{"id":43314,"date":"2020-04-27T17:41:48","date_gmt":"2020-04-27T17:41:48","guid":{"rendered":"\/forum\/forums\/topic\/residual-errors-are-0-zero-for-the-first-few-iterations-fluent\/"},"modified":"2020-04-27T17:41:48","modified_gmt":"2020-04-27T17:41:48","slug":"residual-errors-are-0-zero-for-the-first-few-iterations-fluent","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/residual-errors-are-0-zero-for-the-first-few-iterations-fluent\/","title":{"rendered":"Residual errors are 0 (zero) for the first few iterations (Fluent)"},"content":{"rendered":"

I am new to ANSYS, and I wanted to use ANSYS FLUENT to simulate water flowing past a sphere. To decrease time of simulation, I am using 2D axisymmetric mesh. The mesh, together with the boundary conditions I used for this problem, are shown below.<\/p>\n

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When I run my simulation, the residual errors for continuity and velocity are 0 (zero) in the first 5 iterations. Only after that I get non-zero residuals (3.26e-17 for continuity, 1.43e-4 for x velocity and 7.39e-5 for yvelocity in iteration 6). The residuals decrease afterwards, and the results seem correct if I let the simulation running for a sufficiently large no. of iterations.<\/p>\n

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Does anyone know what is causing the issue in the first 5 iterations? It is a bit of an inconvenience to me because I cannot set a convergence criterion under Residual monitors<\/em> (if I do so, the simulation ends after 1 iteration saying the program has converged).<\/p>\n

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A bit of additional information that may or may not be useful:<\/p>\n

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