بررسی تاثیر فواصل کارگذاری خطوط لوله فراساحلی بر جدایش جریان اطراف آن ها با استفاده از مدل های آزمایشگاهی و عددی

In this paper, in order to understand the flow-pipe interaction more clearly, the variations on flow separation around offshore pipelines with different ratios of fitting distances due to the steady current have experimentally and numerically been investigated. For the experimental modeling, a number of experiments have been conducted in the Hydraulic Research Laboratory. The experiments have been carried out in a flume with 10 meters length, 0.3 meters width and 0.5 meters depth using P.V.C pipe with 6.35 centimeters in diameter (for different distances to diameter ratios of fitting). To visualize the flow separation, the polystyrene particles having 1.05gr/cm3 in density were used. Also, in order to understand the phenomenon as well as possible, the whole processes of tests have been recorded using a digital camera. For the numerical simulation section, the flow fields have been analyzed using a computational fluid dynamics software "FLUENT". Finally, the results of numerical and experimental models were compared with one to another and good agreements were achieved between them. The results showed that with increasing the fitting distance between pipes, the separation length at downstream of the second pipe was gradually decreased, however, after a given distance the two pipes behaved separately.