We provide an example of a smooth, divergence-free $\nabla \cdot \vec{u}(\vec{x})=0\vec{u}(\vec{x})$ for incompressible fluid occupying all of space, and smooth vector field $\vec{f}(\vec{x}, t)$ for which the Navier-Stokes equation for incompressible fluid does not have a solution for any position in space at . The velocity vector field $u_{i} (\vec{x})=2\frac{x_{h(i-1)} -x_{h(i+1)} }{\left(1+\sum {j=1}^{3}x{j}^{2} \right)^{2} }i={ 1,2,3} h(l)=\left{\begin{array}{ccc} {l} & {;1\le l\le 3} & {} \ {1} & {;l=4} & {} \ {3} & {;l=0} & {} \end{array}\right.$ is smooth, divergence-free, continuously differentiable , has bounded energy , zero velocity at coordinate origin, and velocity converges to zero for $\left|\vec{x}\right|\to \infty\vec{f}(\vec{x},t)=(0,0,\frac{1}{1+t^{2} (\sum {j=1}^{3}x{j} )^{2} )} f(\vec{x},t)\in C^{\infty }\left|\vec{x}\right|\to \infty\vec{u}(\vec{x})\vec{f}(\vec{x}, t)$ in the Navier-Stokes equation for incompressible fluid results with three mutually different solutions for pressure , one of which includes zero division with zero term at , which is indeterminate for all positions .

生成讲解博客的中文版本

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