基于交互多模型的水下目标跟踪方法

According to the requirements of real-time performance and reliability in underwater maneuvering target tracking as well as clarifying motion features of the underwater target, an interacting multiple model algorithm based on fuzzy logic inference （FIMM） is proposed. Maneuvering patterns of the target are represented by model sets, including the constant velocity model （CA）, the Singer mode~, and the nearly constant speed horizontal-turn model （HT） in FIMM technology. The simulation results show that compared to conventional IMM, the reliability and real-time performance of underwater target tracking can be improved by FIMM algorithm.     

利用FHT法反演海洋重力

从快速 Hartley变换 (FHT)基本概念入手 ,给出了 Hotine核在平面近似、球面近似、Molodenskii近似下的反演模型。另对 FHT处理中所需的坐标转换以及边缘效应等问题加以讨论。同时 ,为了改善长波特性的重力场信息 ,利用 M阶次的参考重力场对上述 Molo-denskii模型进行了改化。     

Experimental investigation of drag coefficients of gobi surfaces

The response of gobi surfaces to the near-surface air flow can be characterized quantitatively by drag coefficients. By using wind tunnel tests, an attempt is made to define the relationship between the drag coefficients of gobi surfaces and gravel size and coverage. It is concluded that the drag coefficients of gobi surfaces tend to be constants when gravel coverage is over 40%-50%. Consequently, we think that the gobi deflation planes expanding vastly in the arid Northwestern China are aerodynamically stable, at least not the supplying sources of current dust storms, and therefore the emphasis on dust storm control should be paid on the so-called "earth gobi" that has low gravel coverage. The prediction model for drag coefficients of gobi surfaces has been developed by regressing drag coefficients on gravel size and coverage, the predicted results are in reasonably good agreement with wind tunnel results (R 2 = 0.94). The change of drag coefficients with gravel friction Reynolds number implies that the development extent of drag effect increases with gravel size and coverage.     

Dynamic response of single piles embedded in transversely isotropic layered media

Dynamic response of single piles embedded in transversely isotropic layered media is investigated using the finite element method combined with dynamic stiffness matrices of the soil derived from Green's functions for ring loads. The influence of soil anisotropy on the dynamic behaviour of piles is examined through a series of parametric studies.     

MATHEMATICAL MODELS FOR LIQUID-SOLID TWO-PHASE FLOW

I INTRODUCTIONTurbulence models for single-phase fluid flows have been developed and widely applied in mechanical,aeronautical, environmental and hydraulic engineering, and other fields. The closure techniques for theReynolds-averaged Navier-Stokes equations for various levels of models including the simple turbulencemodel, one-equation turbulence model, k-s turbulence model and turbulence stress/flux model have beenverified to be physically reasonable and have acceptable accuracy in app…     

某高层建筑模型振动台试验结果分析

本文分析了广州市某２８层高层建筑模型模拟地震振动台试验结果,对此建筑的抗震性能进行了评价,考究了设置摩擦耗能支对其动力反应的减震作用。     

Numerical simulation of solitary and randomwave propagation through vegetation based on VOFmethod

A vertical two-dimensional numerical model has been applied to solving the Reynolds Averaged Navier- Stokes （RANS} equations in the simulation of current and wave propagation through vegetated and non- vegetated waters. The k-e model is used for turbulence closure of RANS equations. The effect of vegeta- tion is simulated by adding the drag force of vegetation in the flow momentum equations and turbulence model. To solve the modified N-S equations, the finite difference method is used with the staggered grid system to solver equations. The Youngs＇ fractional volume of fluid （VOF） is applied tracking the free sur- face with second-order accuracy. The model has been tested by simulating dam break wave, pure current with vegetation, solitary wave runup on vegetated and non-vegetated channel, regular and random waves over a vegetated field. The model reasonably well reproduces these experimental observations, the model- ing approach presented herein should be useful in simulating nearshore processes in coastal domains with vegetation effects.     

江南隆起带中段新元古代花岗岩锆石U-Pb年代学和Hf同位素组成研究

对江南隆起带中段湘东西园坑岩体和赣西九岭岩体的LA-ICPMS锆石U-Pb年代学测定和LA-MC-ICPMS锆石Hf同位素原位分析测试表明:西园坑岩体形成于(804±3)Ma,赣西九岭岩体的年龄为(813±4)Ma和(823±2)Ma,均为新元古代花岗岩.上述三个样品的εHf(t)的加权平均值分别为0.68±0.71,...     

地震作用下多层剪切型组合结构的合理综合阻尼比取值探讨

对于组合结构,提出了一种新的基于单元瑞利阻尼模型的应变能振型阻尼比,并证明了其在特定整体阻尼矩阵下与强迫解耦法的等价性;推导了具有明确理论依据的综合阻尼比计算公式,并基于相应的应变能振型阻尼比得出了结构的刚度综合阻尼比和瑞利综合阻尼比。分别采用复振型分解法和振型分解法对算例结构进行了地震荷载作用下的弹性时程分析,结果表明,瑞利综合阻尼比对于以剪切变形为主的多层组合结构具有良好的计算精度和适用性。     

A 3-D finite volume model for sediment transport in coastal waters

Ocean Dynamics - A 3-D model has been developed to simulate sediment transport and bed change induced by currents and waves in coastal waters. The currents are calculated with the 3-D...