[Xinqiang]

Hi,

I use VOF model to simulate the liquid-vapor two phase flow. I want to get the interface curvature by udf, but I don't know how to write the equation (showed as attachment) in udf. If you know how to deal with this, could you give me some suggestion? Thanks

Xinqiang

[shiraz_man67]

I have same problem too I want to implement disjoining pressure and I need surface curvature of each cell

[vig]

You could access the curvature by the following
- Use solve>set>expert option for keeping the temporary memory from being freed [yes]

- Then Use SV_C_TMP_0 in the udf to access the value of curvature.
( This would give you the value of secondary phase curvature)

- Not always safe as this is the temporary variable and you access the values being last stored in this variable. So check before using it.

[syavash]

Originally Posted by vig

You could access the curvature by the following
- Use solve>set>expert option for keeping the temporary memory from being freed [yes]

- Then Use SV_C_TMP_0 in the udf to access the value of curvature.
( This would give you the value of secondary phase curvature)

- Not always safe as this is the temporary variable and you access the values being last stored in this variable. So check before using it.

Hi,

I suppose that there might be another way,
Saving C_VOF(c,t) into C_UDSI and extracting gradient by C_UDSI_G
Goodluck

[vig]

Volume fraction is discontinuous, therefore you would require to smoothen the volume fraction field before the calculation of gradient and curvature.

[shashank312]

Is there a way to calculate curvature apart from using the SV_C_TMP_0 macro? I'm sure there must be a way to calculate divergence of the unit normal vector to the liquid-vapor interface.

[cfd^2]

What is the real meaning of the macro SV_C_TMP_0? Does it directly access the interface curvature? I did not find details about this macro...

[cfdnemo]

Originally Posted by vig

You could access the curvature by the following
- Use solve>set>expert option for keeping the temporary memory from being freed [yes]

- Then Use SV_C_TMP_0 in the udf to access the value of curvature.
( This would give you the value of secondary phase curvature)

- Not always safe as this is the temporary variable and you access the values being last stored in this variable. So check before using it.

Is there any documentation for these macros? I couldn't find any fluent manual such as those for cell and face macros.

[dingdangmao]

Originally Posted by vig

You could access the curvature by the following
- Use solve>set>expert option for keeping the temporary memory from being freed [yes]

- Then Use SV_C_TMP_0 in the udf to access the value of curvature.
( This would give you the value of secondary phase curvature)

- Not always safe as this is the temporary variable and you access the values being last stored in this variable. So check before using it.

i have no idea about SV_C_TMP_0,can you support some realted document about how to use ?

[AlexanderZ]

probably you may use C_TMP_C0(c,t) macro to access to SV_C_TMP_0

however, I have no idea what's inside
from source

 /* SV_C_TMP_0 temporary storage, used extensively now for setting c_tmp value
     based on area average of face value. */
  SV_C_TMP_0,
  SV_C_TMP_1,                 /* temporary storage for sum of fluxes */
  SV_C_TMP_2,
  SV_C_TMP_3,                 /* temporary storage used for residual scaling */
  SV_C_TMP_V_0,               /* cell tmp vector storage for smoothed vof grad*/
  SV_F_TMP_0,                 /* temporary real on faces */
  SV_F_TMP_1,                 /* temporary real on faces */