James W. Rottman

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The results of an experimental study of the non-Boussinesq lock-exchange problem are described. The experiments were performed in a rectangular channel using water and either a sodium iodide solution or a sodium chloride solution as the two fluids. These combinations of fluids have density ratios (light over heavy density) in the range 0.61 to 1. A(More)
The authors investigate the extent to which the contrast brightness of ship tracks, that is, the relative change in observed solar reflectance, in visible and near-infrared imagery can be explained by the microphysics of the background cloud in which they form. The sensitivity of visible and near-infrared wavelengths for detecting reflectance changes in(More)
The solitary waves that have been observed in the atmosphere fall broadly into two classes: those that propagate in a fairly shallow stratified layer near the ground and those that occupy the entire troposphere. We present a survey of the observations of both types of solitary waves. The generation mechanisms differ substantially for these two types of(More)
A previously derived approximation to the standard Fourier integral technique for linear mountain waves is extended to include nonhydrostatic effects in a background flow with height-dependent wind and stratification. The approximation involves using ray theory to simplify the vertical eigenfunctions. The generalization to nonhydrostatic waves requires(More)
Dave Broutman,1 James W. Rottman,2 and Stephen D. Eckermann3 1Computational Physics, Inc., Springfield, Virginia 22151; email: daveb@uap2.nrl.navy.mil 2Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093; email: jrottman@ucsd.edu 3E.O. Hulburt Center for Space Research, Naval Research(More)
A Fourier method is used to model mountain waves that have nearby turning points in a wind jet. In Fourier space, the propagation equations are solved by ray theory. To correct for the ray singularity at a turning point without time-consuming special-function evaluations, the ray solution is linearly interpolated across the breakdown region. The Fourier(More)
The ray solution for stationary hydrostatic mountain waves has a singularity along the vertical axis directly over the mountain. We use Maslov’s method to improve the ray prediction. The ray solution is determined in the wave-number domain and is then mapped by inverse Fourier transform to give a spatial description of the wave Ž eld that approximates the(More)
The evolution of a counter-rotating vortex pair in a stably stratified fluid is investigated using direct numerical simulations. The study focuses on the short-wavelength elliptic instability occurring in this flow and the subsequent decay of the vortices. Depending on the level of stratification, as characterized by the Froude number which indicates the(More)
This paper describes the Liquid Spill Modeling System (LSMS), a computer model designed to predict the spreading and vaporization of spills of multicomponent cryogenic and volatile liquids. Using an efficient finitevolume formulation, LSMS solves numerically the governing partial differential equations in the shallow-water approximation to give the pool(More)