In this work, we applied the spectral element method (SEM) to analyze the dynamic characteristics of fluid conveying single-walled carbon nanotubes (SWCNTs). First, the dynamic equations for fluid conveying SWCNTs were deduced based on the nonlocal Timoshenko beam theory. Then, the spectral element formulation was established for a free/forced vibration analysis of fluid conveying SWCNTs by introducing discrete Fourier transform. Furthermore, the proposed method was validated using several comparison examples. Finally, the natural frequencies and dynamic responses of a simply-supported fluid conveying SWCNTs were calculated by the SEM, considering different internal fluid velocities and small-scale parameters (SSPs). The effects of fluid velocity and SSPs on the dynamic characteristics of SWCNTs conveying fluid were revealed by the numerical results. Compared with other methods, the SEM shows high accuracy and efficiency.

The Galerkin method is proposed to reveal the dynamic response of pipe conveying fluid (PCF), with lateral moving supports on both ends of the pipe. Firstly, the dynamic equation is derived by the Newtonian method after calculating the acceleration of the fluid element via the dynamics approach. Secondly, the discrete form of the dynamic equation is formulated by the Galerkin method. Thirdly, the numerical analysis of the system is carried out through the fourth‐order Runge–Kutta method, and the effectiveness of the proposed method is validated by comparison with the analytical results obtained by the mode superposition method. In the example analysis, the responses of the lateral deflection and bending moment are investigated for the pinned‐pinned, clamped‐pinned, and clamped‐clamped PCF. The effects of fluid velocity and the moving frequencies of supports are discussed. Especially, the deflection responses are analyzed under extreme condition; i.e., the moving frequency of a support is identical to the natural frequency of PCF.

Graph computing recently receives intensive interests due to a wide range of needs to analyse big graphs in real time. Many single-machine out-of-core graph computing systems have been developed to process large-scale graphs by utilizing effective memory access techniques. The current systems either focus on graph compression or pay attention to disk scheduling strategies. In this paper, we propose an efficient and unified out-of-core graph computing model on a single machine named D ² Graph which combines the differential storage strategy and the dynamic caching mechanism. D ² Graph improves the spatial locality of graph data and the temporal locality of graph computing at the same time. The main contributions of our work lie in three aspects: firstly, we design a fine-grained differential storage(FGDS) strategy to reorganize graph data on disk; secondly, we propose a dynamic caching mechanism (DCM) to selectively load the necessary edge chunks; thirdly, we combine FGDS and DCM to construct D ² Graph and evaluate it on five public graph data sets. What’s more, to optimize the performance of D ² Graph, we also make use of the multi-threaded parallel technology. A series of results show that D ² Graph outperforms state-of-the-art out-of-core graph computing systems by 1.3x-17.9x.

The pipeline bridge is a common structure in water transfer project. The external wind loads play an important role in the case of the flexible pipeline with large aspect ratio. In this paper, we investigate the dynamic response of cross-flow(CF) vortex-induced vibration(VIV) of pipeline bridge under external linearly sheared flow. Firstly, we apply the distributed van der Pol oscillator model to describe the location-dependent hydrodynamic loads on pipeline due to external sheared wind flow. And the dynamic equation of pipe with internal flow is deduced with the consideration of internal flow velocity, inner pressure and external tension. Secondly, the numerical analysis is conducted by central difference scheme. Finally, the lock-in response property and the effects of several factor, i.e. internal flow velocity, inner pressure, external tension and shear parameter, on the dynamic response are discussed in detailed. The results indicate that the multi-mode response always occurs in external sheared flow exhibits more complexity than single-mode response in external uniform flow. Among the above factors, the external tension has the greatest impact on dynamic response of pipeline bridge.