Minimizing Induced Drag with Geometric and Aerodynamic Twist, CFD Validation

Aerodynamic shape optimisation, wind tunnel measurements and CFD analysis of a MAV wing

“…This reduced lift is due to the change of the incident flow direction that results from the downwash velocity induced by the free vortices, hence, a profile cross section of a wing of finite span behaves like that of a wing of infinite span (plane flow) at an angle of incidence α e . The geometric angle-of-attack α(y), measured from the zero-lift position, the effective angle α e (y), and the induced angle α i (y) are related by (19)(20)(21)(22)(23)(24)(25)(26) :…”

“…Such solutions are not only many order of magnitude faster to evaluate than modern CFD solutions, but they provide greater insight into how wing design parameters affect wing performance. The equation for the determination of the spanwise load distribution of a given wing of finite span, introduced by Prandtl (19)(20)(21)(22)(23)(24)(25)(26) , compares the reduced lift at a cross section y of a finite span wing with the lift at the same cross section of an infinitely long wing. This reduced lift is due to the change of the incident flow direction that results from the downwash velocity induced by the free vortices, hence, a profile cross section of a wing of finite span behaves like that of a wing of infinite span (plane flow) at an angle of incidence α e .…”

“…The effective angle-of-attack, α e (y), is obtained with the help of the Kutta-Joukowsky theorem, while the induced angle-of-attack, α i (y), is obtained from α i (y)= w i (y)/U, where, w i is the distribution of the induced downwash velocity along the span obtained by applying the Biot-Savart law to the semi infinitely long free vortex behind the wing and integrating over the area of the free vortices (19)(20)(21)(22)(23)(24)(25)(26) .…”

Design of an Unmanned Aerial Vehicle for Ecological Conservation

“…16 From these studies resulted the location of fairings over the landing gear, and an aerodynamic twit between wing stations 2.32 and 2.40, measured in meters, which helped to reduce the induced drag and improve wing efficiency. 13 Figures 1b) to 1d) are shown all the successive changes suffered by the design during this process (ANCE X-2, and X-3), compared with ANCE X-1, and Fig. 6 shows ANCE X-3 in a three-dimensional drawing.…”

“…This process consisted of the evaluation of the drag coefficient and the lift coefficient using theoretical, analytical, numerical and experimental tools, and then, based on literature, [11][12][13] to make changes in the aircraft shape to reduce the drag and increase efficiency.…”