thickness n. 1.厚;粗;厚度;粗大。 2.浓度,浓厚,黏稠。 3.密度;稠密。 4.模糊不清,多烟雾,混浊。 5.愚笨;迟钝。 6.最厚[粗,密,浓]处。 7.(有一定厚度的东西的)一张,一层。 8.亲密。 coal seams of less thickness than five feet 厚度不及五英尺的煤层。 the thickness of population in New York 纽约的人口密度。 wood of different thickness 厚度不同的木头。 five thicknesses of cardboard 五层纸板。
displacement n. 1.转位,移动;取代,置换;(人的)流离失所。 2.撤换,免职。 3.【机械工程】(活塞)排气量;【航海】排水量〔一般指军舰的排水量;商船的排水量一般用 gross [net] ton(nage)〕。 4.【化学】置换(作用),取代(作用);【物理学】位移;【医学】移位;【生物学】替位;【药学】滤过;【地质学;地理学】(断层)移动。 displacement nitration process 【化学】取代硝化。
In the thesis the low drag - low noise optimization of the vehicle main form design is realized , main accomplishments are as follows . researched the knowledge of drag and flow noise , the parameters of the boundary layer are calculated by the hess - smith method and boundary layer momentum integral method . the calculation of the length of transition zone and change in boundary layer displacement thickness between laminar and turbulent states in the transition is improved , then the drag coefficient and self - noise from the transition zone are calculated as the objective functions of the optimization 主要研究内容和成果如下:对航行器绕流流场进行分析,深入研究了阻力和流噪声产生机理,建立了阻力系数和自噪声的评估数值计算模型;采用物面分布源汇法和边界层动量积分法对绕流流场的流体动力参数进行计算,改进了转捩区长度和边界层位移厚度的计算,应用于航行器头部驻点自噪声的计算;最后设计了阻力系数和自噪声数值计算程序模块。
In order to predict hydrodynamic characteristics a computational system is developed including determination of the pressure distribution on a wing section by use of the conformal mapping method and panel method respectively and of the flow in boundary layer according to the thin shear layer approximation ( tsl ) for navier - stokes equation approach . the wing sections of naca4412 and naca0012 are applied to test the computational system . the numerical inspection shows that the panel method with better precision and the momentum and the displacement thickness of boundary layer can be used to complete this calculation 本文分别用守屋的保角变换法和基于源汇涡分布的面元法,建立了计算桨叶表面压力分布的数学模型;应用纳维-斯托克方程的薄层近似理论模式和有限差分数值方法,建立了计算机翼表面边界层内部流动的数学模型;应用桨叶表面边界层内部粘性流动和外部势流流动在边界上的匹配算法,建立了桨叶表面二相流流动的计算方法和相应的计算机程序。