Directional attraction of fluid surface wave caused by vertically oscillating prisms

实验中发现三棱柱体在流体表面作低频小幅简谐振动时激发的表面波对漂浮物有定向吸引作用,针对此现象进行了系统实验和深入研究,分析了不同结构振源振动引起的流体表面波动的特性。开展了三棱柱体、四棱柱体、六棱柱体和圆柱体作为振源的实验。结果表明正对棱柱体棱边方向的表面波对漂浮物有吸引作用,而正对棱柱体柱面方向的表面波对漂浮物有排斥作用。吸引作用的大小与棱角的尖锐程度呈非线性关系,棱角越尖锐吸引作用越强。当振源为圆柱体即棱角消失时,表面波对漂浮物没有定向吸引作用。实验发现并验证了特定结构振源振动时产生的流体表面波具有定向吸引作用,研究成果可为水面污染物清理、海上溢油收集等工程应用问题提供帮助。</p

细长柔性体动力学仿真

本文研究了柔性细长体运动的动力学模型。细长柔性体在科学研究、工程和国防领域等都有广泛的应用，由于系统的复杂性，细长柔性体的运动稳定性、操纵性、安全性和和控制特性在使用之前都不容易进行完全的评估。本文建立了细长柔性体动力学模型，基于该模型建立了三维的计算仿真软件，并通过与实测数据的对比，检验了数值仿真结果

Simulation of Dam-break Flow with SPH Method

用光滑粒子法模拟几种情况的溃坝流动,对坝外无水和有水的情况进行二维模拟,对坝外有立柱的情况进行三维模拟.流动控制方程采用雷诺平均方程模拟溃坝流动的湍流效应,采用混合长度形式的涡粘模式对控制方程进行封闭,推导其相应的光滑粒子形式的方程.模拟结果表明,数值模拟的流动特征与实验结果符合得非常好,说明发展的光滑粒子法有效

Active compensating method of sensitivity temperature drift of convection-based Tilt sensor

When environment temperature is changed, the properties of convection-based tilt sensors are changed, which is so-called sensitivity temperature drift. Methods of sensitivity compensation are introduced according to mechanism of this kind of tilt sensor: temperature distribution induced by the heat source plays a key role in sensing tilt angle. The sensitivity temperature drift was researched, a new method of sensitivity temperature active compensating was proposed, and sensitivity temperature active compensating was accomplished

Influence of heat-source temperature on convection-based tilt sensor output

According to the sensitive mechanism of convection-based tilt sensor, temperature field plays a key role in the sensing tilt. The tilt sensor output has one to one correspondence with the temperature field, which is variety with heat-source temperature. Using ANSYS, temperature flow fields are simulated by variety heat-source temperatures in a two dimension hermetic chamber, the differences of temperature between hotwires are obtained, the outputs based on these are calculated, also compared with measured values. From the results the output relation with the heat-source temperature is given qualitatively1. Figurate; qualltative, through this relation the output of sensor can be improved, meanwhile output drifted with heat-source temperature can be decreased by provided circuit

“升力推力”飞行器技术分析

大气层中的高超声速巡航飞行,将是继喷气发动机时代之后航空发展的又一里程碑,而飞行器设计的"升阻比"屏障也是继热障、黑障之后的又一技术关键。"升力推力"飞行器是根据新世纪对高超声速飞行器的需求提出的一种新型飞行器概念,它可以使飞行器的升阻比得以有效提高。本文对"升力推力"飞行器概念及其动力进行了技术分析,并对其未来的发展进行了展望

Simulation of Water Entry with Smoothed Particle Hydrodynamics Method

利用LANS-α(Lagrangian-averaged Navier-Stokes-alpha)模型对传统的光滑粒子法进行改进.通过模拟半浮力和零浮力水平圆柱的入水过程,验证改进的光滑粒子法.模拟结果与实验以及其它数值模拟结果符合的很好,表明改进的光滑粒子法适用于研究物体入水问题