This paper is concerned with the study of a kind of discrete forcing immersed boundary method (IBM) by which the loosely aero-elasticity coupled method is developed to analyze turbine blade vibration. In order to reduce the spurious oscillations at steep gradients in the compressible viscous flowing field, a five orders weighted essentially nonoscillatory scheme (WENO) is introduced into the flow solver based on large eddy simulation (LES). The three-dimensional (3D) full-annulus domain of the last two stages of an industrial steam axial turbine is adopted to validate the developed method. By the method, the process of grid generation becomes very simple and the unsteady data transferring between stator and rotor is realized without the process of being averaged or weighted. Based on the analysis of some important aerodynamic parameters, it is believed that hypothesis of azimuthal periodicity is not reasonable in this case and full-annulus passages model is more feasible and suitable to the research of turbine blade vibration. Meanwhile, the blade vibration data are also discussed. It is at about 65% of rotor blade height of the last stage that an inflection point is observed and the midspan region of the blade is the vulnerable part damaged potentially by the blade vibration.
The evaluation method of load transfer efficiency using falling weight deflectometer is unworkable in remote mountain areas and transportation difficult region. Therefore, a novation method of load transfer efficiency evaluation is proposed using the index of amplitude ratio. Finite element method is applied to study the influence of dowel bar parameters (diameter, length, spacing, and elastic modulus) and pavement structures parameters (thickness and modulus) on load transfer efficiency, frequency, and the ratio of amplitude. Results of finite element model show that the effects of dowel bar and pavement structure parameters on load transfer efficiency and the ratio of amplitude are similar. The load transfer efficiency, frequency, and the ratio of amplitude enhance with the increase of dowel bar diameter, length, and elastic modulus and the decrease of dowel bar spacing. The subgrade modulus has more significant influence on the load transfer efficiency, frequency, and the ratio of amplitude than other pavement parameters. Polynomial function method is utilized to established load transfer mode between deflection-based load transfer efficiency and the ratio of amplitude. The feasibility and reliability of new method is verified by static and dynamic load test. All results are helpful for the development of highway engineering and airport engineering.
Low-impact development measures are a kind of ecological technology system that can easily realize urban rainwater collection and utilization to alleviate the contradiction between flooding/water logging disasters and water shortages. But most of the low-impact development measures are difficult to solve the problem of deep soil infiltration and fully utilize runoff regulation and seepage benefits. Therefore, this paper proposes the concrete microseepage well with the optimum proportion of crushed stone, cement, and water of 1 : 0.13 : 0.11 and 2% steel fiber content. The artificial rainfall experiment is applied to verify the high-infiltration of concrete microseepage well in deep soil. The numerical analysis shows that the concrete microseepage well around a single building and two adjacent buildings can all decrease 15%–40% of the pore water pressure, decrease 11%–33% of total head, and improve 43–55 times of infiltration velocity. The concrete microseepage well with 0.1 m in diameter and 1 m in height can affect the infiltration area of 1 m2. Each building being surrounded by seepage wells is the optimal layout scheme to alleviate the flooding/water logging disasters. This study provides a scientific reference for the development of sponge cities with low-impact development measures to reduce the problem of flooding/water logging disasters and water shortages.
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