Asymptotically exact and nonlocal third order nonlinear evolution equations are derivedfor two counterpropagating surface capillary gravity wave packets in deep water in thepresence of wind flowing over water.From these evolution equations stability analysis ismade for a uniform standing surface capillary gravity wave trains for longitudinal perturbation. Instability condition is obtained and g...

from the mathematical point of view, the fao penman-monteith equation shows a homographic function related to the wind speed. the homographic function has horizontal and vertical asymptotes. in this issue horizontal asymptote is applicable; because the vertical asymptote occurs for negative values of wind speed but the negative sign indicates the direction of the wind speed and only the absolut...

abstract wind erosion of soils and suspended particles in iran is one of the serious environmental and agricultural problems which affect agricultural lands, water reservoirs, irrigation canals, drains and etc. therefore wind erosion control needs attention specially in arid and semi-arid regions. although in recent years, some polymeric materials have been used for improvement of structural st...

Dense urban areas restrict air movement, causing airflow in urban street canyons to be much lower than the flow above buildings. Boosting near-ground wind speed can enhance thermal comfort in warm climates by increasing skin convective heat transfer. We explored the potential of a wind catcher to direct atmospheric wind into urban street canyons. We arranged scaled-down models of buildings with...

A two-dimensional form of cross-covariance function between the radar radialand tangential-components (with respect to the direction of radar beam) of background wind errors is derived. Like the previously derived auto-covariance function for the radial-component, this cross-covariance function is homogeneous but non-isotropic in the horizontal. The autoand cross-covariance functions are used w...

We show that macroscopic heterotic strings, formulated as strings which wind around a compact direction of finite but macroscopic extent, exhibit non-trivial scattering at low energies. This occurs at order velocity squared and may thus be described as geodesic motion on a moduli space with a non-trivial metric which we construct. Our result is in agreement with a direct calculation of the stri...