Learning Forum

[Edrick Kusumo]

Hello,

I got this error on Fluent: "Node 0: Process 13108: Received Signal SIGSEGV" which was then followed by several instances of "999999: mpt_accept: error: accept failed: No error" and finishing with "The f1 process could not be started."

I looked this error up on the forum but most or all of them talked about using a UDF, which I did not use. Does anyone know how to fix this and/or why this happened?

For additional information about my case, I am using an eighth of a Spray G Nozzle geometry, injection (pressure inlet) pressure of 983700 Pa, outlet (pressure outlet) pressure of 98370 Pa, hydrogen gas into argon with the mixture template. The operation is in steady state and laminar w/ viscous heating is turned on. Let me know if there is any more information that I can provide.

 

 

[DrAmine]

Did that occur at initialization? Or in the middle of the run? Are you using any real gas model or customization?

[Edrick Kusumo]

It occured during initialization and I was using real gas.

I solved the problem by reducing the number of cells so it may have been a RAM related issue.

[Rob]

9 bar dP on the system? How did you initialise the flow & jet?

[Edrick Kusumo]

I'm not sure what you mean by 9 dP on the system. 

I initialized the jet with a pressure inlet at the top at 983700 Pa with an initial velocity of -0.01 m/s. The pressure outlet is the curve along the bottom hemisphere region, set at 98370 Pa. As you can see, Argon is set up for the bottom hemisphere as the ambient and hydrogen is filling up the rest. 

[Rob]

Inlet's about 9.8 bar (or I need glasses - quite possible), outlet is a touch under 1 bar. How did you initialise the jet? 

[Edrick Kusumo]

You are correct on both pressures. The initialization of the jet was initialized based on the inlet with an additional -0.01 m/s velocity in the y-axis. Hope this answers your question.

Also, I had solved this problem by reducing the mesh so it seemed to be, at least in part, a RAM issue. 

[Rob]

Possible, are there any errors or messages above the SIGSEV line? A coarser mesh can also mean you've diffused the gradient that's causing the problem, or removed a poor quality cell/region of mesh. 

[Edrick Kusumo]

There were no more errors above the SIGSEV line but there was a text file in the same folder as the case file that said "Node 0 Fatal signal raised sig = Segmentation fault." I looked up this error in the Learning Forum and someone said that it was a RAM problem, so I decided to reduce the mesh and it worked.

[Rob]

Segmentation fault often is divergence, but SIGSEV is often a lack of data somewhere it's needed. Given the configuration it could be as simple as a partition hitting a poor, or single cell. If you use the interpolation file from the coase case will the finer mesh run?