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找动滑轮支点的几种方法
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作者 施科桦 《中学理科园地》 2016年第2期69-70,共2页
提高课堂教学的有效性,一直是受关注的问题,在教学过程中,为使学生对新知识更好地理解和接受,老师都是力求通过各种不同的方法来引导学生,而教学方法的不同,就会影响教学的有效性。动滑轮是省力杠杆,这个知识点是教学中的重点和... 提高课堂教学的有效性,一直是受关注的问题,在教学过程中,为使学生对新知识更好地理解和接受,老师都是力求通过各种不同的方法来引导学生,而教学方法的不同,就会影响教学的有效性。动滑轮是省力杠杆,这个知识点是教学中的重点和难点,其中支点的位置是学生最为困惑。本文分析多种找动滑轮支点的教学方法,寻求提高课堂教学的有效性。 展开更多
关键词 动滑轮支点 “圆盘”模型 直接给定法 实验法 台阶体验法
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Modeling and Numerical Simulation of Wings Effect on Turbulent Flow between Two Contra-Rotating Discs 被引量:1
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作者 M. Raddaoui 《Journal of Energy and Power Engineering》 2011年第1期42-47,共6页
Turbulence is a fundamentally interesting physical phenomenon which is of fundamental interest. Indeed, it is at the origin of several industrial applications, the control of energy in these industrial applications pa... Turbulence is a fundamentally interesting physical phenomenon which is of fundamental interest. Indeed, it is at the origin of several industrial applications, the control of energy in these industrial applications pass by the comprehension and the modelling of turbulent flows. Several factors are at the origin of turbulence in the complex flows, among these factors, we can quote the effect of wings in the rotating flows. The interest of this work is to model and to simulate numerically the effect of wings on the level of turbulence in the flow between two contra-rotating discs. We have fixed on these two discs eight wings uniformly distributed and we have varied the height of the wings to have eleven values from 0 to 18 mm by maintaining the same Reynolds number of rotation. The numerical tool is based on a statistical model in a point using the closing of the second order of the transport equations of the Reynolds stresses (Reynolds Stress Model: RSM). We have modelled wings effect on the flow by a source term added to the equation tangential speed. The results of the numerical simulation showed that all the average and fluctuating variables are affected the value of the kinetic energy of turbulence as those of Reynolds stresses increase with the height of the wings. 展开更多
关键词 Turbulence control of energy WING MODELING numerical simulation contra-rotating discs Reynolds Stress Model source term.
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