elliptical velocity 中文意思是什麼
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Based on the review, the fluid flow and heat transfer in the curved circular and rectangular pipes have been researched by employing perturbation method and numerical simulation with a physical model under the rotational orthogonal curvilinear coordinate in a rotating curvilinear pipe with multi - parameters. we firstly analyzed the fully developed fluid flow and heat transfer, mixed convection heat transfer, the development of flow and heat transfer in the inlet in different cross section ( circular, elliptical, annular and rectangular crossection ). the variations of the secondary flow, axial velocity, distribution of temperature, the friction force on the wall, the ratio of friction factor as well as the nusselt number with different dimensionless parameters had been examined in detailed
本文在總結和分析了一個世紀以來有關曲線管道流動和換熱特性的研究成果的基礎上，以旋轉正交曲線坐標系統下的多參數旋轉螺旋管道中的對流傳熱為物理模型，通過攝動方法和有限體積法，首次對各種截面（圓截面、橢圓截面、環形截面、矩形截面）旋轉曲線管道內充分發展流動的流動結構和傳熱特性（包括耦合對流傳熱特性）以及旋轉曲線管道開口段發展流動的流動結構和換熱特性進行了系統的數值模擬和理論分析，詳細討論了各種無量綱參數對管道內軸向速度分佈、二次流結構、溫度分佈、壁面摩擦力、摩擦系數比以及管道nusselt數的影響，獲得了若干創新性成果。 -
In order to realize smooth movement of mechanical system at a low velocity, the following work investigates new types of linear ultrasonic motors and antifriction technique by superposing the motor ’ s elliptical vibrating motion at the friction interface to change frictional characteristics, produce ultrasonic lubricant effect and realize active control of friction force
本文研究新型超聲波馬達，利用其產生於摩擦界面的橢圓軌跡超聲振動引起的潤滑效應和摩擦接觸行為的改變來減小摩擦力的大小，完成對摩擦力的主動控制，實現機械繫統的低速平滑運動。
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