Evaluation of plastic nets air flow performance in a micro wind tunnel

In order to evaluate the influence of the texture characteristics of agricultural nets on the air flow passing through, a micro wind tunnel was built in the “Testing and Engineering Laboratory” at the Sachim SRL, an Italian HDPE technical textiles manufacturer. The wind tunnel allowed setting up the inclination of the net samples inside with respect to the air flow (90° perpendicular, 60°, 45°, 30°). First results in terms of coefficient of discharge of 4 flat woven round monofilament HDPE nets are reported in this paper. The net response to the air flow was based on the discharge coefficient approach based on BernoulliRSQUOs theory. Results confirmed the parabolic dependence of the pressure drop on the square of the velocity and on the porosity by means of the parameter (1-ε2)/ε2. Concerning the influence of inclination of the net on loss coefficient, a correlation with sen2θ was found, described by an exponential regression curve depending on the porosity of the net.