An Approximate Method of Calculating Downwash Behind a Straight Wing with Unsteady Aperiodic Motion at Subsonic Flight Speeds (Priblizhennyy Method Rascheta Skosa Potoka za Pryamym Krylom pri Neustanovivshemsya Aperiodicheskom Dvizhenii na Dozvukovykh Skorostyakh Poleta).

摘要

The calculation of downwash at the aircraft tail unit is a comparatively simple problem under stationary conditions. Unsteady downwashes created by a wing are more difficult to determine. The investigation of downwash created by a wing during harmonic vibration was presented in a quite general way in a work. The question of investigating unsteady downwashes during aperiodic motion is of equal practical interest because one must study the motion of an object with aperiodic relationships of the kinematic parameters and time when the aircraft vertically zoom-climbs (breaks away), changes from one angle of attack to another, etc. This article presents a numerical method of calculating downwash angles at the aircraft tail unit for unsteady aperiodic motion at subsonic speeds. Only straight, untwisted wings are examined, but it seems possible to devise a similar method for wings of any shape with aerodynamic or geometric twist.