Plenary Lecture

Engine-Structure Interactions during the Powered Flight of Atmospheric Vehicles

Professor Radu D. Rugescu
Chair of Aerospace Sciences “Elie Carafoli”
University “Politehnica” of Bucharest
Spl. Independentei 313 sector 6, 060042 Bucuresti, Romania
 

Abstract: While the base drag developed during the atmospheric flight is a well-known factor in the balance of forces that act upon the vehicle structure, its action as a thrust induced drag is less considered in flight optimization technology. The effect of that drag component over the performances of space vehicles is considerable however and stands as the main focus in the optimal flight control and thrust programming during the atmospheric ascent. The most impacting difficulty in this approach resides in the discontinuous effect of the engine-structure interaction at engine cut-off and re-start into the aerodynamic drag. The omission of this discontinuity is ubiquitous within professional flight optimization algorithms and codes. This interaction is effective up to medium altitudes of about 40 km, still they produce the entire atmospheric drag during the usual ascent to space. Consequently the analytical methods of optimization, including the variational approach, which require up to fourth order continuity of the integrand in the functional, cease to be applicable at all. A new type of variational method is presented that overcomes these discontinuities and offers a solid means of solving more general optimization problems with weak and strong discontinuities as well. Numerical results show important mass savings for Earth atmosphere ascent and especially during Titan escape ascent for return to Earth in far missions of the future.

Brief Biography of the Speaker:
Dr. Radu D. Rugescu, Romania, is affiliated with University “Politehnica” of Bucharest, Chair of Aerospace Sciences “Elie Carafoli”, Space Sciences Division since 1969, successively as Assist. Prof. and Professor. With interests and expertise in Astronautics, Propulsion Systems, Robotics, Optimization and Statistics, he teaches courses in Romanian, English and German on “Numerical methods”, “Manufacturing technology of aerospace systems”, “Astrodynamics”, “Turbomaschinen”. His research firsts include a Genuine Rocket Solid Propellant in 1959, The first Romanian liquid propellant rocket engine in 1969, the first Capture of freezing temperature of water-gas reaction in 1982, the first Romanian air-breathing rocket engine in 1987, a New variational method for discontinuous integrands in 1997, a new technology for Air captured imaging and TV live transmission from high altitude airplanes of solar eclipse in 1999, non-Keplerian gravity coupling of very large space structures in 2004.
Participates in EU funded research projects in space technology as Romanian Director. Conducts a five-year collaborative research with Texas A&M University, USA, where had performed a Fulbright research grant under sponsorship of the State Department in Space Ecology. He is known for 175 publications, including nine books. He is active member of the Astronautics Commission of the Romanian Academy since 1975, member of the International Institute for Acoustics and Vibrations since 2002 and in other societies.