Evaluation of shelter ventilation by model tests, option 1 - below ground shelters. Final report Sep 82-Dec 83

Wind-induced ventilation rates that could be achieved in a 100-man below-ground shelter with simple designs of passive flow enhancement devices (FEDs) were estimated by scale model tests in a low-speed wind tunnel. Air volume flow rates through the model were determined by using bubble flow tracers and motion photography. Test results indicate that adequate ventilation can be achieved in the type of shelter considered by the use of FEDs even at relatively low wind speeds. The study also generated guidelines for the relatively low speeds. The study also generated guidelines for the design of FEDs and their placement around stairway openings. In addition, estimates of reductions in ventilation rates due to an obstruction upstream of the windward FED and due to a decrease in the area of wall openings were made.