Learning Forum

[Murtala Musa]

I am trying to do a heave and roll decay test in calm sea conditions, how do I model the velocity inlet, pressure outlet, and walls boundary conditions for a calm sea state. 

[Rob]

You could use open channel, or possibly even bound the domain with walls (pressure bc for the "sky") depending on how far the walls are from the object. 

[Murtala Musa]

Thanks for the response Rob,

1) In the case I use open channel flow as you suggested, the velocity magnitude at the inlet should be zero right? 

2) How can I, then, create a report definition that plots roll and heave decay with time, Just as in the heave decay image below?
     My simulation is on a Spar cylinder hull seen in the image below, any suggestion will be appreciated. thanks!

[Rob]

Zero flow is fine. Note, the D in CFD is Dynamics so you may find converge (residuals) to be relatively poor - also review what the residuals represent. 

Have a look at the surface reports for mesh; you may not have an easy angle report but min/max may be sufficient? Unless the UDF for 6DOF can return something? 

[Murtala Musa]

"surface reports for mesh"
Please can you elaborate, Is that how I can create reports plot for the roll and heave?

[Rob]

Have a look at the Report Definitions in the Fluent solver tree. They're used in most of the tutorials so you'll find examples there. 

[Murtala Musa]

Hello rob, 

"surface reports for mesh"
Do you mean that, I should select "Mesh" from the Field Variable drop down, as seen in the image below,?

[Murtala Musa]

Okay thanks, I'll have a look.

[Murtala Musa]

Hello rob, 

"surface reports for mesh"
Do you mean that, I should select "Mesh" from the Field Variable drop down, as seen in the image below,?

[Rob]

Try it and see if it's what you want/need.