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Inverse speed is a reversible maneuver.It is a characteristic of underwater vehicle at low speed.Maneuverability in the vertical plane at a speed lower than inverse speed is different from one at higher speed.In the process of underwater working for observation,AUV's cruise speed is always low.Therefore,the research on inverse speed is important to AUV's maneuverability.The mechanism of inverse speed was analyzed,and then the steady pitching equation was derived.The parameter expression of track angle in vertical plane was deduced.Furthermore,the formula to calculate the inverse speed was obtained.The typical inverse speed phenomenon of the flat body and the revolving body was analyzed.Then the conclusion depicts that,for a particular AUV with flat body,its inverse speed is lower than that of revolving body.After all the calculation and the analysis,a series of special experiments of inverse speed were carried out in the simulation program,in the tank and in the sea trial. 相似文献
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结合我国北斗全球卫星导航系统BDS的建设需求,对现阶段北斗区域服务系统BD2和未来BDS以及多星座GNSS组合的定位性能进行分析是十分必要的。针对BD2,通过仿真和实测数据两种方法分别对BD2,GPS/BD2和GPS/BD2/GLONASS进行了分析,分析结果表明BD2完全满足北斗公开服务性能规范中的定位性能要求,而且随着星座数的增加,定位性能逐渐增强,加入GLONASS后对高纬度区域定位性能的改善尤为明显。针对BDS,主要通过仿真的方法,对BDS和未来四大全球导航系统组合进行了分析,分析结果表明,未来BDS仍然对亚太地区的定位性能有明显的增强效果,而且未来BDS在其他地区的位置精度因子(PDOP)平均值也达到1.2~1.6,此外,未来四大导航系统组合对极区的定位性能改善较为明显。 相似文献
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介绍了该水电站的工程概况和通风空调系统设计特点。空调设计中,在确定室外空气计算参数时对乌东德气象参数进行了修正;根据水电站所处地形,提高了水电站取风点高程,从而减少了新风负荷;对厂房内气流组织进行了分析,水电站选择全面通风(未经降温除湿处理)与局部区域现地降温冷却相结合的方式,以满足厂内降温和通风换气要求。 相似文献
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根据某水电站大坝廊道热湿环境及廊道布置特点,设计几种通风模式,利用CFD分析不同通风模式的可行性和节能性。结果表明:大坝廊道自然通风与厂房新风系统相结合,能够改善廊道空气质量,降低厂房通风空调系统的新风温度;利用大坝楼梯间加压送风系统可以增大进入厂房的新风风量;在自然通风管总横截面积一定的前提下,合理减少通风管数量、增大管与连通通道的距离,可以增加廊道的等效节能冷量。 相似文献