[undziabundzia]

Hey, it's first time, when i have troubles with saving mesh into msh. file.

This is what I get from ICEM: (attach)

Please

[shereez234]

Are you trying to solve in Fluent? Then choose output solver as fluent.

[undziabundzia]

Yea, I already found it out . Now I have another problem, with unstability flow around ship. I have time to 15.01 on my collage. Meybe do You know, how to fix it ?
Here is my fluent setup: powietrze = air; wodamorska = seawater
http://postimg.org/gallery/36ok2z8py/07d3d352/

I really, really need to help, divergence is eating my mind , and if i won't do this, i will lose my life..


Greetings Jacob

[shereez234]

Your mesh probably needs a lot of work based on what I see. Improve the mesh until fluent gives you orthogonal quality > 0.01

[undziabundzia]

Thank You very much for Your reply !

I have orthogonal quality = 0.34 with tetra/tri unstructed mesh, I have also 14 prism/quad layers, becouse i would to make solution with visocity aspect.

Could You give me some more advice ?

Greetings and Thank You - Jacob

[shereez234]

Orthogonal quality 0.34 in ICEM/ANSYS meshing? or Fluent?

Can you post a picture of mesh quality in fluent? from the picture you uploaded it seems that you do not have a proper boundary layer.

We can discuss further issues then. I just want to make sure mesh quality is reasonable to start helping you with other issues,

[undziabundzia]

Dear Friend Shereez234

Thank You, I am really happy, of your responding. Here I attach printsreen, where is evidence of mesh quality.


Waiting for Your new reply. Your friend Jacob.

ps. not to much official ?

[shereez234]

Your mesh is more than fine then.

Okay So let me get this right. You are doing a 3 Dimensional Unsteady- Time dependent Volume of Fraction - External flow analysis around the ship. Why don't you try PISO instead of simple with Small time step size?

[undziabundzia]

Unsteady - it's no problem to converge. Problem is because my professor, said that i have to find steady solution. I know that VOF works better for transient calculations, but Eulerian model don't treats viscosity, and Mixture model nobody recommends..

Conclusion only way is VOF - steady model, is it possible to solve it ?

[undziabundzia]

Hey, I found somthing weird on transient solution. See in attach. Meybe it's something wrong with the pressure outlets boundary...

Greetings

[undziabundzia]

Hey !

I need You guys, each advice is like gold for me - don't be shy !

I fixed problem with outlet pressures boundaries, by pressure interpolation from neighbor cells.

Now last big problem is changing velocity on fractions. As You can see, there is air at start with the 12 m/s , but it slows down(why), in the same time water fraction, which should to flow with 8 m/s, accelerates to12 m/s...

Please help me, I have new time to the monday...

Your friend Jacob

[bluebase]

Hi Jakub,

how did you define your upper ("sky") and lower ("seabed") boundaries? Do you happen to set those boundaries with constant tangential velocity? It could be that you mixed up the values of those two boundaries.

With regards,
Sebastian

[undziabundzia]

Dear Friend Sebastian

I made only one boundary condition for, like You said "sky and seabed" only one bc "mixed" , it's farfield with free slip condition. I didn't try to set tangential velocity, can You give me advice how to set this ?

If this mess, is becouse of that farfield - it means, that i have go back to meshing... hehehe i hope it is not