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Topics - pitney1

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16
When using CFX 10.0 Solver why are my particle tracks so short when the injection velocity is low? The Particle Fate Diagnostics indicate "Exceeded time limit".

17
How do I set a particle injection rate at a frequency less other then every time step in a transient simulation?

18
What does a local timestep factor (LTF) in the CFX solver mean?

19
CFX / Simulating heat transfer in a closed room
« on: May 11, 2012, 10:35:58 PM »
How can I get good convergence when simulating heat transfer in a closed room?

20
How can I visualize the position of a surface level in CFX Post 10.0 for a free surface flow?

21
CFX / Newtons method failed to converge in 100 iterations.
« on: May 11, 2012, 10:32:40 PM »
The Solver crahes with no helpful error, but does give the following warning on the iteration before failure: +--------------------------------------------------------------------+ | ****** Notice ****** | | Newtons method failed to converge in 100 iterations. This | | occurred while computing the following variable: | | | | Variable Name : Total Temperature | | Location Name : sparks | | Mesh location : VERTICES | | Mesh entity : | | Last 3 Changes : 1.26616E+03 1.26326E+03 1.26767E+03 | | Tolerance : 1.0000E-02 | | | | The Newton iteration was diverging. The solver will continue | | with the variable field as it was on the final iteration. If | | this situation continues you might try decreasing the Netwon | | iteration under relaxation factor. This can be changed by | | setting one of the following parameters: | | | | Temperature : "Constitutive Relation Under Relaxation" | | Pressure : "Newton Pressure Under Relaxation" | | | | for your mixture using the definition file editor. | +--------------------------------------------------------------------+

22
How should you set up different wall boundary conditions for different fluids in a CFX 10.0 multiphase calculation?

23
CFX / Error: Cannot calculate total enthalpy
« on: May 11, 2012, 10:27:07 PM »
For a case with more than one continuous phase, the CFX Solver stops right at the start of the calculation with the following error:

Cannot calculate total enthalpy.
+--------------------------------------------------------------------+
| Writing crash recovery file |
+--------------------------------------------------------------------+

+--------------------------------------------------------------------+
| ERROR #001100279 has occurred in subroutine ErrAction. |
| Message: |
| Stopped in routine CAL_ENTHTOT |
| |
| |
| |
+--------------------------------------------------------------------+

24
How can you set the thermal conductivity in a porous domain in CFX 11.0?

Help.

25
On Windows 64bit, CFX-Pre crashes when creating a domain interface at a fluid-solid interface in a model including radiation with the error: SEVERE Operation failed. Insufficient memory. PROBLEM: This is due to incorrect logic in the code leading to a memory access violation.

26
How does the multiphase model handle the wall contact of several phases? i.e. when an oil layer builds up on the wall, how is this phenomenon modeled and what stimulates further buildup of oil and controls the behavior of the layer in general?

27
CFX / How the Herschel-Bulkley model works in CFX?
« on: May 11, 2012, 10:09:06 PM »
I am interested in how the Herschel-Bulkley model works in CFX. When I do the calculations by hand, I have to explicitly find the yield surface in the fluid then divide my region into two pieces for the velocity calculations. How does CFX calculate the yield surface, if at all? The Herschel-Bulkley equation gives an infinite viscosity for parts of the flow. Having an infinite viscosity would give numerical problems, so what modifications to the Herschel-Bulkley equations have been made to make the numerical solution tractable? How are the material parameters, yield stress and min/max shear strain rate values, used?

28
CFX / Model beam deflection by stresses
« on: May 11, 2012, 10:06:09 PM »
I have a structural problem that I want to run which involves a beam that is deflected by stresses unrelated to fluid forces. To get this deflection, I am going to solve a steady-state structural problem in ANSYS. I would then like to do a standalone CFD simulation for flow around the beam. What is the best way to get the mesh for the deformed beam into the CFD calculation?

29
How do I set the pressure profile at a vertical pressure boundary for free surface flow?

30
Is there a way to specify surface roughness while using the SST model? Is it possible to use scalable wall functions with these turbulence models?


Pages: 1 [2] 3 4