舰船尾迹气泡上浮运动的一种表征模型

气泡上浮运动是舰船远程尾迹气泡场特征的重要组成部分。本文首先综合考虑水中气泡上浮与扩散传质这两个相互耦合的因素,构建了能够表征舰船远程尾迹场中气泡上浮运动的数学模型：进而利用该模型计算分析了远程尾迹气泡场气泡数密度的变化情况,计算值与实验结论吻合良好,表明了该模型的正确性与应用价值。     

LPG发动机缸内Nox分布及其排放的预测研究

借助CFD软件Star-CD,将基于β函数的概率密度函数方法应用于描述LPG发动机缸内不同区域的温度来模拟NOx的生成,同时考虑了缸内湍流场中组份和温度场的脉动。给出了在火花点火的燃烧方式下,LPG发动机在不同曲轴转角下缸内NOx的时空分布。计算和试验结果吻合良好。与其它PDF方法相比更趋理性,为研究和改善发动机的排放提供了参考。     

Analysis on maneuvering motion characteristics of submarine under static moment in vertical plane北大核心CSCD

[Objectives]Aiming at the problem of poor depth-changing ability of the stern rudder of submarine at low speed, and the problem of reversing the movement trend is difficult when the stern rudder is stuck and encountering abrupt changes of seawater density in the vertical steering maneuver. This paper conducts the mechanism research of static moment maneuver. [Methods]First, it is proved through theoretical analysis that the static moment maneuver can eliminate the reversed velocity phenomenon of the stern rudder. Then, the surfacing process under the static moment maneuver and the rudder hydrodynamic control is numerically simulated. [Results]The simulation results show that the static moment maneuver can make the submarine maintain good vertical plane maneuverability at low speed, eliminate the reversed velocity phenomenon of the stern rudder, and avoid excessive trim angle of the submarine at high speed. At the same time, the recovery effect of the two emergency situations of rudder jamming and falling deep has been improved. [Conclusions]The static moment maneuver is beneficial to the maneuverability and safety of the submarine. The research in this article can provide a reference for the maneuverability design of submarine. © 2023 The Author(s).     

面向刚度设计的 GFRP 和 VRB/GFRP 混合层合板应变能密度分布研究

针对 VRB/GFRP混合结构刚度优化设计复杂而耗时这一问题，利用有限元法分析了 GFRP铺层角度和铺层数量、VRB厚度分布形式对两种层合板刚度特性及各组分应变能密度分布的影响规律。研究结果表明，应变能密度越小能表征更好的刚度性能；抗弯与抗凹工况下，采用# （0/90） 铺层角度、增加 GFRP铺层数量以及 VRB采用 0.9-1.8-0.9 mm 的厚度分布形式时，VRB/GFRP层合板各组分的应变能密度分布更加均匀，从而获得更好的刚度性能。     

湘江大源渡船闸引航道异重流淤积分析

根据异重流运动的特点，从水体重率沿程变化的机理出发，推导出异重流计算公式，并用于大源渡船闸引航道淤积计算。通过类比分析，其淤积量分布与实测资料基本一致。