My confusion has arisen from the observations I have made regarding fluid flow through narrow passageways in fluid filled enclosed channels.
Here the Reynolds number is high, suggesting turbulent flow but the fluid appears not to mix and appears to flow without turbulence.
I described this to a college who simply said the flow regime was streamline.
"For engineering purposes, flow in pipes is usually considered to be laminar if the Reynolds number is less than 2000, and turbulent if the Reynolds number gate valve is greater than 4000. Between these two values lies the "critical zone" where the flow ... being laminar, turbulent, or in the process of change (ie, transitional), depending upon many possible varying conditions is unpredictable. Careful experimentation has shown that the laminar zone may be made to terminate at Reynolds numbers as low as 1200 or extended as high 40,000, but these conditions are not expected to be realized in ordinary service."
If you're seeing a laminar flow at high Reynolds numbers, in all likelyhood you've got a special condition, outside of ordinary service.
As it normally goes in science, the exception proves the rule, or for every rule there is an exception.

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