Talk:Landau–Squire jet

Problem description, readability

The text and derivation seems to have been written with pure mathematics in mind. For readers more used to seeing the navier-Stokes equations applied to "real" flows, it is hard to follow, and needs some more explanations. What is a "point source of momentum"? After several re-reads, I believe the idea is that no fluid is injected at the origin, but that the fluid at the coordinate origin is instantly accelerated to a certain velocity (without affecting pressure, density, temperature, I suppose? Or is the energy equation still kept balanced? In that case, T, rho and P would drop), which causes a jet to form. Which way is it pointing, and what is its extent? Somewhere near the end of the derivation, a sentence mentions "conical jet", as if that was obvious. But if it starts at a point, then why is there a "jet boundary", wouldn't the velocity profile be a completely smooth "bump" similar to a Gaussian distribution? What state does the jet expand to? It's also nice to have figures of the flow field, but they appear to be mislabelled. The figure caption says "streamlines", but the figures show contour maps of some unnamed quantity, no streamlines. My first assumption was that this would be velocity, but in that case there would be no jet. Neither pressure nor Mach number, density or temperature seem to make sense, nor does viscous stress (I think...). A more straightforward explanation is thus in order. — Preceding unsigned comment added by 2001:983:6D3F:1:F537:78A2:7CC4:972F (talk) 22:57, 30 December 2020 (UTC)