如果取一个有旋的向量场，流体流动方向是环绕某个坐标轴的，那么就会发现它的散度是零。

And, if you take a vector field where maybe everything is rotating, a flow that's just rotating about some axis, then you'll find that its divergence is zero.

youdao

如果取的向量场是处处恒定的，所有点都是平移关系，所以没有散度，因为导数为零。

If you take a vector field that is a constant vector field where everything just translates then there is no divergence involved because the derivatives will be zero.

youdao

在散度定理中的约定是,将曲面的定向取为外法线的方向。

The convention in the divergence theorem is that we orient the surface with a normal vector pointing always outwards.

youdao

取一个向量场的散度。

OK, so you take the divergence of a vector field.

youdao

取一个向量场的散度。

OK, so you take the divergence of a vector field.

youdao