# Intial water-air conditions Mixing tank

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 March 1, 2016, 10:35 Intial water-air conditions Mixing tank #1 New Member   Sonny Calderon Join Date: Mar 2016 Posts: 1 Rep Power: 0 Hello, I'm trying to do a simulation of a mixing tank that is partially filled stirred by and impeller. I have set the physics model to be a multiphase eulerian model and have already set both phases (Water on bottom and AIR on top) and put the intersection as an continuous-dispersed intersection, water being continuous and air dispersed. I don't know if this is correct since the air is on top of the water. My main problem is that I do not know how to specify the level of water in the tank. It most be a simply thing to do but I'm new to the software and all I've done has been with the user guide. If you have any comments that are not related to the water level that might help with the simulation I'd be very grateful. Thank you!

 March 31, 2016, 04:59 #2 Member   Join Date: Aug 2014 Location: Germany Posts: 77 Rep Power: 11 You can have a look at the cavitation tutorial. They specify water to left side of domain and air to right using Field Functions. Guess you can do something simliar, I'm also new to starccm, so I'm not sure if this is the standard easiest method. Tutorials > Multiphase Flows > VOF Cavitation > Setting initial conditions

 March 31, 2016, 07:54 #3 New Member   Robert Gottschalk Join Date: Mar 2016 Posts: 5 Rep Power: 10 as harry123 said you have to create two field functions. One is for water and one for air. Thats what I use: (\$\$Centroid(@CoordinateSystem("Laboratory.Cylindri cal 1"))[2]<=0.001)? 1:0 first you have to refer to a coordinate system if you not wanna use the original one. The [2] represant the z coordinate. After the bracket comes the value you one use. The first on is used when your formulation in the brackets is true. Otherwise the second value will be used. You need the same field function for air again. Just chance the 1 with the 0. At last you have to select this function in the physics node. harry123 likes this. Last edited by Rob87; April 1, 2016 at 01:46.

 Tags eulerian multiphase, intersection, mixing tank, multiphase flow