thickness n. 1.厚;粗;厚度;粗大。 2.濃度,濃厚,黏稠。 3.密度;稠密。 4.模糊不清,多煙霧,混濁。 5.愚笨;遲鈍。 6.最厚[粗,密,濃]處。 7.(有一定厚度的東西的)一張,一層。 8.親密。 coal seams of less thickness than five feet 厚度不及五英尺的煤層。 the thickness of population in New York 紐約的人口密度。 wood of different thickness 厚度不同的木頭。 five thicknesses of cardboard 五層紙板。
displacement n. 1.轉(zhuǎn)位,移動;取代,置換;(人的)流離失所。 2.撤換,免職。 3.【機械工程】(活塞)排氣量;【航海】排水量〔一般指軍艦的排水量;商船的排水量一般用 gross [net] ton(nage)〕。 4.【化學(xué)】置換(作用),取代(作用);【物理學(xué)】位移;【醫(yī)學(xué)】移位;【生物學(xué)】替位;【藥學(xué)】濾過;【地質(zhì)學(xué);地理學(xué)】(斷層)移動。 displacement nitration process 【化學(xué)】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 主要研究內(nèi)容和成果如下:對航行器繞流流場進行分析,深入研究了阻力和流噪聲產(chǎn)生機理,建立了阻力系數(shù)和自噪聲的評估數(shù)值計算模型;采用物面分布源匯法和邊界層動量積分法對繞流流場的流體動力參數(shù)進行計算,改進了轉(zhuǎn)捩區(qū)長度和邊界層位移厚度的計算,應(yīng)用于航行器頭部駐點自噪聲的計算;最后設(shè)計了阻力系數(shù)和自噪聲數(shù)值計算程序模塊。
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 本文分別用守屋的保角變換法和基于源匯渦分布的面元法,建立了計算槳葉表面壓力分布的數(shù)學(xué)模型;應(yīng)用納維-斯托克方程的薄層近似理論模式和有限差分?jǐn)?shù)值方法,建立了計算機翼表面邊界層內(nèi)部流動的數(shù)學(xué)模型;應(yīng)用槳葉表面邊界層內(nèi)部粘性流動和外部勢流流動在邊界上的匹配算法,建立了槳葉表面二相流流動的計算方法和相應(yīng)的計算機程序。