[treeman1]

Hi,
I am a learner of Fluent. I encounter a problem and cannot handle it. Please help me.

I am dealing with a blast wave problem, but error occurs during calculation.
absolute pressure limited to 1
temperature limited to 1
absolute pressure limited to 5e+10
temperature limited to 5e+6
( I have increased the upper limit)


My domian is a 1/8 sphere.

I set operating pessure to 0, so all pressures in inlet and outlet are absolute pressures.
The inlet is the small spheric surface and the type is pressure-inlet. Profile is used to input the pressure history.

Outlet is the big spheric surface with gauge pressure to be 101325.
I initialize the solver by hand with 101325pa in the domain.
Material is ideal gas.
Model settings are inviscid and energy on.
Sovler is density-based, explicit, first upwind.
Time step is 1e-6s. And the grid is smoothed over 0.5 for orthogonal quality.
I have no idea why this error arise. Please help me. Many thanks!

[treeman1]

I used contour to find out in which area the temperature is limited to 1.

And I found that it's the cells just close to the centre of the pressure-inlet. I checked the profile I input and cannot find any error in it.
Do anyone know what's going wrong with my case?
Hope someone could help me. OTZ

Originally Posted by treeman1

Hi,
I am a learner of Fluent. I encounter a problem and cannot handle it. Please help me.

I am dealing with a blast wave problem, but error occurs during calculation.
absolute pressure limited to 1
temperature limited to 1
absolute pressure limited to 5e+10
temperature limited to 5e+6
( I have increased the upper limit)


My domian is a 1/8 sphere.

I set operating pessure to 0, so all pressures in inlet and outlet are absolute pressures.
The inlet is the small spheric surface and the type is pressure-inlet. Profile is used to input the pressure history.

Outlet is the big spheric surface with gauge pressure to be 101325.
I initialize the solver by hand with 101325pa in the domain.
Material is ideal gas.
Model settings are inviscid and energy on.
Sovler is density-based, explicit, first upwind.
Time step is 1e-6s. And the grid is smoothed over 0.5 for orthogonal quality.
I have no idea why this error arise. Please help me. Many thanks!

[arep_24]

have you solve this problem ??

[pakk]

This only shows that the simulation diverged. It can have many different reasons, and the reason for treeman1 is probably not the same as for you.

In my experience, mostly it is a bad mesh that causes divergence, so that is the first thing I would look at. (Examine the mesh in the region where you see extremely high/low values in your solution). But like I said, it can have many different reasons.

[LuckyTran]

Has anyone tried laminar w/ energy to see if it still diverges? It might be a problem with the inviscid solver.