FLOW THROUGH INCLINED SCREENS: COMPARISON BETWEEN EXPERIMENTAL AND CFD RESULTS
To explore ways by which the resistance of screens to airflow can be reduced, wind tunnel experiments were compared with Computational Fluid Dynamics (CFD) simulations. A screen with porosity 0.4 was installed at the inlet of a sub-tunnel that was placed on the floor of the wind tunnel; the upper half of the wind tunnel was open to the free air stream. The effect of screen inclination relative to mean flow direction on velocity profiles downstream the screen was studied. Three screen inclinations were tested: 45, 90 (normal to flow direction) and 135°, where zero degree angle points towards the upstream direction. The case of 90° was studied by installing a vertical screen at the center of the sub-tunnel. The velocity profiles were measured using an omnidirectional hot wire anemometer. Three dimensional CFD simulations were conducted to explore the same configurations using the ANSYS-CFX software package. The experimental and CFD results are in good agreement with respect to the air velocity distribution downstream. Both CFD and experimental results show that the mass flow rates within the sub-tunnel were higher by almost 30% through screens that are inclined 45° to the mean flow than through screens that are inclined 135°.
Teitel, M., Dvorkin, D., Haim, Y., Tanny, J. and Seginer, I. (2008). FLOW THROUGH INCLINED SCREENS: COMPARISON BETWEEN EXPERIMENTAL AND CFD RESULTS. Acta Hortic. 797, 139-144
screens, velocity, resistance, greenhouse ventilation, screenhouse