Scope of form5 Fuselage Drag Calculations

Tom FTom Falls asked 9 months ago

Does the fuselage drag analysis include drag calculations for any of the friction drag + the form factor drag + interference drag? Does the total moment calculation for the plane include the moment caused by the fuselage drag? For example, in the case where the fuselage is translated down (-ve Z dimension) from the wing as in a “high wing” airplane? Also when the AoA is different than in level flight the projected area of the fuselage at right angles to the air stream will increase and I assume would increase the form factor drag thus increasing the total fuselage drag?
Thanks,
Tom

1 Answers
André Deperroistechwinder Staff answered 9 months ago

The Karman-Schoenherr and Prandtl-Schlichting models are empirical models which only account for skin-friction drag. The impact of this drag on the pitching moment is taken into account in flow5.
Both models only use the fuselage Reynolds number and the wetted area, and are independent of angle of attack:
https://www.cfd-online.com/Wiki/Skin_friction_coefficient
Somebody has pointed out that these models, as implemented in flow5, seem to overpredict friction drag, so this is something I’ll investigate shortly, and improve if there is a possibillity.
André