FEDSM2008-55074 NUMERICAL EFFECT OF AIRFLOW FROM A LOWER CANOPY (BLUFF BODY) INTO AN UPPER CANOPY IN STEADY AND TURBULENT CONDITION

ABSTRACT: In this paper, a 3-D flow field around two bluff bodies in an incompressible fluid is modeled The vertical distances between the bluff bodies, the cross sectional area, and also the vent ratio of bluff bodies are varied here. Vertical distances of these two bodies are varied form zero to half, equal, double and triple the radius of the body with a vent on it (lower body). Flow condition is considered 3D, steady, turbulent, and incompressible. The drag force on each body and also the pressure around the two bodies are calculated. From the numerical results, it can be seen that, the drag force is constant over the range of zero to twenty percent of the vent ratios and for higher vent ratios when the upper bluff body is smaller than the lower one the drag force decreased, and it increased when the upper bluff body is larger than the lower one