laminar drag 中文意思是什麼
laminar drag
解釋
層流中的阻力-
The effect of reynolds number on rudder hydrodynamic performance is also analyzed. up to the stall angle the computed lift and drag agree well with measurements and other author ' s calculations, whereas stall angle, lift and drag beyond the stall angle are slightly under - predicted. the solver is used to investigate laminar and turbulent separated flows around a 6 : 1 prolate spheroid at high incidence angles and their effects on hydrodynamic forces
應用所開發的求解器，以naca0015翼型舵為算例計算了船舵在不同雷諾武漢理三;大學博士學位論文數下大舵角范圍內的三維粘性流場及水動力，成功地預報了舵的失速角和最大升力，並初步探討了雷諾數對舵水動力的影響;計算結果與現有試驗和計算數據比較，吻合程度相當好，初步檢驗和驗證了該求解器精確模擬粘性流動和計算水動力的能力。 -
When the flow of fluids in channels or pipes changes from laminar to turbulent as speed of the flow is increased, there is a large increase in drag
流體，如我們常見的水，在管道里流動時，會隨著速度的增加，由規則的層流轉為貌似毫無規律的湍流。 -
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生機理，建立了阻力系數和自噪聲的評估數值計算模型；採用物面分佈源匯法和邊界層動量積分法對繞流流場的流體動力參數進行計算，改進了轉捩區長度和邊界層位移厚度的計算，應用於航行器頭部駐點自噪聲的計算；最後設計了阻力系數和自噪聲數值計算程序模塊。 -
Topics include the principles of conservation of mass, momentum and energy ; hydrostatic behavior of floating and submerged bodies ; lift and drag forces ; dimensional anaylsis ; wave forces on ships and offshore platforms ; laminar and turbulent flows
主題涵蓋質量守恆、動量守恆及能量守恆等原理、浮體及沈體之流體靜力行為、升力、拖曳力、因次分析、船舶及離岸平臺上作用的波力、層流及紊流。 -
All of the results indicated the turbulent boundary layer had been turned into the laminar layer. the skin friction coefficient drops rapidly. this result not only proved the phenomenon of reverse transition had occurred, but also showed that this condition was drag - reducing condition
實驗結果表明板面附近的流動已由湍流流動轉變為層流流動，同時平板表面的摩擦系數較沒有溫度梯度時有大幅度下降，不僅證明了邊界層逆轉捩現象的存在，也說明了這種條件起到了減阻的效果。 -
Moreover, this paper investigates the influences of surfactant aqueous solutions on flow characteristics of a mmc. sodium dodecyl sulphate aqueous solution and alkyl polyglycoside aqueous solution are used as working fluids. the experiment results indicate that the drag reduction depends on flow velocity and temperature ; the drag reduction effects aren ’ t very obvious in laminar flow region, but when fluid enter turbulent flow region, the drag reduction increase notably, the drag reduction effects
研究結果表明，阻力減小率（ dragreduction ， dr ）與流速和溫度有關;層流區內表面活性劑的減阻效果不是特別明顯，但進入紊流區后減阻效果開始增強，尤其進入旺盛的紊流區后減阻效果大大增強;溫度提升也可增加dr ，但在溫度較高時添加sds后減阻效果的改善卻不及apg 。
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