplitude. This work provides a new idea for the complete control of the aerodynamic pressure in a high-speed flow field and shows a great engineering application prospect.