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Consider the Navier-Stokes equations $$\frac{\partial \bf{u}}{\partial t}+\bf{u}\cdot\nabla \bf{u}=-\nabla p+\nu \nabla^2\bf{u}.$$ We can rewrite the inertial term as $$\bf{u}\cdot\nabla \bf{u}=\frac{1}{2}\bf{u}^2-\bf{u}\times\boldsymbol{\omega}.$$ Therefore, the Navier-Stokes equations can be rewritten as $$\frac{\partial \bf{u}}{\partial ...


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Why do stellar boundaries exist? Stars do not have a hard boundary or surface in the sense that your question seems to suggest you are thinking. The sun looks like a nice, discrete sphere due to optical effects. What we call the surface of the sun is the photosphere. We call this the surface, because it is what we effectively see when we look at the ...



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