United Aircraft Corporation

About: United Aircraft Corporation is a company organization based out in Moscow, Russia. It is known for research contribution in the topics: Propeller & Turbine. The organization has 3137 authors who have published 3410 publications receiving 38614 citations. The organization is also known as: UAC.

Sampling and reconstruction of wave-number-limited functions in N-dimensional euclidean spaces

Abstract: The well-known Whittaker-Kotel'nikov-Shannon sampling theorem for frequency-bandlimited functions of time is extended to functions of multidimensional arguments. It is shown that a function whose spectrum is restricted to a finite region of wave-number space may be reconstructed from its samples taken over a periodic lattice having suitably small repetition vectors. The most efficient lattice (i.e., requiring minimum sampling points per unit hypervolume) is not in general rectangular, nor is a unique reconstruction function associated with a given sampling lattice. The above results also apply to homogeneous wave-number-limited stochastic processes in the sense of a vanishing mean-square error. It is also found that, given a particular sampling lattice, the optimum (mean-square) presampling filter for nonwave-number-limited processes effects an ideal wave-number cutoff appropriate to the specified sampling lattice. Particular attention is paid to isotropic processes: minimum sampling lattices are specified up to eight-dimensional spaces, and a number of typical reconstruction functions are calculated.

Propulsion Requirements for Controllable Satellites

Abstract: Propulsion requirements are determined for several controllable satellite missions. High thrust propulsion syslems such as chemical rockets and low thrust propulsion systems such as ion rockets are considered. Rendezvous missions are treated by determining minimum fuel maneuvers for small, simultaneous changes in the elements of quasi-circular orbits. Orbit transfer missions are treated by determining minimum fuel maneuvers for large changes in the elements of circular orbits. Orbit maintenance missions are treated by determining the propulsion necessary to cancel perturbations due to the atmosphere, the Earth's bulge, and the sun and moon. A closed-form analytic solution is found for the optimum low thrust transfer between inclined circular orbits of different radii. (auth)

Intra-Stator Transport of Rotor Wakes and Its Effect on Compressor Performance

Abstract: Rotor wakes intrastator transport effects on high Mach number axial flow compressors performance, considering stagnation temperature profile and rotor blade loss factor