HI,

I am relatively new to Fluent and bit confused over the reference values setting. As I followed the examples, sometimes they are considering projected area( ex:cylinder) normal to the flow and in some cases length of the object(ex: aerofoil). Could some one explain me the proper area to be selected?

Thanks, Shivakanth.

it really simple,

for example if you have to calculate the drag coefficient for a geometry, like flow passing a cylinder, in this case you have to specify its bases area for its reference area, if you remember the formula of drag coefficient, there is an area term present and this area term is taken as reference area in fluent.

same with length, when u have to calculate moment coefficient you have to specify it !!

hope u understand !!

Hi Syed... Thanks. Just for confirmation, if a take a plate bent in the form of an arc, the arc length would be reference area(unit depth) and reference length right?

Thanks, Shivakanth.

dear, when ever u generate a report, always mention your reference condition becasue for certain gemotries like a sphere, it is understood to take its projected area as reference area, so therefore i advise u only to take standard refernce for an analysis,else where ever mention.

the question of reference parameters are stickly concerned with the geometry and type of problem, therefore do mention your reference condition in your report so other could understand it.

for fun, just take a problem concerning flow over a cylinder form any fluid mechanics book, solve it both analyticaly and computationally then u will have an idea of reference parameter

Hey Syed...

Thanx.. as u said, let me do some homework and get back to you.

[hassan79]

hi sir

could u plz told me about refence value i wana calclate surface nuselt no in expansion pipe( diffrent diameter ) with down strean what should i used for :
temprature
lenghth
area
height
velocity
;;;;;;;




thank u

[kamran651]

Bro, it entirely depends on your problem..what you have taken temperature, length, and depth..