Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “spin states”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1966

Acoustic Kjeldaas edge in potassium.

Kjeldaas absorption edge in cryogenic potassium for shear magnetoacoustic wave propagation in spherical metallic Fermi surface with spin density wave ground state

SHEAR DISTURBANCE↗
NASA NTRS1965

Airplane Spinning

A summary on spinning is presented to point out the state of the art and the most important parameters', and to show the effects of these parameters on the spin and spin-recovery characteristics. The discussion presented applies to the fully developed spin, but does not apply to the spin entry, or incipient spin. The principal factors in spinning are mass distribution, which is by far the most important single parameter, and tail design, which is particularly important for conditions of zero or near-zero loading. By knowing the mass distribution and tail design, it is possible in many cases to predict whether an airplane has satisfactory spin-recovery characteristics. In other cases, however, it is necessary to make spin tests to assure satisfactory recovery.

Bowman, James S.↗
NASA NTRSDate not supplied

Discrete Rotational Energy for Polyatomic Molecules in Direct Simulation Monte Carlo

Accurate prediction of aerothermodynamic loads in thermal non-equilibrium flows requires precise modeling of internal energy exchange. While previous direct simulation Monte Carlo frameworks have successfully implemented discrete rotational energy models for diatomic species, the treatment of polyatomic molecules has traditionally relied on continuous energy assumptions that break down at low temperatures and neglect critical high-temperature corrections. This study extends the discrete rotational energy models of Boyd and Gimelshein to fully encompass polyatomic molecules. The proposed framework implements quantized rotational energy level sampling for linear, spherical, and symmetric/asymmetric top rotors. Crucially, the model incorporates centrifugal distortion to address the limitations of the rigid-rotor assumption at hypersonic temperatures, and accounts for nuclear spin parity, which dictates the permissible rotational states and macroscopic specific heats at low temperatures. The model is verified through equilibrium sampling procedures, demonstrating agreement with theoretical quantum Boltzmann distributions and accurately reproducing thermophysical properties across a wide range of temperatures.

DSMC↗