Simulation of the Effect of Windbreaks on Airflow with the WAsP Engineering Program

Abstract

A number of technical complications go hand in hand with the reality of research on the effectiveness of windbreaks. Direct wind measuring in the windbreak area must be linked to specific meteorological situations that are not very frequent. A limiting factor for more frequent field measuring is also the development of surrounding areas of windbreaks. It is for these reasons that indirect methods are becoming more important. This work simulates the effect of several windbreaks in Southern Moravia (Czech Republic, Central Europe), on the modification of wind speed with the aid of the WAsP Engineering program. The windbreaks were defined in the program environment as a three-dimensional obstacles which some parameters – primarily porosity – amended as necessary during the calculation. The model results were compared with data on the wind speed from field measuring under the conditions of fresh flow perpendicular to the windbreak. The average absolute values of differences between the measured and model-calculated wind speed round about the windbreaks varied from 0.4 till 0.9 m.s−1, the greatest differences were located very close to the windbreaks (typically 50 m on leeward side). Data about the windbreak’s optical porosity based on digital photographs, obtained during performed measuring of wind speed, were also used.