Reynolds Number of a circular plate perpendicular to external flow

[bmv19]

Main Question or Discussion Point

Hello, I am trying to obtain how to find the Reynolds Number of a circular plate perpendicular to external flow. Thanks

 

[Andy Resnick]

The definition of the Reynolds number is here:

http://en.wikipedia.org/wiki/Reynolds_number#Definition

Use the diameter of the plate as a length scale.

 

[rcgldr]

The problem is what is the "length" of a flat perpendicular plate?

 

[bmv19]

The diameter of the cylinder is 3 inches. The length of the tube is approximately 3 feet. The set of equations that I am using say that there is an equation for a flat plate in a external perpendicular flow. I have found equations for flat plates with the external flow parallel to the plate's length as represented in the wiki-site and different school notes. However, I have yet to obtain an equation for a flat plate with a flow perpendicular to the diameter.
The problem is diagrammed below... (This flow is not a pipe. Completely filled volume)
Flow:
--> ______________ __
--> /\ ....................\ |
--> | |.................... | Diameter
--> \/_____________/ _|_
-->
.......|-----Length----|