Beltrami flows have zero parallel gradients?

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SUMMARY

The discussion centers on the assertion in the wiki article regarding Beltrami flows that the nonlinear terms are identically zero. The contributor demonstrates that these terms can be shown to cancel each other, leading to a linear equation. However, they question the reasoning behind the zero value of the terms, particularly how a vorticity vector being parallel to velocity results in parallel gradients equating to zero. The contributor proposes that the equation should be expressed as ##\displaystyle (\mathbf {v} \cdot \nabla ){\boldsymbol {\omega }}-({\boldsymbol {\omega }}\cdot \nabla )\mathbf {v} =0##, suggesting a deeper physical interpretation of the condition ##J_\mathbf{v} \cdot \mathbf{v} =\mathbf{0}##.

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TheCanadian
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In the following wiki article for Beltrami flows, it is stated that the nonlinear terms are identically zero. I can easily prove the terms are equivalent and thus cancel one another, to yield the linear equation. But after a bit of algebra, I don't see why the terms are zero themselves? Why would a vorticity vector being parallel with velocity result in the parallel gradients going to 0?
 
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I think this is a mistake. It should be ##\displaystyle (\mathbf {v} \cdot \nabla ){\boldsymbol {\omega }}-({\boldsymbol {\omega }}\cdot \nabla )\mathbf {v} =0## which is all we need.

Otherwise there should be a physical meaning behind ##J_\mathbf{v} \cdot \mathbf{v} =\mathbf{0}##.
 

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