بهینه کردن طول نازل تونل باد عمودی با استفاده از روش‌های عددی و تجربی

Nozzle is an important component in vertical wind tunnels.nozzle length of this type of wind tunnel is very important, so with length reduction, the cost of building of wind tunnel can be reduced. using fluent software, the flow in the nozzle is simulated and its length is optimized. in this paper, considerations such as reduction of the ratio of nozzle cross section area at inlet and outlet and nozzle length to inlet diameter ratio and truncation of the nozzle cone at the outlet have been used to reduce nozzle length. numerical results indicate that the nozzle with the ratio of cross section 6.25 and nozzle length to inlet diameter ratio 0.9 for designing is suitable. in experimental method, the model of nozzle have built and air flow through the nozzle was studied using hot-wire anemometer. according to the results, the nozzle length can be reduced up to 60%.he abstract should be written with 100 to 200 words (times new roman 9).