On the angular spectrum of nonlinearly interacting acoustic waves

Instability and evolution of nonlinearly interacting water waves.

We consider the modulational instability of nonlinearly interacting two-dimensional waves in deep water, which are described by a pair of two-dimensional coupled nonlinear Schrödinger equations. We derive a nonlinear dispersion relation. The latter is numerically analyzed to obtain the regions and the associated growth rates of the modulational instability. Furthermore, we follow the long term ...

Determination of sediments diameter using acoustic waves

The use of acoustic waves in researches related to sea water is of most importance among scientists recently. Since these waves are the only waves, transmitted in water with lowest attenuation and high speed, they can be used in many scientific fields. The main goal of this research is to better understand the physics and mechanisms of sound-seabed interaction, including acoustic penetration, p...

An angular spectrum model for propagation of Stokes waves

An angular spectrum model for predicting the transformation of Stokes waves on a mildly varying topography is developed, including refraction, diffraction, shoaling and nonlinear wave interactions. The equations governing the water-wave motion are perturbed using the method of multiple scales and Stokes expansions for the velocity potential and free-surface displacement. The first-order solutio...

survey on the rule of the due & hindering relying on the sheikh ansaris ideas

قاعده مقتضی و مانع در متون فقهی کم و بیش مستند احکام قرار گرفته و مورد مناقشه فقهاء و اصولیین می باشد و مشهور معتقند مقتضی و مانع، قاعده نیست بلکه یکی از مسائل ذیل استصحاب است لذا نگارنده بر آن شد تا پیرامون این قاعده پژوهش جامعی انجام دهد. به عقیده ما مقتضی دارای حیثیت مستقلی است و هر گاه می گوییم مقتضی احراز شد یعنی با ماهیت مستقل خودش محرز گشته و قطعا اقتضاء خود را خواهد داشت مانند نکاح که ...

Acoustic-Gravity Waves Interacting with a Rectangular Trench