基于DFT系数插值的频率估计算法的改进

针对当前信号频率估计常规算法或计算量大或低信噪比(SNR)时精度低等问题,引入了一种简单的静态插值方法。该方法利用离散傅立叶变换(DFT)的谱分量及其附近插入的两个傅氏分量系数进行频率估计,有效地改善了估计精度,减少了计算量,在低SNR时效果仍然良好。     

某330 kV输电线路铁塔利旧分析

针对新建输电线路工程中存在的铁塔利旧问题,分析了新建工程的气象条件和导地线型号与原有铁塔的设计使用条件不一定完全相符的工程设计条件.通过按新设计条件验算、校核,得出对原有塔型不能铁塔利旧,以防止出现以小带大的情况,给工程安全带来隐患.     

Modelling of 2-D extended Boussinesq equations using a hybrid numerical scheme

In this paper, a hybrid finite-difference and finite-volume numerical scheme is developed to solve the 2-D Boussinesq equations. The governing equations are the extended version of Madsen and Sorensen＇s formulations. The governing equations are firstly rearranged into a conservative form. The finite volume method with the HLLC Riemann solver is used to discretize the flux term while the remaining terms are discretized by using the finite difference method. The fourth order MUSCL-TVD scheme is employed to reconstruct the variables at the left and right states of the cell interface. The time marching is performed by using the explicit second-order MUSCL-Hancock scheme with the adaptive time step. The developed model is validated against various experimental measurements for wave propagation, breaking and runup on three dimensional bathymetries.