Ball, J. H. | Search NASA

NASA NTRS1994

Budget analysis of FIFE 1987 sonde data

Mean thermodynamic profiles are presented for the daytime convective boundary layer evolution for three groups of sunny days in late June and early July, August, and October using data from the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) 1987 Kansas experiment. Budget models for the mixed layer evolution and the boundary layer rise are used to estimate the boundary layer top entrainment parameter. A value of A(sub R) = 0.44 +/- 0.21 is found for the mean ratio of the inversion level virtual heat flux to the surface virtual heat flux.

Betts, Alan K.↗

NASA NTRS1990

Current research in cavitating fluid films

A review of the current research of cavitation in fluid films is presented. Phenomena and experimental observations include gaseous cavitation, vapor cavitation, and gas entrainment. Cavitation in flooded, starved, and dynamically loaded journal bearings, as well as squeeze films are reviewed. Observations of cavitation damage in bearings and the possibility of cavitation between parallel plates with microasperities were discussed. The transcavity fluid transport process, meniscus motion and geometry or form of the film during rupture, and reformation were summarized. Performance effects were related to heat transfer models in the cavitated region and hysteresis influence on rotor dynamics coefficients. A number of cavitation algorithms was presented together with solution procedures using the finite difference and finite element methods. Although Newtonian fluids were assumed in most of the discussions, the effect of non-Newtonian fluids on cavitation was also discussed.

Brewe, D. E.↗