A question about flow in a duct; in this case, a duct under the fuselage, just aft of the firewall, exhausting engine cooling air.
The crossection of the duct fairs into the belly of the fuselage as shown in Design A. Design B has slightly less area, due to squaring the inside corner where the duct attaches to the fuselage. The external surface is not drawn in Design B, but it, too would be faired into the fuselage belly.
Does the acute angle between the duct and the fuselage in Design A cause more drag than the 90 degree angle in Design B?
If so, is the drag difference enough to allow Design B to flow more air than Desigh A, given the same pressure drop in the duct?
Thanks,
BJC
The crossection of the duct fairs into the belly of the fuselage as shown in Design A. Design B has slightly less area, due to squaring the inside corner where the duct attaches to the fuselage. The external surface is not drawn in Design B, but it, too would be faired into the fuselage belly.
Does the acute angle between the duct and the fuselage in Design A cause more drag than the 90 degree angle in Design B?
If so, is the drag difference enough to allow Design B to flow more air than Desigh A, given the same pressure drop in the duct?
Thanks,
BJC