壁面局部振动的二维管内流动分析

通过求解二维雷诺时均Navier-Stokes方程,对壁面局部振动的二维管内流场进行数值模拟,分析边界条件在不可压缩计算及可压缩计算情况下对壁面局部振动流动状态的不同影响.研究表明,在不可压缩计算情况下,总压入口条件相对于速度、质量流量入口条件限制少,壁面振动可同时影响振动壁面上、下游的流动参数.在壁面振动管道内,尽管马赫数Ma0.3,可压缩流体的流动现象是完全不同于不可压缩流体的.边界条件对于高频振动计算结果的影响比低频振动计算结果的小.因此,在模拟燃气轮机小幅高频振动叶栅的实际工程问题中,必须采用可压缩计算.在相对平缓、充分的入口段条件下,仍然可以采用常规模拟叶片绕流时的速度入口边界条件进行计算.     

航槽三维流动的数学模型

提出了一种模拟航槽内三维流动的数学模型．该模型将压力分解为动水压力与静水压力之和,由控制体积法导出三维偏微分方程的离散格式,采用Ｐａｔａｎｋａｒ和Ｓｐａｌｄｉｎｇ提出的压力校正法求解动水压力场,然后求解水位控制方程,用最新求出的水位替代压力校正法中的水位,如此循环迭代直至收敛．该模型无须采用“静水压力假定”和“刚盖假定”,能够模拟不可压缩流体含自由表面流动问题．利用该模型计算得到的挖槽内流速分布与水槽试验值吻合．此外,还计算了相当于天然情况各种水深、各种挖深比、各种挖槽底宽下挖槽内的流场．     

膜结构风致响应的分区耦合算法

采用完全隐式的分区耦合的方式,将用于计算流体流动和结构变形的软件结合起来.其中,结构和流场的几何模型分别通过有限元软件ANSYS和CFD软件建立.对流体域的模拟采用有限体积法,计算三维的、不可压缩的、湍动流动;对结构域的模拟采用有限元法,并且考虑了薄膜结构几何非线性.在每一时间步内对结构场、流体场依次求解,通过把前一个物理场的计算结果作为外荷载施加于后一个物理场来实现两个场的耦合.最后对一鞍形膜结构进行了风致响应计算,验证了这种耦合算法的可行性.     

取水池内三维流场的数值计算

本文应用不可压缩流体三维Navier—Stokes方程组求解明渠内的三维水流运动．利用k-ε双方程湍流模式计算涡粘性系数．控制方程组采用隐式差分离散，SIMPLEC程式求解．文中对矩形明渠开挖槽沟后挖槽区的流场进行了计算．所得结果与有关文献给出的测量值比较一致．作为应用，对某电厂循环供水系统中取水池内的三维流场进行了计算．计算结果可供工程界参考．     

叶栅梢部与固壁间隙流动的数值模拟

通过求解不可压缩流体RANS方程，对叶栅梢部与壁面之间的粘性流动进行数值模拟，计算模型基于Chorin的人工可压缩性方法，采用Baldwin-Lomax零方程湍流模式封闭控制方程组，针对间隙流动的特殊性，采用流场分块的方法以提高网络生成质量和计算稳定性，数值计算结构和试验数据的比较表明，该方法能够准确地模拟间隙流动。     

氢冷器回路调节阀开闭过程流场及噪声特性

为研究某核电站常规岛氢冷器回路调节阀在关闭和开启过程中的流场特性及引发的水力噪声特性，使用计算流体力学方法捕捉流场中的流动细节。通过六面体和四面体混合网格对管道和调节阀流体域进行离散，采用压力基求解器结合半隐格式求解连续性方程和动量守恒方程（N-S方程）得到压力和速度场，使用标准k-ε湍流模型对N-S方程进行封闭。阀门开闭过程由并行化用户自定义函数和动网格方法进行控制，噪声特性通过声学类比模型获得。结果表明，在调节阀的运动过程中，其内部流场具有周期性，调节阀流场水力噪声类型为典型的宽频噪声，且内部噪声水平高于调节阀下游区域约8%；调节阀整体噪声水平随开度的降低逐渐升高，且阀门内外的噪声水平差距逐渐增大。     

二维方腔流动的有限元模拟

采用了Ｔａｙｌｏｒ－Ｇａｌｅｒｋｉｎ有限元法离散Ｎ－Ｓ方程，该法保留了高阶的空间离散精度，隐含了流线迎风的耗散作用，采用了压力校正法求解流场中各原始变量，推导了压力修正Ｐｏｉｓｓｏｎ方程的有限元离散格式，最后给出了二维不可压缩方腔流动计算结果。     

油水分离旋流器内部流场的数值模拟

本用数值方法模拟了油水分离旋流器内部的流场分布。油水混合物中的水被作为流体相，油被作为颗粒相。流体相的控制方程为连续性方程、Ｎ－Ｓ方程，其中结合了修正的Ｐｒａｎｄｔｌ混合长湍流粘性模型，颗粒相的控制方程是浓度扩散方程，流体相与颗粒相之间的相对运动由代数滑移模型确定，全部控制方程用Ｐａｔａｎｋａｒ－Ｓｐａｌｄｉｎｇ的ＳＩＭＰＬＥ算法求解。计算程序取名ＣＹＣＬＯＮ，用通用形式写出，用户只要输入旋流器     

不规则区域中可压缩流动的数值模拟

将不可压缩流动的SIMPLE算法推广到可压缩流动的计算中。将二维直角坐标系和轴对称坐标系下的可压缩流动的控制方程用统一的方程式表达,在贴体网格中利用有限体积法进行离散,编制了通用的求解程序。对带有凸包的通道可压缩流动和轴对称坐标系下的马赫反射问题进行了数值模拟,得到的结果与相关文献中的结果吻合,表明了所提算法的正确有效性。     

混流泵叶轮的正反问题迭代法设计及流动分析

提出了用正反问题迭代法设计混流泵叶轮的新方法。该方法能够有效地弥补传统方法设计叶片时轴面流动的计算仅满足流体连续方程的缺陷,同时考虑了叶片形状对轴面流场计算的影响。通过两类相对流面迭代求解流体连续方程与运动方程,完成设计叶轮的正问题计算。采用逐点积分法进行叶片骨线绘型,在轴面上加厚叶片,在保角变换平面内修圆叶片头尾部,完成反问题设计。正反问题迭代计算直至收敛,最终完成混流泵叶轮的设计。采用SIMPLEC算法,通过求解Navier-Stokes方程和RNGk-ε湍流模型方程,模拟了混流泵叶轮内的三维流场,获得了叶轮内的速度与压力分布。结果表明:正反问题迭代方法设计的叶片对于水流的控制能力增强,叶轮内部流动稳定,压力分布均匀,具有更优的水力性能。     

Markedness and its Interpretation in Language Use

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

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.     

Features of Women's language

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

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.     

Design and analysis of generic LBS application developing platform

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.     

橡胶颗粒沥青混合料低温抗裂性试验研究

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

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.     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.