Negative Fuselage Drag on a Tandem Wing?

mmn1239 · April 6, 2012, 21:02

Hey guys,

So, I am modeling external flow over a tandem wing aircraft in Star-ccm+. The domain size looks sufficient, the volume mesh looks good, the solution has converged and has been run for 3500 iterations, and I have double checked the force vector and force monitor orientations.

I have divided the reports into component and total values for lift and drag, and the overall total values for lift and drag look good. The other sub-components lift and drag values (front wing, rear wing, and tail) all look good except the fuse, which has a negative drag value.

When I run the fuse just by itself, it has a positive drag value and reasonable down force. So, my question is: in conjunction with the other aircraft components for a tandem configuration is it possible to have a negative drag value for the fuse component?

Thanks!

Mike

lovecraft22 · April 7, 2012, 04:52

Depending on the shape of your fuselage, it's unlikely but it may actually be possible.

April 6, 2012, 21:02	Negative Fuselage Drag on a Tandem Wing?	#1
mmn1239 New Member Mike Join Date: Apr 2011 Posts: 11 Rep Power: 4	Hey guys, So, I am modeling external flow over a tandem wing aircraft in Star-ccm+. The domain size looks sufficient, the volume mesh looks good, the solution has converged and has been run for 3500 iterations, and I have double checked the force vector and force monitor orientations. I have divided the reports into component and total values for lift and drag, and the overall total values for lift and drag look good. The other sub-components lift and drag values (front wing, rear wing, and tail) all look good except the fuse, which has a negative drag value. When I run the fuse just by itself, it has a positive drag value and reasonable down force. So, my question is: in conjunction with the other aircraft components for a tandem configuration is it possible to have a negative drag value for the fuse component? Thanks! Mike

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April 7, 2012, 04:52		#2
lovecraft22 Senior Member lore Join Date: Mar 2010 Location: Italy Posts: 339 Rep Power: 6	Depending on the shape of your fuselage, it's unlikely but it may actually be possible.