The Legacy of Camillo Possio to Unsteady Aerodynamics

Abstract

First a brief overview is given of Camillo Possio's short but outstanding and fruitful career. This is followed by an outline of the state of the art in flutter and unsteady aerodynamic research, and the challenges and problems like high-speed flight that arose in aircraft development at that time. Possio's first publications on gas dynamic and supersonic problems are reviewed. The main focus is on the 1938 report on unsteady subsonic compressible 2D flow that became famous and was named after him, because he was the first person to developed an unsteady compressible aerodynamic theory, which was urgently needed in those years. The theory, which is based on Prandtl's acceleration potential is briefly outlined. Some discussions and comments that took place in Germany and other countries at that time highlight the importance of this work for the scientific community. Early solutions of Possio's integral equation developed by himself and later ones developed by other researchers are presented, as well as approaches that extended the theory to 3 dimensional flows before the war, like Kuessner's theory, which was probably influenced by Possio. Finally Carnillo Possio's later scientific contributions to wind tunnel interference and to hydrodynamics are described. A summary of some developments of the 2nd half of the 20th century demonstrate that Camillo Possio created a milestone for modern aircraft research during his very short career.

Asymptotical form of Possio integral equation in theoretical aeroelasticity

“…However, it became clear that theoretical investigation of the destroying structural vibrations, knowledge of both the elastic oscillatory behavior of the lifting surfaces and the oscillatory motion induced by unsteady air-loads, were urgent scientific challenges. In mid-1920s of the last century a systematic study of wing flutter and unsteady aerodynamics has been initiated at such centers as Göttinger in Germany and Turin in Italy [16].…”

“…For example, the first dynamic response problem was registered with Junkers F13 in 1930. Flow separation during a pull-up maneuver as a reaction on gust producing wing buffet either on wings or on the tail-planes were among the causes [16]. The destruction of a big JU90 aircraft in 1938 was probably caused by bending-torsion flutter of the bi-tailplane [16].…”

“…After this very brief exposition addressing the origin of the Possio integral equation (for more details, see [3,5,16]), we recall the main setting of the problem in the present paper. As has been mentioned at the beginning of the Introduction, we are going to focus on the problem of solvability of the Possio equation.…”