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Dynamic analysis of finger seal can be performed by finite element method or equivalent model based on lumped mass method now available, which is difficult in meeting both the acceptable calculation time and accuracy simultaneously. For this reason, interactions between finger elements are considered and the equivalent dynamic model based on distributed mass method is proposed in this article. Seal dynamic performances are obtained by using this model to calculate the equivalent parameters, air leakage flow, and the contact behavior between finger seal and the rotor. The work to be presented here concerns the mapping of dynamic behavior of the finger seal with a stack of three finger elements, including the dynamic displacement responses of finger elements, the leakage clearances, and the contact pressures between the finger elements and the rotor, as well as the leakage flow rate and the wear rate. The results calculated by the equivalent model presented in this study are evaluated by comparison with the published experimental data and results from the model based on lumped mass method, which shows that the equivalent model based on distributed mass method is far superior to that based on lumped mass method because the calculations are in good agreement with the experimental results.

High-speed and accurate simulations of landslide-generated tsunamis are of great importance for the understanding of generation and propagation of water waves and for prediction of these natural disasters. A three-dimensional numerical model, based on Reynolds-averaged Navier–Stokes equations, is developed to simulate the landslide-generated tsunami. Available experiment data is used to validate the numerical model and to investigate the scale effect of numerical model according to the Froude similarity criterion. Based on grid convergence index (GCI) analysis, fourteen cases are arranged to study the sensitivity of numerical results to mesh resolution. Results show that numerical results are more sensitive to mesh resolution in near field than that in the propagation field. Nonuniform meshes can be used to balance the computational efficiency and accuracy. A mesh generation strategy is proposed and validated, achieving an accurate prediction and nearly 22 times reduction of computational cost. Further, this strategy of mesh generation is applied to simulate the Laxiwa Reservoir landslide tsunami. The results of this study provide an important guide for the establishment of a numerical model of the real-world problem of landslide tsunami.

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Study on the motion and thermal states of oil droplet is an important part of research on the oil/air two-phase flow and heat transfer in an aero engine bearing chamber. In this paper, dimensional analysis is applied to the airflow analysis of bearing chamber. That makes the analysis model suitable for a wide range of geometric and operating conditions. Moreover, the temperature solution is added to the oil droplet motion analysis. That could promote the calculation accuracy of the droplet trajectory, velocity, and temperature. Firstly, the similarity criteria of the airflow in a bearing chamber are determined based on the dimensional analysis. The airflow distribution general formulas are proposed based on the numerical results of airflow velocity and temperature. The general formulas include 14 similarity criteria and are suitable for various geometric and operating conditions. The reliability of the general formulas is verified by some available experimental results. Secondly, the difference equations of the oil droplet velocity and temperature are listed by the difference method. The velocity and temperature of the droplet are obtained using a step-by-step method. The influence of droplet diameter, shaft rotational speed, air flow rate, and temperature on the oil droplet trajectory, velocity, and temperature are discussed. Thirdly, a test facility is built in order to investigate into the oil droplet motion and thermal states in a bearing chamber. The trajectory and velocity of the oil droplet are measured by the high-speed photography. Lastly, the proposed theoretical method about the oil droplet motion and thermal states is verified by above measurement results. The work in this paper may have a certain significance for perfecting the research system and improving the research level on the oil/air two-phase flow and heat transfer in an aero engine bearing chamber.