Graduate Is there a stagnation point in turbulent flows not involving solids?

[rdemyan]

TL;DR

Is there a stagnation point in turbulent flows not involving solids?

Reference: https://www.physicsforums.com/forums/classical-physics.61/post-thread

When two free jets collide at some impingement angle (not necessarily a head on collision), the usual assumption is that in the impingement zone there is a stagnation point around which stream lines are deflected. From this stagnation point, a thin liquid sheet is created, which eventually breaks down into droplets at some distance downstream. Originally, all analyses assumed that there was no loss of energy in the impingement zone. However, more recent results seem to suggest that the collision is not 100% elastic. My question is: if there is in fact turbulence created in the impingement zone of colliding free jets (as a result of an energy release), can there be a stagnation point? Is a stagnation point possible in a turbulent impingement zone especially when only two liquids are involved and there is no solid object.

 

[Baluncore]

Welcome to PF.

If a steady flow is separated, by any collision, into one or more different paths, there must be a stagnation point. That stagnation point may be moving dynamically as a result of the turbulence.

Where there is counterflow, or an eddy, there must also be a fixed point.

 

[rdemyan]

I don't understand your comment regarding a fixed point. I assume you are stating that the fixed point is the stagnation point.

 

[Baluncore]

I assume you are stating that the fixed point is the stagnation point.

I am saying the inverse, that the stagnation point is a fixed point. The fluid there has zero velocity.

There may be other fixed points in a turbulent flow. If the flow divides into two paths at one of those points, then it is also a stagnation point.
https://en.wikipedia.org/wiki/Brouwer_fixed-point_theorem