Nozzle loss coefficient that increases with Reynolds number?

AI Thread Summary
The discussion centers on the behavior of drag coefficients in fluid dynamics, particularly regarding the loss coefficient in nozzles as Reynolds number increases. At high Reynolds numbers, the drag coefficient of a sphere decreases sharply due to boundary layer separation, but can increase again in post-critical separated flow. The inquiry focuses on whether a similar phenomenon can occur in internal flows, specifically in inlet flow nozzles, where an increasing loss coefficient is desired as Reynolds number rises. The conversation highlights the complexities of fluid dynamics, noting that smooth rounded inlets exhibit different characteristics compared to other designs. Understanding these dynamics is crucial for optimizing nozzle performance in incompressible flow scenarios.
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Is it possible to design an inlet nozzle (subsonic, turbulent) with a loss coefficient that increases with Reynolds number?
Hi,
I started to think about the drag coefficient of a sphere. At high Reynolds number Cd drops of suddenly when the boundary layer separates. If the Reynolds number is increased further, Cd increases with increasing Re. (I'm thinking about what is referred to as "post critical separated flow").

Does anybody know if something similar can be achieved for internal flows? Specifically in an inlet flow nozzle. I would like to have an increasing loss coefficient of the nozzle when Reynolds number increases. I'm dealing with incompressible flow (i.e. subsonic). Reynolds number around 1e5 (order of magnitude).
 
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I would think that, if something like this happened, it would occur after the throat of the nozzle, rather than before.
 
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Search term orifice coefficient vs reynolds number found many good hits. Here's a graph from one of them for square edge orifices:
Orifice.jpg

You are up against the fluid dynamics of inlet flows. Smooth rounded inlets have much different curves.
 
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