流回

The main work and the originality points of this dissertation could be concluded as the following parts:(1) To analyze systematically the mathematical model of LES of air flow in great space, under the case of isothermal and non-isothermal, as well as the combined action of buoyancy and strain. Some basic problems are studied about the LES application into airflow simulation of great space, such as boundary conditions, spatial difference scheme and time advancing scheme, time step etc., which creates the basis for the LES application to indoor airflow simulation.(2) Both the instantaneous and time averaged flow field of great space with multiple jets under isothermal and non-isothermal cases are explored with large eddy simulation method, and also discussed the dynamic characteristics and the law of fluidflow in the great space.(3) Based on the results of LES of the great space and the Fanger thermal comfort indexes, it is brought forward the concept of the series of dynamic thermal comfort evaluating indexes, which could be divided into thermal comfort index with time averaged properties PD, PPD, PMV, thermal comfort index with instantaneous properties IPD, IPPD, IPMV, and time averaged thermal comfort indexes TAPD, TAPPD, TAPMV, and transient situations time averaged thermal comfort indexes TTAPD, TTAPPD, TTAPMV. The differences among them and the calculation methods are discussed, and the four kinds of indexes are calculated with the thermal comfort index PD as an example.(4) Based on the LES results it is discussed the hot air stratification phenomena in air-conditioned buildings in the case with air supply and return registers on the ceiling and the case on the sidewall. The fundamentals of the hot air stratification are studied and the relations of estimating hot air stratification are brought forward.(5) With the advanced apparatus such as hot wire film anemometer IFA300 and laser particle field anemoscope, corresponding model test and site measurements have been done, which are compared with the simulation results and LES is proved a very promising method in air flow simulation indoor.

本文主要工作既创新点体现在以下几个方面：(1)系统分析了等温、非等温和考虑剪切力与浮升力综合作用的高大空间大涡模拟数学模型，并研究了高大空间大涡模拟在室内气流仿真应用中的一些基本问题，如边界条件、空间离散格式和时间推进格式、时间步长选择等问题，为大涡模拟在室内气流计算中的广泛应用打下了基础；(2)首次用大涡模拟方法研究了高雷诺数下高大空间多射流在等温、非等温情况下的瞬时流场和时均流场分布，并探讨了多射流流场的动态特性和流动规律；(3)基于大涡模拟的动态仿真结果和Fanger的热舒适指标，首次系统地提出了动态热舒适评价指标体系的概念：即基于时间平均参数的热舒适指标PD、PPD、PMV；基于瞬时参数的瞬时热指标IPD、IPPD、IPMV；基于时间平均热舒适指标TAPD、TAPPD、TAPMV；以及沿行动迹线的时间平均热舒适指标TTAPD、TTAPPD、TTAPMV，并分析了四类热舒适指标的差异性和计算方法，还以PD值为例对四类指标分别进行了计算；(4)基于数十种工况下空调房间大涡模拟的结果，研究了空调建筑上送上回和侧送侧回两种情况下热分层现象，并探讨了热分层的基本规律，首次提出了避免热分层现象的判断公式；(5)在暖通空调领域，首次使用IFA300热线风速仪、激光粒子速度场仪等先进设备，完成了与大涡模拟相对应的模型试验，并把实测结果与仿真结果进行了对比，说明LES在室内气流仿真方面是一种很有前景的方法。

Ulcerative colitis may be associated with backwash ileitis that results in dilatation of the terminal ileum with a gaping ileocecal valve and, at times, a shaggy thin wall.

溃疡性结肠炎也许会伴随回肠返流，导致回肠末端扩张及张口状回盲瓣，以及肠壁毛糙变薄。

With import pressure relief valves, pilot vavel disc role in the fluid pressure Fx attendant increase, when more than equal to Fx Pt2, pilot valves valves mouth opened, the pressure relief valves to import oil by damping hole, Pilot valves valves mouth overflow relief valves to export, and then back to the fuel tank.

随着溢流阀的进口压力增大，作用在先导阀芯上的液压力Fx随之增大，当Fx大于等于Pt2时，先导阀阀口开启，溢流阀的进口压力油经阻尼孔、先导阀阀口溢流到溢流阀的出口，然后回油箱。

With import pressure relief valves, pilot vavel disc role in the fluid pressure Fx attendant increase, when more than equal to Fx Pt2, pilot valvesvalves mouth opened, the pressure relief valves to import oil by damping hole, Pilot valves valves mouth overflow relief valves to export, and then back to the fuel tank.

随着溢流阀的进口压力增大，作用在先导阀芯上的液压力Fx随之增大，当Fx大于等于Pt2时，先导阀阀口开启，溢流阀的进口压力油经阻尼孔、先导阀阀口溢流到溢流阀的出口，然后回油箱。

Fishing boats, however, love this territory, for fishes who were born in the Arctic and were therefore accustomed to the cold temperat- ure of the Labrador Current feel very unhappy in the tepid water of the Gulf Stream.

但是渔船却很喜欢拉布拉多流的寒冷，而不喜欢待在湾流的暖水中。因为鱼类正在缓慢地决定回北极或顺着温暖的湾流游泳时，它们往往被法国渔民的渔网所获。这些渔民的祖先在几百年前比任何人都更早地发现传说中的美洲大堤。我觉得译文在校对的眼皮底下顺利通过，其中的环节值得怀疑。

By substituting stream function into differential equation, its validity is proved in mathematics and the analytical expression of helical solitary vortex function is also obtained.

将获得的流函数回代到涡与流函数微分方程中，在数学上验证了这些流函数解的正确性。

The poor connection of all the NCU1 network controllers of your company's BA system has made it impossible to have an on-line control of the No.2 recycling pump of heat exchanger, the geothermic pump, the pump motor, the ventilation motor, the grill motor, and other equipment, and to read the feedback values of the on-spot breakdowns and conditions.

贵司BA系统NCU1网络控制器全部离线，造成热交换器2#循环泵、地热循环泵、水泵电机、通风电机、格栅电机等设备无法在线控制，不能读取现场故障、状态等反馈值。1#－5＃生活水泵、生活水泵运行时间统计、锅炉系统供回水压差、供水温度、回水温度、回水流量等数值无法显示运行状态及现场流量值数据。

It suggests that the horizontal momentum of the meso-cyclone was brought down to the surface by heavy rain. At the right edge of meso-cyclone the momentum and RIF have the same direction, the two airflows overlay together and make the wind increase, so damage wind occurred.

分析认为，弓状回波后部存在较强后部下沉入流，由于强降水的拖曳作用，将中层中气旋的水平动量带到地面，中气旋右侧动量的方向与弓状回波后部的强下沉入流方向一致，两者叠加，使地面风速加大，造成灾害性大风。

As the characters showing, the start of storm trailed off, the height of the top and the strong center of echo falling down indicates the downburst begin.

3多起下击暴流过程发生时回波顶、强回波中心高度下降，表明风暴减弱的开始是下击暴流开始形成的显著特征。

As a downstream piping system when the valve opens, reflux valve, when closed, the main medium used to prevent backflow to prevent the pump and drive motor reversal, as well as a container medium discharge; currently the most commonly used is the valve flap around the body Swing Pin rotation flap valve and the valve body along the vertical axis to move lift check valve, but the above two kinds of structures exist in the valve closed, medium speed back quickly from the largest drop to zero, inlet side of the pipe resulted in the rapid pressure rise, resulting Proportional Pressure Reducing Valves in damaging effects on the piping system of water hammer phenomenon, it is generally a diameter of valve production of 50 ~ 500 mm.

止回阀作为管道系统顺流时开启，逆流时关闭的阀门，主要用于防止介质倒流，防止泵及驱动电机反转以及容器内介质泄放；目前使用最普遍的是阀瓣围绕阀体销轴旋转的旋启式止回阀和阀瓣沿着阀体垂直中心线移动的升降式止回阀，但以上2种结构的阀门均存在关闭时介质倒流速度从最大迅速降为零，致使管道进水管一侧内压迅速升高，从而产生对管路系统有破坏作用的水锤现象，所以一般止回阀生产口径为50～500 mm。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。