{"id":366094,"date":"2024-05-08T13:19:54","date_gmt":"2024-05-08T13:19:54","guid":{"rendered":"\/forum\/forums\/topic\/air-water-interface-simulation-in-fluent\/"},"modified":"2024-05-08T13:19:54","modified_gmt":"2024-05-08T13:19:54","slug":"air-water-interface-simulation-in-fluent","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/air-water-interface-simulation-in-fluent\/","title":{"rendered":"Air-water interface simulation in fluent"},"content":{"rendered":"

Hello,<\/p>\n

I am new to ANSYS and am trying to simulate air flow over still water(not as a tank but a free surface such as a lake\/pond). I am using a rectangular 2D mesh as below using the multiphase VOF<\/strong> model with the SST k-w solver <\/strong>. I have enabled gravity and implicit body forces and am using an explicit solver. I am using a velocity inlet with a log profile and a pressure outlet as boundary conditions. I used constant surface tension of 0.072 for the interface and did not enable surface tension force modelling.<\/p>\n

For the velocity inlet, I have given volume fraction 0 for the secondary phase(water).<\/p>\n

For the pressure outlet, I have given backflow fraction as 1 for water.  <\/p>\n

All the other boundaries, I have assumed wall conditions and have tried the no-slip conditions and specified shear(0 shear since water and air have relatively negligible shear)<\/p>\n

. \"\"<\/p>\n

I have used these reference values computed from inlet<\/p>\n

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<\/p>\n

<\/p>\n

I have tried 2 separate approached with this setup (for steady-state simulation<\/strong>), both did not work out and I would appreciate suggestions on how to proceed or what is happening in the model.<\/p>\n

Approach 1: Patching just a water region<\/p>\n

I patched the bottom part of the rectangle(below the inlet) after hybrid initlialisation<\/strong> as having a volume fraction of 1 for water. I get phase seperation but after running the calculation I get a lot of phase mixing<\/p>\n

<\/p>\n

I suspected this was due to an already initialised velocity field in the domain before I did patching for the water region<\/p>\n

\"\"<\/p>\n

Approach 2: Patching phase and velocities<\/p>\n

I tried patching the x and y velocities for both phases as well(i defined both phases as different regions and applied my default velocity conditions to them(only x-direction velocity for air))<\/p>\n

I tried running this calculation for 1000s and the simulation crashed because of high residuals and non-convergence.<\/p>\n

 <\/p>\n

I do not understand why water is behaving in this manner and my calculations are going haywire.<\/p>\n

Does a patch not define cell properties like density and viscosity? If so, how do I proceed with this, should I define seperate geometries for the phases or is there some settings i can modify?<\/p>\n","protected":false},"template":"","class_list":["post-366094","topic","type-topic","status-closed","hentry","topic-tag-air-waterflow-1","topic-tag-ansys-fluent","topic-tag-fluid-wind-1","topic-tag-interface-boundary"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t