Wind tunnels are a key experimental tool for the analysis of airflow parameters in many fields of application. Despite their great potential impact on agricultural research, few contributions have dealt with the development of automatic control systems for wind tunnels in the field of greenhouse technology. The objective of this paper is to present an automatic control system that provides prec...

Introduction High tunnel production is increasing in Iowa as they provide protection from wind and frost and help extend the growing season. Although production aspects inside high tunnels are similar to field production, high tunnel environment is challenging especially when it comes to temperature management. During summer, temperatures rise fairly quickly in high tunnels and can detrimentall...

*Lawrence J. Hagen, USDA-ARS, Wind Erosion Research Unit, Throckmorton Hall 2004, Kansas State University, Manhattan, KS 66506. *Corresponding author: [email protected]. Contribution from USDA-ARS in cooperation with Kansas Agric. Exp. Sta., Contribution No. 99-389-A. ABSTRACT Assessment of wind erosion parameters applicable to the field scale using wind tunnels requires attention to both scal...

The reliable measurement of pressures on low-rise buildings in the atmospheric boundary layer (ABL) flow remains a challenge, as has been shown by the large discrepancies among results obtained in different wind tunnel facilities or even in the samewind tunnel. Twomajor causes of the discrepancies are the difficulty of simulating large-scale, low-frequency turbulent fluctuations uniformly acros...

Hydroelectric power plants’ open-type surge tanks may be built in mountains subject to the provision of atmospheric air. Hence, a ventilation tunnel is indispensable. The air flow in the ventilation tunnel is associated with the fluctuation of water-level in the surge tank. There is a great relationship between the wind speed and the safe use and project investment of ventilation tunnels. To ob...

Wind erosion threatens soil productivity and air quality in the Columbia Plateau region of the Pacific Northwest United States. Management practices are sought that will abate erosion, but limitations exist in measuring the effectiveness of these practices in reducing erosion. Portable wind tunnels are ideal tools that can be used to assess the impact of management practices on erosion. A porta...

Aeolian processes occur throughout the Solar System and likely on extrasolar planets as well. Models based on data collected in boundary layer wind tunnels have contributed to understanding the physics of these processes. Planetary wind tunnels allow simulation of conditions (atmospheric pressure, density, or kinematic viscosity) on extraterrestrial bodies, and their use over several decades ha...

the direction and speed of winds play an important role in the occurrence of pollutions and dust stormas well as location placement for the establishment of industries and the expansion of cities. yazd is a dry area of iran, and constantly exposed to the dust particles in the air; and this in terms of human life and health issues are of special importance. in this paper a day when due to the am...

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...