Euler-Poinsot motion

惯量椭球与角动量椭球

椭球空间 橙色:Poinsot,蓝色:Binet
定点转动 无重力自由刚体

动能:\(J_1\omega_1^2+J_2\omega_2^2+J_3\omega_3^2=2T\)

角动量:\(J_1^2\omega_1^2+J_2^2\omega_2^2+J_3^2\omega_3^2=G^2\)

初始角速度:\(\boldsymbol{\omega}(t=0)=\omega_0\,\mathbf n\)

系统动能:\(T=\frac12J_n\omega_0^2\),\(J_n=J_1n_1^2+J_2n_2^2+J_3n_3^2\)

角动量:\(\mathbf G=\omega_0\,\mathbf J\cdot\mathbf n\),\(G^2=\omega_0^2K_n\)

\(2T=1,\quad J_e=\frac{K_n}{J_n}=\frac{J_1^2n_1^2+J_2^2n_2^2+J_3^2n_3^2}{J_1n_1^2+J_2n_2^2+J_3n_3^2}\),\(G^2=J_e\)

惯量椭球(Poinsot):\(\frac{\omega_1^2}{1/J_1}+\frac{\omega_2^2}{1/J_2}+\frac{\omega_3^2}{1/J_3}=1\)

角动量椭球(Binet):\(\frac{\omega_1^2}{J_e/J_1^2}+\frac{\omega_2^2}{J_e/J_2^2}+\frac{\omega_3^2}{J_e/J_3^2}=1\)

\(J_1\)= \(J_2\)= \(J_3\)= \(J_e\)= \(\boldsymbol{\omega}\)= Binet/Poinsot 半轴比= 关系=