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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Motion equations of sun, moon, earth and lunar probe integrated by power series solution and analytic continuation with recursively formed derivatives
Motion equations for planar simulation of flexible Saturn 1B launch vehicles under in-flight winds using Appell equation, noting sloshing mode
Motion equations of spin stabilized rocket under thrust with jet damping, variable mass and momentum effects and all angular disturbances
Lorentz invariant method for obtaining motion equations from Einstein gravitational field equations, assuming metric tensor and field functions expansion into power series
Charged particle behavior in axisymmetric and multipolar magnetic mirrors, correlating magnetic moment variation and computing motion equations
Numerical integration of motion equations of electrons subject to electrostatic waves, considering turbulent heating
Linearized velocity profiles for turbulent free shear layers using transverse shift and longitudinal motion equation
Tornadic vortex motion equation derivation based on kinematical modification of Kelvin theorem
Partially ionized viscous plasma longitudinal wave propagation, formulating motion equations for electrons, ions and neutrals from Maxwell and Boltzmann equations
Digital computer program simulates system and related functions. Program is intended for, but not limited to, altitude control studies of rotating space station. Russel's method of formulating and solving motion equations for system of rigid bodies connected by movable joints is applied. Program features are listed.
Cable-connected spinning and orbiting satellite spring-mass system, deriving in-plane motion equations by Hamilton principle for numerical analysis
Steady state motion equations of multiple unit impact damper attached to periodically excited primary system, developing solution for mathematical model
Ball bearing dynamics, considering motion equations for four degree of freedom balls and six degree of freedom separator
NACA/NASA rotary wing aircraft research, considering rotor loads and configurations, ground resonance, blade flutter and flapping, motion equations and VTOL
Lagrangian methods yielding relativistically covariant formalism for wave packets in weakly inhomogeneous and time dependent plasma dynamics, obtaining motion equations from Euler-Lagrange equations
Periodic comets Giacobini-Ziner and Borrelly motions, determining orbits with nonNewtonian motion equations and three orthogonal nongravitational terms
In the special perturbation method, Cowell and variation-of-parameters formulations of the motion equations are implemented and numerically integrated. Variations in the orbital elements due to drag are computed using the 1970 Jacchia atmospheric density model, which includes the effects of semiannual variations, diurnal bulge, solar activity, and geomagnetic activity. In the general perturbation method, two-variable asymptotic series and automated manipulation capabilities are used to obtain analytical solutions to the variation-of-parameters equations. Solutions are obtained considering the effect of oblateness only and the combined effects of oblateness and drag. These solutions are then numerically evaluated by means of a FORTRAN program in which an updating scheme is used to maintain accurate epoch values of the elements. The atmospheric density function is approximated by a Fourier series in true anomaly, and the 1970 Jacchia model is used to periodically update the Fourier coefficients. The accuracy of both methods is demonstrated by comparing computed orbital elements to actual elements over time spans of up to 8 days for the special perturbation method and up to 356 days for the general perturbation method.
A general stability analysis of a cable-body system immersed in a fluid stream is presented. The analytical portion of this analysis treats the system as being essentially a cable problem, with the body dynamics giving the end conditions. The mathematical form of the analysis consists of partial differential wave equations, with the end and auxiliary conditions being determined from the body equations of motion. The equations uncouple to give a lateral problem and a longitudinal problem as in first order airplane dynamics. A series of tests on a tethered wind tunnel model provide a comparison of the theory with experiment.