Snow drifting is a typical natural disaster, and an increasing importance has been attached to its theory research and field observation for the sake of cold region engineering. Numerical simulation, as an efficient method of studying snow drifting, promises to be widely applied in this field. In this paper, the finite element method is used to simulate the wind velocity field. Selected upwind,...

We propose a simple experiment to study delocalization and extinction in inhomogeneous biological systems. The nonlinear steady state for, say, a bacteria colony living on and near a patch of nutrient or favorable illumination ("oasis") in the presence of a drift term ("wind") is computed. The bacteria, described by a simple generalization of the Fisher equation, diffuse, divide A --> A + A, di...

In this using paper a method is presented for the aerodynamic and structural analysis of a horizontal axis wind turbine using simplified methods. In the first part of the program the optimum rotor configuration for twist and chord is determined using the momentum and blade element theories for a rotor without coning or tilting and assuming zero drag average wind velocity. Then coning angle and ...

We analyzed intermittency in the solar wind, as observed on the ecliptic plane, looking at magnetic field and velocity fluctuations between 0.3 and 1 AU, for both fast and slow wind and for compressive and directional fluctuations. Our analysis focused on the property that probability distribution functions of a fluctuating field affected by intermittency become more and more peaked at smaller ...

*Katharina Helming, Center for Agricultural Landscape and Land Use Research (ZALF), Eberswalder Str. 84, D-15374 Muencheberg, Germany. *Corresponding author: [email protected] ABSTRACT The kinetic energy of rainstorms plays a paramount role in surface sealing, runoff, and erosion processes. Typically, the kinetic energy rate is calculated based on terminal velocity of vertically falling raindrop...

In order to recognize the wind erosion situation of a region, the survey of its windiness is not sufficient and the physical characteristics of earth are of importance too. In fact, the outbreak of dust storms in a region is due to the sensitivity of earth and domination of wind in that region. In this investigation we have tried to find a way for determining the regions in which a dust storm i...

erosion by wind is one of the most important factors in desert environment. prevailing winds can shift sand dunes and affect their accumulation. also, wind regime determines the direction of sand dune mobility. the aim of this research was to investigate sand drift potential using sand movement models. for this research, wind data between 1986 and 2005 from the meteorological station of yazd we...

background: recently, we introduced solar related geomagnetic disturbances (gmd) as a potential environmental risk factor for multiple sclerosis (ms). the aim of this study was to test probable correlation between solar activities and gmd with long-term variations of ms incidence. methods: after a systematic review, we studied the association betwee n alterations in the solar wind velocity (vsw...

Research on wind turbine technologies have focused primarily on power cost reduction. Generally, this aim has been achieved by increasing power output while maintaining the structural load at a reasonable level. However, disturbances, such as wind speed, affect the performance of wind turbines, and as a result, the use of various types of controller becomes crucial.This paper deals with two ada...