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October 28, 2021, 11:06 
Error SIGSEGV using VOF and UDF

#1  
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Jorge Rodríguez
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Hello, I am having a SIGSEGV error when trying to use a UDF that I created for evaporationcondensation limited by the vapor pressure. I am using a gas phase (primary) using the methylalcoholair template with density set up as ideal gas and a liquid phase combine with methylalcoholliquid and waterliquid (with density Volume Weight Mixing Law).
I manage to compile the UDF without any warning and, in order to test the UDF, I decide to work with a closed and small 2D plane with a Pressure Operation around 10 MPa and a temperature of 450 K (which are nearly similar to the operation condition I will work with this UDF). I design the UDF using the template ANSYS provided in their manual as a template and also have that one in order to discard possible errors. Either, by using my UDF and the one in the manual, I still have the SIGSEGV warning. ================================================== ============================ Node 0: Process 13728: Received signal SIGSEGV. ================================================== ============================ The fl process could not be started. The UDF I created is the following: Quote:
Everytime I got the same error. 

October 29, 2021, 01:04 

#2 
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Alexander
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you have an equation for 3D case, but running it in 2D
change to Code:
#if RP_3D urelz = C_W(c,tp)  C_W(c,ts); #endif urel = sqrt(urelx*urelx + urely*urely ); /*relative #if RP_3D urel = sqrt(urelx*urelx + urely*urely + urelz*urelz); /*relative #endifvelocity*/
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October 29, 2021, 10:19 

#3  
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Jorge Rodríguez
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Quote:
Thanks anyway for the help. Much appreciate. 

October 29, 2021, 10:50 

#4  
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Jorge Rodríguez
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Quote:
EDIT: I tried with a few if for the secondary phase and it still didn't work. 

October 29, 2021, 14:55 

#5 
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Maybe you forgot to enable the energy equation?
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"The UDF library you are trying to load (libudf) is not compiled for parallel use on the current platform" is NOT the error after compiling. It is the error after loading. To see compiler errors, look at your screen after you click "build". 

October 29, 2021, 15:22 

#6 
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Jorge Rodríguez
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It can't be. Energy equation is enable.
EDIT: I just realize Fluent become buggy just after the error is presented. Everywhere I click the text is all over the place. Captura.jpg 

October 31, 2021, 18:42 

#7 
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Alexander
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problem could be here
Code:
real OP = RP_Get_Float("operatingpressure"); /*OPERATING PRESSURE*/ Code:
real OP = RP_Get_Real("operatingpressure"); /*OPERATING PRESSURE*/
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November 2, 2021, 11:34 

#8  
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Jorge Rodríguez
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Quote:
I use the Visual Studio compiler because the buildin doesn't work properly, so I doesn't know if it may be related. 

November 2, 2021, 23:59 

#9 
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Alexander
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try simplified udf with constant output
Code:
#include "udf.h" DEFINE_HET_RXN_RATE(user_evap_condens_react, c, t, hr, mw, yi, rr, rr_t) { *rr = constant value here; } }
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November 3, 2021, 10:36 

#10  
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Jorge Rodríguez
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Quote:
This is the UDF: Quote:
Stabilizing temperature to enhance linear solver robustness. Stabilizing temperature using GMRES to enhance linear solver robustness. Divergence detected in AM Error at Node 3: floating point exception Error at Node 1: floating point exception Error at Node 2: floating point exception Error at Node 0: floating point exception G solver: temperature Divergence detected in AMG solver: temperature Divergence detected in AMG solver: temperature Divergence detected in AMG solver: temperature Error at host: floating point exception Error: floating point exception Error Object: #f Tried with both, stationary and transient model. 

November 3, 2021, 23:45 

#11 
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Alexander
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when did you get this error, on the very first time step?
you may try to decrease timestep. make it small enough. check your mesh quality
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November 4, 2021, 08:56 

#12  
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Jorge Rodríguez
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Quote:
Quote:
Btw, the error happens in the first iteration. EDIT: Tried to refine mesh from 0,5 mm to 0,1 mm element size. It didn't work. 

November 5, 2021, 01:22 

#13 
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Alexander
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you may try to run same case but with simplified heating rate
Code:
#include "udf.h" DEFINE_HET_RXN_RATE(user_evap_condens_react, c, t, hr, mw, yi, rr, rr_t) { *rr = constant value here; } }
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November 5, 2021, 10:34 

#14  
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Jorge Rodríguez
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Quote:
Stabilizing xmomentum to enhance linear solver robustness. Stabilizing xmomentum using GMRES to enhance linear solver robustness. Divergence detected in AMG solver: xmomentum Stabilizing ymomentum to enhance linear solver robust Error at Node 3: floating point exception Error at Node 1: floating point exception Error at Node 2: floating point exception ness. Error at Node 0: floating point exception Stabilizing ymomentum using GMRES to enhance linear solver robustness. Divergence detected in AMG solver: ymomentum Stabilizing pressure correction to enhance linear solver robustness. Stabilizing pressure correction using GMRES to enhance linear solver robustness. Divergence detected in AMG solver: pressure correction Stabilizing k to enhance linear solver robustness. Stabilizing k using GMRES to enhance linear solver robustness. Divergence detected in AMG solver: k Stabilizing epsilon to enhance linear solver robustness. Stabilizing epsilon using GMRES to enhance linear solver robustness. Divergence detected in AMG solver: epsilon Stabilizing vaporspecies0 to enhance linear solver robustness. Stabilizing vaporspecies0 using GMRES to enhance linear solver robustness. Divergence detected in AMG solver: vaporspecies0 Stabilizing vaporspecies1 to enhance linear solver robustness. Stabilizing vaporspecies1 using GMRES to enhance linear solver robustness. Divergence detected in AMG solver: vaporspecies1 Stabilizing vaporspecies2 to enhance linear solver robustness. Stabilizing vaporspecies2 using GMRES to enhance linear solver robustness. Divergence detected in AMG solver: vaporspecies2 Stabilizing vaporspecies3 to enhance linear solver robustness. Stabilizing vaporspecies3 using GMRES to enhance linear solver robustness. Divergence detected in AMG solver: vaporspecies3 Stabilizing vaporspecies4 to enhance linear solver robustness. Stabilizing vaporspecies4 using GMRES to enhance linear solver robustness. Divergence detected in AMG solver: vaporspecies4 Stabilizing liquidspecies0 to enhance linear solver robustness. Stabilizing liquidspecies0 using GMRES to enhance linear solver robustness. Divergence detected in AMG solver: liquidspecies0 Stabilizing temperature to enhance linear solver robustness. Stabilizing temperature using GMRES to enhance linear solver robustness. Divergence detected in AMG solver: temperature Stabilizing vof1 to enhance linear solver robustness. Stabilizing vof1 using GMRES to enhance linear solver robustness. Divergence detected in AMG solver: vof1 Divergence detected in AMG solver: xmomentum Divergence detected in AMG solver: ymomentum Divergence detected in AMG solver: pressure correction Divergence detected in AMG solver: k Divergence detected in AMG solver: epsilon Divergence detected in AMG solver: vaporspecies0 Divergence detected in AMG solver: vaporspecies1 Divergence detected in AMG solver: vaporspecies2 Divergence detected in AMG solver: vaporspecies3 Divergence detected in AMG solver: vaporspecies4 Divergence detected in AMG solver: liquidspecies0 Divergence detected in AMG solver: temperature Divergence detected in AMG solver: vof1 Divergence detected in AMG solver: xmomentum Divergence detected in AMG solver: ymomentum Divergence detected in AMG solver: pressure correction Divergence detected in AMG solver: k Divergence detected in AMG solver: epsilon Divergence detected in AMG solver: vaporspecies0 Divergence detected in AMG solver: vaporspecies1 Divergence detected in AMG solver: vaporspecies2 Divergence detected in AMG solver: vaporspecies3 Divergence detected in AMG solver: vaporspecies4 Divergence detected in AMG solver: liquidspecies0 Divergence detected in AMG solver: temperature Divergence detected in AMG solver: vof1 Divergence detected in AMG solver: xmomentum Divergence detected in AMG solver: ymomentum Divergence detected in AMG solver: pressure correction Divergence detected in AMG solver: k Divergence detected in AMG solver: epsilon Divergence detected in AMG solver: vaporspecies0 Divergence detected in AMG solver: vaporspecies1 Divergence detected in AMG solver: vaporspecies2 Divergence detected in AMG solver: vaporspecies3 Divergence detected in AMG solver: vaporspecies4 Divergence detected in AMG solver: liquidspecies0 Divergence detected in AMG solver: temperature Divergence detected in AMG solver: vof1 Error at host: floating point exception Error: floating point exception Error Object: #f I define a constant around 1.5*1e(n), varying the n value from 3 to 10. 

November 8, 2021, 00:17 

#15 
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Alexander
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I have no experience in condensation/evaporation simulations
but for me this error means, you do probably have problems with case settings (boundary conditions, may be material properties, mesh, others) as you are using simplified UDF. If you don't have any other thoughts you may try to simplify your case, may be start with just 2 species, find convergence and go step but step to your real case.
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