[kevinLL]

Hello,
I want to use the level set method to investigate the multiphase flow based on openFoam software, but unfortunately failed. Could someone please give me some advice? Thank you very much!
Here is what I have done:
1. Define the level set function φ as a volScalarFields in OpenFoam
2. Give the level set function φ an initial value using the funkySetFields, as it’s a distance function from the interface. Here is the formula:
φ_0=(x-a)2+〖(y-b)〗^2+(z-c)2-r
3. Start the time loop
4. Try to solve the level set function like this:
fvScalarMatrix levelsetphiEqn
(
fvm::ddt(levelsetphi) + fvm::div(phi, levelsetphi)
);
levelsetphiEqn.solve();

5. Update the transport properties:
density: ρ=ρ_f H+ρ_g (1-H)
viscosity: μ=μ_f H+μ_g (1-H)

6. Reinitialize the level set function with the following equation:
{■(φ_τ=sign(φ_0)(1-|∇φ|)@φ(x,0)=φ_0 )┤
7. Solve the conservation equantion: ∇∙u=0
ρ Du/Dt=-∇p+ρg+∇∙τ+f_σ
8. Go to the next time step
when I use the level set method, the simulation result tends to diverge. So I wander what the matter is.
Thanks!

[moblimostafa]

Originally Posted by kevinLL

Hello,
I want to use the level set method to investigate the multiphase flow based on openFoam software, but unfortunately failed. Could someone please give me some advice? Thank you very much!
Here is what I have done:
1. Define the level set function φ as a volScalarFields in OpenFoam
2. Give the level set function φ an initial value using the funkySetFields, as it’s a distance function from the interface. Here is the formula:
φ_0=(x-a)2+〖(y-b)〗^2+(z-c)2-r
3. Start the time loop
4. Try to solve the level set function like this:
fvScalarMatrix levelsetphiEqn
(
fvm::ddt(levelsetphi) + fvm::div(phi, levelsetphi)
);
levelsetphiEqn.solve();

5. Update the transport properties:
density: ρ=ρ_f H+ρ_g (1-H)
viscosity: μ=μ_f H+μ_g (1-H)

6. Reinitialize the level set function with the following equation:
{■(φ_τ=sign(φ_0)(1-|∇φ|)@φ(x,0)=φ_0 )┤
7. Solve the conservation equantion: ∇∙u=0
ρ Du/Dt=-∇p+ρg+∇∙τ+f_σ
8. Go to the next time step
when I use the level set method, the simulation result tends to diverge. So I wander what the matter is.
Thanks!

Hi Kevin

Where you able to fix the problem you had in the implementation? How did you initialize the problem with funkysetfields? I have been trying to do so but I have been unsuccessful so far.

[wenxu]

Hi, Mostafa Mobli,

Now, I am implementing the reinitialization step. Did you succeed about this step?

Regards,
Wen

[wenxu]

Hi, could you describe the reinitialization step more clearly? I do not know how you initialize the G field. I know that FMM is one of the choice to reinitialize the distance field.

6. Reinitialize the level set function with the following equation:
{■(φ_τ=sign(φ_0)(1-|∇φ|)@φ(x,0)=φ_0 )┤

Regards,
Wen