Difficulties with setup of interFOAM VOF - Boundary Conditions?
 

Hi all,

I've been trying to simulate water & air flow past a yacht in a domain with an initialed volume of fluid, as illustrated below.

However, when I simulate this I get peculiar behavior at the inlet patch, wherein the water seems to climb the boundaries of the domain in the opposite direction of fluid flow, as shown below.

I've taken the yacht out of the simulation in an effort to speed up simulation times while I rectify this. I've tried altering patch types, positions (i.e. the air inlet/outlet being the top surface opposed to the side surfaces), differing flow velocities, and initializing the volume of fluid with a uniform velocity matching the inlet boundary condition. All of my simulation iterations seem to demonstrate the same behavior.

Is anyone able to offer any suggestions on how to correct this?

I've attached my case below for your reference.

https://drive.google.com/open?id=1hF...KbXubSQNJMM3a_

Thanks and best regards

Attachment 62719

Attachment 62720
https://mega.nz/#!HmJFWKYD

BCs are wrong. I would suggest you to take a look at the wave tutorial of OF, here.

Moreover, there is no need breakup all the domain like the way you did. If you don't want to use the wave BC you might want to divide the inlet only not outlet and sides. Also, because you're using interFoam you should use fixedFluxPressure instead of zeroGradient for pressure and pressureInletOutLetVelocity for velocity for the boundaries where you use totalPressure for pressure.

The general idea is that in this kind of problems you should specify velocity at the inlet (fixedValue for velocity and fixedFluxPressure for pressure) and pressure at the outlet (totalPressure for pressure and pressureInletOutLetVelocity for velocity).

fixedFluxPressure
 

Can you please explain me about 'fixedFluxPressure' ?, why do i need to apply that instead of zeroGradient in interFoam? Please enlight me on this.

You can find good explanations here.