Engineering Papers⌕ Search

Engineering topics

Tsao, Y. D.

Publications and source records attributed to Tsao, Y. D..

24 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

VHF radar remote sensing of atmospheric parameters over Taiwan during the time period of Typhoon Wayne

The VHF radar located at the subtropical and low latitude observing site of Taiwan has been used to observe atmospheric parameters from the troposphere to the middle atmosphere during the time passage of Typhoon Wayne in August 1986. Time-dependent wind velocities with three-dimensional profiles have been plotted by processing the recorded data of the backscattered echo power and the Doppler spectral width of the signal returns from the VHF radar. Propagation characteristics of the gravity waves excited by the enhanced convective motions of Typhoon Wayne have been detected from the Fourier power spectrum analysis of the three-dimensional wind velocities from multiple beams of the VHF radar and their cross-correlation analysis. The density perturbations caused by the propagation of the gravity waves can be calculated from the VHF radar observations. The VHF radar can also be used to detect time-dependent vertical profiles of the liquid water content. The present study shows that the equivalent rainfall rate calculated from the VHF radar is in good agreement with the ground-based measurement of rainfall rate at the same area.

Hung, R. J.↗
NASA NTRS1988

Surface tension and bubble shapes in a partially filled rotating cylinder under low gravity

A computer algorithm is developed to simulate the profile of a free liquid surface for a cylindrical container partially filled with a Newtonian fluid of constant density, rotating about its axis of symmetry. The equilibrium shape of the free surface is governed by a balance of capillary, centrifugal, and gravity forces. The results can be used to determine the profile of a bubble at various rotating speeds under the gravity environments from low gravity, microgravity to zero-gravity. The present paper discusses the further extension of the study of the determination of bubble shape in a higher rotating speed container developed by Hung and Leslie.

Hung, R. J.↗
NASA NTRS1988

Effect of surface tension on the dynamical behavior of bubble in rotating fluids under low gravity environment

Time dependent evolutions of the profile of free surface (bubble shapes) for a cylindrical container partially filled with a Newtonian fluid of constant density, rotating about its axis of symmetry, have been studied. Numerical computations of the dynamics of bubble shapes have been carried out with the following situations: (1) linear functions of spin-up and spin-down in low and microgravity environments, (2) linear functions of increasing and decreasing gravity enviroment in high and low rotating cylidner speeds, (3) step functions of spin-up and spin-down in a low gravity environment, and (4) sinusoidal function oscillation of gravity environment in high and low rotating cylinder speeds. The initial condition of bubble profiles was adopted from the steady-state formulations in which the computer algorithms have been developed by Hung and Leslie (1988), and Hung et al. (1988).

Hung, R. J.↗
NASA NTRS1988

Time-dependent dynamical behavior of surface tension on rotating fluids under microgravity environment

Time dependent evolutions of the profile of free surface (bubble shapes) for a cylindrical container partially filled with a Newtonian fluid of constant density, rotating about its axis of symmetry, have been studied. Numerical computations of the dynamics of bubble shapes have been carried out with the following situations: (1) linear functions of spin-up and spin-down in low and microgravity environments, (2) step functions of spin-up and spin-down in a low gravity environment, and (3) sinusoidal function oscillation of gravity environment in high and low rotating cylinder speeds.

Hung, R. J.↗
NASA NTRS1987

Study of pre-storm environment by using rawinsonde and satellite observations

Rawinsonde and satellite remote sensing data were utilized to examine the prestorm environment and mechanisms for the initiation of four groups of severe storms. The storms in Altus, Oklahoma, Pampas, Texas, Bennett, Colorado, and Red River Valley, Oklahoma are described. The geographical distributions of the areas of high moisture concentration and variations of tropopause heights for the storm groups are analyzed. It is detected that in the area of a low-level high concentration of moisture, the local tropopause height is lowest at the time of the storm cloud formation and development, and the potential energy storage per unit areas for the overshootiong clouds penetrating above the tropopause is related to the intensity of the storms produced. Numerical cloud modeling was performed for the storms. The model data are compared with the satellite and rawinsonde observations, and it is noted that the data correlate well.

Hung, R. J.↗