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The method uses a vacuum to withdraw a stream of gasliquid dispersion from the bubble or foam column through a capillary tube with a funnelshaped inlet.


Pulseshaped inlet boundary conditions were assigned to simulate the dynamic tire loading on the asphalt pavements.


To sample aerosols, the air inlet valve is opened and air is drawn into the 3603 sandwichshaped inlet.




 The paper presents the results of measurement of the static pressure and swirl in the flow through an Sshaped duct of typical air intake proportions mounted in a wind tunnel and tested at different incidence.In order to reduce the magnitude of swirl at high incidence,two methods have been studiedone,to change the distribution of pressures by means of a spoiler and two,to reenergize the separated flow with an inflow of free stream air through auxiliary inlets.The results show a small degree of swirl at low... The paper presents the results of measurement of the static pressure and swirl in the flow through an Sshaped duct of typical air intake proportions mounted in a wind tunnel and tested at different incidence.In order to reduce the magnitude of swirl at high incidence,two methods have been studiedone,to change the distribution of pressures by means of a spoiler and two,to reenergize the separated flow with an inflow of free stream air through auxiliary inlets.The results show a small degree of swirl at low incidence which takes the classical pattern of two contrarotating flows,and a large degree of swirl at high incidence,in the form of a single rotating flow.Of the antiswirl devices,the spoiler is the more powerful and can be sized either to reverse the swirl direction or to eliminate the swirl completely.A parameter of swirl coefficient,SC60,has been suggested,Values of SC60 at 30°incidence are 0.188 for the duct as designed,0.068 for the arrangement with auxiliary inflow and0.039 with a spoiler of width 0.15 times throat width.The various arrangements tested,together with results of an earlier study,shed useful light on the general nature of swirl in an Sductp its method of generation and its final form and magnitude.  本文给出了具有典型飞机进气道比例的S形管道在不同攻角下,压力分布和旋流的实验结果。为了减小大攻角下的旋流,研究了两种方法:一是通过扰流板改变管道内气流的压力分布,二是通过辅助进气门引入自由流空气,向分离流补充能量。结果表明,在低攻角下旋流很弱并呈现为典型的反向旋转对涡二次流动,而在高攻角下则为一个很强的单涡旋转流动。至于反旋流措施,扰流板的效果最好,通过变化其尺寸不仅能改变旋流方向,而且还可完全消除旋流。本文建议用一个旋流系数,SC_(60),来描述名义发动机进口处的旋流。其值对原设计模型在30°攻角时为0.188,而通过辅助进气门引入自由流空气向分离流补充能量后为0.068,当采用一个0.15倍喉道宽度的扰流板时,旋流系数变为0.039。本研究使S形进气道中旋流的产生、发展和性质得到进一步的认识。  A mixed finite difference method for calculating the external and internal transonic flow field around a sshaped inlet is presented. The equation of the full velocity potential in cartesian or cylindrical coordinates is used as the governing equation. As the method used for the present analysis separates coordinate system and the geometry, the mesh points may not lie on the body surface. The boundary Condition is satisfied by the mesh points which are situated in the vicinity of the wall. An improved analytical... A mixed finite difference method for calculating the external and internal transonic flow field around a sshaped inlet is presented. The equation of the full velocity potential in cartesian or cylindrical coordinates is used as the governing equation. As the method used for the present analysis separates coordinate system and the geometry, the mesh points may not lie on the body surface. The boundary Condition is satisfied by the mesh points which are situated in the vicinity of the wall. An improved analytical continuation method is developed to treat the boundary condition at solid face. A linear underrelaxation procedure is used in calculation. The relaxation process is marched forward axially from one part to another in sequential order. Calculation is repeated until the. change in velocity potential between relaxation sweeps is less than a preassigned value and the conservation of mass flow between cross sections in inlet is reached.Computations have been made for a sshaped inlet with free stream Mach number M=0.8 at different angles of attack and at angle of yaw. Computed results are compared with those computed by perturbation, method and with experimental results. Such a comparison shows that the present method is promising.  提出了一种计算跨音速S形进气道内外流场的混合差分方法.该法从速势方程出发,利用直角和圆柱坐标系、不旋转的混合差分格式以及边界的解析延拓处理,建立了流场内各网格点的差分方程,并用线松弛法进行统一迭代.计算了一个S形进气道在来流马赫数为0.8以及不同攻角状态下的内外流场,并将计算结果与摄动法计算结果以及实验值进行了比较.  Sinc early 1970's the Sshaped inlet is increasingly widely used in flight vehicles.The flow through the Sshaped inlet is a threedimensional viscous flow.In the case of the computation for the threedimensional viscous flow with the viseousinviscid iteration,the computing time and capacity required for the inviscid flow when employing conventional methods(such as FDM,etc.)is even greater than for the boundary layer itself [12] .Furthermore,the calculation of threedimensional boundary layer is very complex... Sinc early 1970's the Sshaped inlet is increasingly widely used in flight vehicles.The flow through the Sshaped inlet is a threedimensional viscous flow.In the case of the computation for the threedimensional viscous flow with the viseousinviscid iteration,the computing time and capacity required for the inviscid flow when employing conventional methods(such as FDM,etc.)is even greater than for the boundary layer itself [12] .Furthermore,the calculation of threedimensional boundary layer is very complex and difficult [13] so that to date no simple and practical method and computer program,to the best of the author's knowledge,have ever been presented.The purpose of this paper is to develop an engineering method of prediction for the three dimensional boundary layer in the Sshaped inlet.This method is characterized by its simplicity and rapidity of calculation,so that the calculation can be performed on the microcomputer IBMPC.This method will be suitable for rapidly assessing the aerodynamic quality of the inlet during its configuration design and the modified design.This method can save much time and reduce cost in the development of a new flight vechicle. The main contributions of this paper are as follows:  本文提供了一种计算 S 形进气道内三元附面层的工程方法,它先用摄动法计算物面势流流线及对应的势流速度分布,然后,采用物面流线正交曲线坐标系,沿流线以轴对称模拟的方法计算三元附面层,对几何形状为面对称的进气道,还可用等角度线近似地代替流线,使计算进一步简化。本方法具有简单快速的特点。用本方法计算了两种几何形状不同的进气道在不同来流马赫数及流量系数下的附面层,得到了管内附面层参数及分离区分布情况,计算值与实验结果基本符合。本方法在型号选形设计阶段可快速鉴定进气道的气动品质,从而可加快研制进度和节约经费。   << 更多相关文摘 
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