Roll waves are known to occur in the frictional flow of a thin layer of water down an inclined solid surface. For a layer of constant depth, the formation of these waves on a solid plane with small slope angle have been explained as a hydrodynamic instability occurring above a critical Froude number by analyzing the temporal stability of the constant velocity flow. Here we analyze the linear, s...

A water surface slope limiting scheme is tested and compared with the water depth slope limiter for the solution of one dimensional shallow water equations with bottom slope source term. Numerical schemes based on the total variation diminishing RungeKutta discontinuous Galerkin finite element method with slope limiter schemes based on water surface slope and water depth are used to solve one-d...

Current models for the microwave polarimetric brightness temperature of the sea surface are reviewed. Results from the physical optics (PO), composite surface, and small slope approximation (SSA) theories are illustrated and compared with an empirical model. All models are shown to predict both first and second harmonic azimuthal variations of sea brightnesses, but the physical effects captured...

we have calculated the phonon frequencies of kc1 along symmetry directions using an approach which is a combination of the frozen phonon and force constants methods. we also calculated griineisen parameters for all modes at x and l points in the brillouin zone. finally, the slope of acoustic dispersion curves around zone center were used to calculate the three independent elastic coefficients c...

The first positive detection of the X-ray background fluctuations at small angular scales is reported. ROSAT PSPC archive pointed observations are used to measure fluctuations at scales of 0. 03−0. 4. The pointings have been selected from an area free from galactic contamination. At separations below ∼ 0. 1 clusters of galaxies become a substantial source of the background fluctuations. The aut...