首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
沿海渔船的船型瘦小,对于动稳性的变化较为敏感,船体破损后失稳会产生严重的危害,因而近海作业的沿海渔船破舱稳性研究有比较实际的应用价值.运用CFD软件STAR-CCM+,对一艘28.8 m长、作业区域为渤海的养殖看护船,进行横浪条件下瞬时非对称进水过程的时域模拟,得到该船破舱进水过程中船舶的六自由度变化以及压力分布.对比该船在3种海况下破损后的物理行为发现,非对称舱进水会在波浪作用下带动船舶产生不同程度的艏摇运动,促使破损船由横波运动向纵波运动转变,基于破损后的运动响应,可以对渔船的舱室分布及对破舱事故后的操纵及减损提供参考意见.  相似文献   

2.
为研究船舱破损进水对船舶横摇运动的影响,建立了破舱进水船舶在规则横浪中的横摇运动微分方程,将进舱水晃荡产生的动力矩作为作用于船舶的外力矩.利用FLOW-3D对进舱水产生的动力矩进行仿真模拟计算,利用Matlab编程对破舱进水的横摇运动方程求解,计算分析破舱进水晃荡对船舶横摇运动的影响.以一艘拖轮为例,用时域法对不同波浪频率下的横摇运动响应进行计算,对比分析了规则横浪中的完整和破舱状态船舶的横摇运动响应特性.结果表明,在船舶大幅运动时,进舱水液面会成波浪状,产生翻卷和破碎,引起较大的合外力矩,使横摇运动幅值增大,危及船舶安全.  相似文献   

3.
提供出船舶破损第三类进水舱浮态快速计算方法。同时利于自由流通对稳性的影响,理论分析和推导出破舱稳性公式。并参照国际海事组织有关文件,结合国际惯例,对破舱稳性衡准的有关问题进行了探讨。同时给出了船舶破损后,危险程度的快速预报方法。  相似文献   

4.
船舶破舱进水速度与时间的计算   总被引:4,自引:2,他引:4  
在恶劣的航海条件下,船舶的碰撞,搁浅,触礁等恶性事故的发生都将导致船舶的破舱进水,船舶破舱进水后进水量的大小及所需的时间是驾驶员一直关注的问题,为此建立了船舶破舱暖时进水速度的计算模型,通过编程对船舶不同的破口大小及其位置进行实船计算,求出了船舶下沉,纵倾达到新的平衡水浅甚至沉没所需的时间,为驾驶员迅速判断船舶的破舱安全性,并做出正确求船决策提供理论依据。  相似文献   

5.
船舶破舱危险状态及施救能力   总被引:1,自引:1,他引:0  
建立船舶破舱瞬时进水速度的计算模型,通过程序计算得到船舶破舱浮态、稳性、强度与进水时间的函数关系.提出船舶破舱危险状态的概念,确定船舶危险状态所对应的进水速度,通过将此船舶破舱进水速度与船舶排水设备能力的比较确定船舶的施救能力.分析船舶的施救机理,确定船舶施救的可行性,提供相应的施救决策.该决策为船员迅速判断出船舶破损的安全状态并得到正确的施救方案提供理论依据。  相似文献   

6.
船舶破舱进水及其影响因素   总被引:1,自引:0,他引:1  
为了在船舶因发生碰撞、触礁、搁浅等海上事故导致破舱进水问题对事故船舶的抗沉性快速地作出适当评价依据流体力学基本原理建立了船舶破舱瞬时进水速度及进水量的数学模型,分析了破损参数及装载条件对破舱进水参数的影响.通过编程对船舶在不同破损及装载条件进行了实际计算,得出了相应的破舱进水参数。从而为船舶驾驶人员作出正确施救对策提供可靠依据,对保证船舶安全具有重要意义.  相似文献   

7.
船舶设计初期进行破舱稳性的计算分析对船舶安全至关重要,研究概率破舱稳性是其核心内容。SOLAS 2009为一种基于概率性计算破舱稳性的方法,可较为准确地评估船舶各个舱室的浸水风险概率。基于SOLAS 2009要求,采用maxsurf搭建数值仿真模型、划分舱室,按照不同舱室破损的组合求解达到的分舱指数。评估船舶的概率破舱稳性达到了公约要求,但部分舱室划分不合理,最后依据计算结果对不合理舱室进行简单处理,提高船舶的抗沉性,实现了利用公约计算、分析船舶舱室划分合理性的可行性研究。  相似文献   

8.
研究了驳船液体舱室中自由液面的分布以及舱容率对船舶浮态和稳性的影响,计算了船舶在风载荷作用下的稳性衡准数,并对船舶破舱稳性进行了分析,分析结果可为驳船实浮拒航提供参考。  相似文献   

9.
为提高散货船配载仪中破舱稳性的计算精度,基于船舶三维设计数据进行破舱稳性计算.首先沿船长方向对船体的三维设计模型进行切片,得到船体的横剖面型值数据;然后通过等距偏移模拟船体外板厚度,得到船舶外板数据;最后分别利用最小功法和静平衡法计算破损船舶各个横倾角度的复原力臂.以38 300t散货船"RUI AN CHENG"为例,对3个典型载况进行了破舱稳性计算.计算结果表明:与NAPA计算值相比,静平衡法的计算结果具有较高精度,满足主流船级社的精度要求,而最小功法的计算结果则有较大误差.同时,静平衡法不仅适用于散货船配载仪的破舱稳性计算,对液货船、集装箱船等的配载仪的开发也具有一定参考价值.  相似文献   

10.
货船概率破舱稳性计算及对分舱的影响   总被引:4,自引:0,他引:4  
对船舶破舱稳性的概率计算方法作了计算分析,研究了计算中需注意的问题,分析了影响分舱指数A的主要因素和提高分舱指数A的方向及措施.并以计算实例进行验证和说明.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

19.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

20.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号