{"id":396341,"date":"2024-12-04T23:35:10","date_gmt":"2024-12-04T23:35:10","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/flow-in-a-closed-loop\/"},"modified":"2024-12-04T23:35:10","modified_gmt":"2024-12-04T23:35:10","slug":"flow-in-a-closed-loop","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/flow-in-a-closed-loop\/","title":{"rendered":"flow in a closed loop"},"content":{"rendered":"<p>&lt;p&gt;Hi,&lt;\/p&gt;&lt;p&gt;I am running simulations of a circulating water tunnel. I set up peridic boundary conditions at the inlet and outlet (surfaces spaced by 1 mm) and applied a mass flow rate of 20 kg\/s so that the flow at the outlet is the same as the flow in the inlet. When I set a pressure gradient of 0 Pa\/s and run the simulation, somehow a pressure gradient appears which is completely false as seen in the picture. I am not sure if I am using the right method to simulate the flow in a circulating water channel. How would you procede?&nbsp;&lt;\/p&gt;&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/12\/04-12-2024-1733354871-mceclip2.png\" \/>&lt;\/p&gt;&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/12\/04-12-2024-1733354854-mceclip1.png\" \/>&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-396341","topic","type-topic","status-publish","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 4.9.10 - aioseo.com -->\n\t<meta name=\"description\" content=\"Hi,I am running simulations of a circulating water tunnel. I set up peridic boundary conditions at the inlet and outlet (surfaces spaced by 1 mm) and applied a mass flow rate of 20 kg\/s so that the flow at the outlet is the same as the flow in the inlet. When I set a pressure\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<link rel=\"canonical\" href=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/flow-in-a-closed-loop\/\" \/>\n\t<meta name=\"generator\" content=\"All in One SEO (AIOSEO) 4.9.10\" \/>\n\t\t<meta property=\"og:locale\" content=\"en_US\" \/>\n\t\t<meta property=\"og:site_name\" content=\"Ansys Learning Forum | Ansys Innovation Space\" \/>\n\t\t<meta property=\"og:type\" content=\"article\" \/>\n\t\t<meta property=\"og:title\" content=\"flow in a closed loop | Ansys Learning Forum\" \/>\n\t\t<meta property=\"og:description\" content=\"Hi,I am running simulations of a circulating water tunnel. I set up peridic boundary conditions at the inlet and outlet (surfaces spaced by 1 mm) and applied a mass flow rate of 20 kg\/s so that the flow at the outlet is the same as the flow in the inlet. 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