Several clean agricultural screens were tested to determine force and
static pressure drop across the screen created by airflow through the
screen. Wind pressures on screens and static pressure drop across scre
ens increased exponentially with increases in apparent air velocity. F
abric density, configuration, and dimensional characteristics greatly
affected wind pressures and static pressure drops, Forces against the
screens were not merely a function of the net solid area of screening
material. The coefficient of drag was calculated at various apparent a
ir velocities for each screen; it was unstable at lower apparent air v
elocities but tended to stabilize to one value for the higher velociti
es through each screen.