Feb 06, 2023
Fuselage boundary layer
Fuselage mockup of the glider D-B 11 in the wind tunnel; the model is installed in upside down position in the test section to gain free access for measurements on the smooth belly surface.
Especially in gliders, the friction of the flow on the surface accounts for a significant proportion of the resistance. For this reason, airfoils are used for the wings on which the flow remains laminar for as long as possible, because a laminar boundary layer generates significantly less friction than a turbulent one. Rough calculations suggest that there is also potential for savings in a laminar boundary layer on the fuselage.
As part of her diploma thesis and in cooperation between the Chair of Flight Mechanics and Flight Control and the Academic Flying Group (Akaflieg), a student from the People's Republic of China is investigating the effect of laminar length on the fuselage on the overall resistance. For this purpose, the fuselage dummy of the prototype D-B 11 of the Akaflieg currently under development will be measured in the wind tunnel.
Infrared images of a glider fuselage in the wind tunnel; the change from red to yellow coloration marks the laminar-turbulent transition.
Pitot rake for determining the total pressure profile in the fuselage boundary layer