第4章流体动力学基本定理_4,5_2004技巧.ppt

Bernoulli方程：速度分布 压力分布 动量方程： 动量变化 合力。 ;（系统）;求解步骤： （1）取坐标系； （2）假定力:如设F为外界给流体的力，则物体受力F’ = －F； （3）取控制体：速度和压力为已知的面；物面或流面。物面或流面上 而物面往往就是要求的受力面。;4.4.2 动量矩方程;Example 4-5 大气中二元流冲击平板 Given：b0、V0，a，p0，不计粘性。 Find：流体对平板的作用力。;得 ;4.5 旋涡运动基本定理 ;Kelvin定理的几个推论：;4.5.3 Helmholtz 定理 - 涡线和涡管保持定理;④;④; Sir William Thompson (Lord Kelvin), born in Belfast, Contributed significantly to the field of hydrodynamics as is evidenced by his 661 papers and 56 patents. When 11 years old, he entered the the University of Glasgow, leaving in 1841 to enter Perterhouse, Cambridge University, to further his education. To meet Biot in Paris. In 1846 he became Professor of Natural Philosophy at Glasgow, a post he held for 53 years. Contributions: Long waves, heat conduction, thermodynamics, submarine cables. Philosophy: “There cannot be a greater mistake than that of looking superciliously upon practical applications of science”. Buried: in Westminster Abbey. ;英国及欧盟国家;4.5.4 Biot—Savart定理 — 涡线的诱导速度;Biot-Savart 定理： ;⑦