A novel high resolution model without open boundary conditions applied to the China Seas: first investigation on tides

We developed a Global Ocean Circulation and Tide Model （GOCTM） with coarse grids in the open deep ocean degrading ‘smoothly’ into the highly resolved China Seas （CS） of refined grids to study the tides and circulation there.GOCTM is based on the framework of the Finite Volume approach for better mass conservation through improved transports across the discrete individual control volume.It also takes a full advantage of the geometric flexibility of unstructured mesh using a realistic global topography including the Arctic Ocean.The CS are given a special focus by refining the unstructured grids,but they are embedded into global domain naturally.Furthermore,GOCTM not only successfully avoids the treatment of the open boundaries,but also optimizes the trade-off between computational cost and model accuracy.Meanwhile,GOCTM is driven by the astronomical tide-generating potential and the secondary tide-generating potential directly,together with the wind stress and heat flux.GOCTM succeeds in reproducing the global eight principal tidal harmonic constants.Particularly,the simulated tidal results in the CS are improved compared to some other regional models with the discrepancy of 3.9 cm for M 2 tide.This idea of GOCTM can also be referred for other regional ocean study.

ON THE EXACT HAUSDORFF MEASURE OF A CLASS OF SELF-SIMILAR SETS SATISFYING OPEN SET CONDITION

In this paper, we provide a new effective method for computing the exact value of Hausdorff measures of a class of self-similar sets satisfying the open set condition （OSC）. As applications, we discuss a self-similar Cantor set satisfying OSC and give a simple method for computing its exact Hausdorff measure.

Ocean Model Open Boundary Conditions with Volume, Heat and Salinity Conservation Constraints

Open boundary conditions （OBCs） for a regional ocean model that can be integrated stably over a long timeframe, as well as satisfy the volume, heat and salinity conservation constraints, were developed. First, the idea that the inward and outward flux information can be treated separately in the OBCs was adopted. Second, in order to maintain the property that the volume, heat and salinity remains conserved in the simulation domain, conservation constraints were added to the OBCs, and an inverse method utilized to solve the constraint equations. Ideal experiments were designed to investigate the conservation property, and the OBCs were found to work efficiently to maintain the volume, heat and salinity conservation. It was found that simulations were comparable to observations when the OBCs were applied to a regional ocean model.

AN ADAPTIVE OPEN BOUNDARY CONDITION

A significant improvement of the open boundary condition which was originally studied by Engquist and Majda is given.The method given here is applicable without limitation of the angle between the direction of the incident wave and the normal to the boundary.It also improves the precision of the method from order one to two.The test examples show that this method is much better than the method mentioned above.

The High Precision Open Boundary Conditions Designed for Transient Waves

In Rels. [2-4] there is an Adaptive. Open Boundary Condition (AOBC) designed for transient waves which overcomes the limitation of the existing Open BoundaryCondition (OBC) and can be used for the cases of waves with arbitrary incidentangles. In this article a new family of high order AOBC has been designed on the basisof the above mentioned AOBC with the first order.In comparison with all other OBC with the same order, this new family of AOBC has the highest precision.

面向主给水系统的流动调整器整流性能数值研究

针对某核电站主给水系统低负荷时文丘里流量计测值虚高所提出的流场改善需求,利用计算流体力学方法结合SST k–ω湍流模型,研究安装流动调整器时的流场特征和整流性能。首先分别对流场未安装和安装栅格(AMCA)调整器及不同结构参数的孔板调整器进行三维建模和计算,获得不同调整器对流场速度、压力、流场均匀度及流量计流出系数的影响,对比不同调整器对旁路支管所致流速畸变的整流性能,并确定选用孔板调整器的构型。其次改变调整器安装位置,对比安装位置对流场速度分布、阻力损失、均匀度改善及流量计流出系数的影响。三是针对满负荷大流量工况,将调整器与不同开度的主调节阀耦合建模,计算调整器所致额外压力损失,分析阀门开度与整流器压力损失的关系。获得的调整器构型和安装位置等参数的影响规律可为核电站主给水系统解决同类问题时的流动调整器选型和安装提供参考。

矿井救生舱空调CO_2在毛细管内的节流仿真

节流降温装置是矿井救生舱CO2开式空调中关键的部件之一。采用毛细管进行节流降温,首先针对CO2节流过程进行热力学分析,然后建立两相区及气相区的节流数学模型并进行仿真计算。计算结果表明:制冷量越大,所需毛细管长度越长;在相同制冷量条件下,毛细管内径越大,所需毛细管长度越长;初始温度越高,可利用的焓差越小,且节流所需毛细管长度越长。最后针对制冷量分别为2kW和3kW的系统进行毛细管节流降温设计。

开放式兔舍水空调技术夏季降温效果

夏季高温严重制约中国兔业生产,蒸发降温方式在高温高湿的家兔主产区难以发挥有效作用。该研究以地下水为循环介质的非蒸发降温系统水空调用于外围护隔热性能不佳的开放式繁殖母兔舍,通过管道实现点对点局部降温,研究其降温效果。试验期内,试验舍兔笼内14:00平均气温较对照舍低2.5～3.3℃(P<0.05),相对湿度高8%。试验舍风速控制在0.7～1.4m/s,温湿指数控制在25.5～29.0,较对照舍降低1.4～2.9(P<0.01),综合热环境状况较对照舍明显改善。舍内母兔在午后高温时段热性喘息有所缓解。结果表明,在开放式兔舍中夏季采用水空调系统进行局部降温,较为适合中国当前家兔养殖模式,有助于缓解夏季妊娠或哺乳母兔的热应激。

增程式电动汽车增程器的控制策略研究

针对增程式电动汽车的动力分配问题,以提高续驶里程为设计目标,提出了一种考虑空调/暖风开启的多工作点控制策略,采用粒子群优化算法优化发动机工作点,并通过Matlab/Simulink和Advisor仿真平台,在NEDC工况下对优化后的多工作点策略进行了仿真验证。结果表明:优化后的多工作点控制策略符合设计要求,可提高续驶里程,该控制策略相较于忽略空调/暖风开启的三工作点控制策略,其汽车能量利用率有明显的提高。

Entanglement in an anisotropic spin-1 Heisenberg chain

The entanglement in an anisotropic spin-1 Heisenberg chain with a uniform magnetic field is investigated. The ground-state entanglement will undergo two different kinds of transitions when the anisotropy △ and the amplitude of the magnetic field B are varied. The thermal entanglement of the nearest neighbour always declines when B increases no matter what the value of the anisotropy is. It is very interesting to note that the entanglement of the next-nearest neighbour can increase to a maximum at a certain magnetic field. Regardless of the boundary condition, the nearestneighbour entanglement always decreases and approaches to a constant value when the size of the system is very large. The constant value of open boundary condition is much larger than that of periodic boundary condition.

2-D CHARACTERISTICS LIKE MODEL AND OPEN BOUNDARY CONDITION FOR UNSTEADY OPEN CHANNEL FLOW MODELING

A characteristic like model is presented to calculate the two dimensional flow in open channels with finite or infinite dimensions. The comparisons between the computational results and experimental data show the model to be robust in simulating two dimensional unsteady flows. The comparisons also show the effectiveness of the open boundary condition in simulation of wave propagation process in an infinite domain with computational domain of finite dimension.

ANALYTIC METHOD FOR INVERSING THE OPEN BOUNDARY CONDITIONS IN A SEMI-CLOSED SEA AREA—CASE I FOR INVERSING THE TIDAL LEVELS AT OPEN BOUNDARY

In this paper, a computational case was employed to describe thecomputational procedure for inversing the tidal level open boundary conditions using an analyticmethod. The area for finding the solution is a circular area with a circular arc with the openingangle 60°-being the open boundary and the other circular arc being the solid wall boundary.Proceeding from the reestablished elliptic partial differential equation satisfied by the tidallevel function, the extended spectrum method was used to derive the general solution of the equationfor the sea of constant depth, and the impermeable solid wall condition (the second class boundarycondition) and the adequately specified open boundary conditions were then applied to determine theundetermined coefficients of the general solution, thus obtaining the tidal level distributionfunction. In this way, both the first and second class boundary values at the solid wall boundarywere obtained. With the above boundary values as the boundary conditions, the tidal level values atthe open boundary were then inversed by means of the general solution of tidal wave equation. Thevalidity of inversion method could be verified by comparing the inversed tidal level distributionswith the originally specified open boundary values.

A Negative Answer to a Conjecture on Upper Convex Density

Let E be a self-similar set satisfying the open set condition. Professor Xu conjectures in his doctoral degree thesis that if H^8（E） 〈｜E｜^8, then for any x ∈ E, the inequality ^-D^3C（E,x）〉H^8（E）/｜E｜^8holds, where 3 = dimH（E）. The above conjecture is negatively answered in this＇paper.

基于工业机器人的压缩机开盖设计

采用标准工业机器人和PLC控制系统来实现全自动化的空调压缩机开盖功能,机器人和PLC控制系统采用PROFINET总线进行通信以及数据交换,该系统通过工业机器人的检测探头对压缩机外壳的焊接处进行一次360°的信息采集,将其外壳信息进行记录,控制刀具按照已采集到的外壳轨迹信息进行一次360°的走位,即可实现压缩机的开盖过程,再此过程中,PLC控制系统主要完成以下工作:取料、自动换取探头、刀具、夹具、开盖、送入运料小车等动作。通过机器人和PLC的完美配合,提高了开盖设备的自动化程度和企业运作效率。

STUDY ON THE ADJOINT METHOD IN DATA ASSIMILATION AND THE RELATED PROBLEMS

It is not reasonable that one can only use the adjoint of model in data assimilation. The simulated numerical experiment shows that for the tidal model, the result of the adjoint of equation is almost the same as that of the adjoint of model: the averaged absolute difference of the amplitude between observations and simulation is less than 5.0 cm and that of the phase-lag is less than 5.0°. The results are both in good agreement with the observed M2 tide in the Bohai Sea and the Yellow Sea. For comparison, the traditional methods also have been used to simulate M2 tide in the Bohai Sea and the Yellow Sea. The initial guess values of the boundary conditions are given first, and then are adjusted to acquire the simulated results that are as close as possible to the observations. As the boundary conditions contain 72 values, which should be adjusted and how to adjust them can only be partially solved by adjusting them many times. The satisfied results are hard to acquire even gigantic efforts are done. Here, the automation of the treatment of the open boundary conditions is realized. The method is unique and superior to the traditional methods. It is emphasized that if the adjoint of equation is used, tedious and complicated mathematical deduction can be avoided. Therefore the adjoint of equation should attract much attention.

An SPH wave-current flume using open boundary conditions

In this paper, a novel numerical wave-current flume is implemented based on the Smoothed Particle Hydrodynamics (SPH) method. The proposed flume is more stable and computationally efficient than conventional ones because it cancels wave paddles or sponge layers while using a non-reflective open boundary condition to simultaneously generate and absorb waves and currents. Numerical tests of nonlinear regular waves interacting with steady currents in the same/opposite directions indicate that the wave-current interactions mainly affect the horizontal velocity distributions in the water body, with little influence on the vertical movements. Water particle trajectories are stretched, and the mass transportation effects are enhanced when the waves and currents are in the same direction. When the directions are opposed, the trajectories, as well as the mass transportation, are compressed, suppressed and even reversed. The applications of solitary wave-current interaction over a submerged bump further show that the relative direction between the wave and the current has remarkable influence on the wave breaking pattern over an underwater obstacle.

ON THE HIGH PRECISION ADAPTIVE OPEN BOUNDARY CONDITIONS FOR TRANSIENT WAVES

The adaptive open boundary conditions (AOBC) designed by Chen and Zou for transient waves overcome the limitation of the existing open boundary conditions (OBC) and can be used for the cases of waves with arbitrary incident angles. In this paper a new family of AOBC has been designed on the basis of the AOBC with first order mentioned above. In comparing with all other OBC with the same order, this new family of AOBC has the highest precision. It can be generalized into 3D problems without difficulty and its forms in different curvilinear coordinate systems can be got very easily. The distinguished advantages above mentioned of the AOBC will be discussed in this paper.

A Note on Upper Convex Density

For a self-similar set E satisfying the open set condition,upper convex density is an important concept for the computation of its Hausdorff measure,and it is well known that the set of relative interior points with upper convex density 1 has a full Hausdorff measure.But whether the upper convex densities of E at all the relative interior points are equal to 1？ In other words,whether there exists a relative interior point of E such that the upper convex density of E at this point is less than 1？ In this paper,the authors construct a self-similar set satisfying the open set condition,which has a relative interior point with upper convex density less than 1.Thereby,the above problem is sufficiently answered.

空调器开放负载智能设备研制及应用

为了优化空调器测试工艺,提高智能装备的开发及维护效率,提出一种空调器开放负载的控制方式,实现主动、自由控制所有负载,监测负载性能,并研制智能故障分析、测试等设备,保障产品质量,提高生产产能,降低售后维修率。