# CFX13 Post Periodic interface

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 December 7, 2011, 19:13 CFX13 Post Periodic interface #1 New Member   Join Date: Dec 2011 Posts: 4 Rep Power: 6 I am simulating a axial compressor rotor. I used my mesh in CFX11 and CFX 13. I waited until mass is converged for both cases. When I used CFX 11, upper periodic side and lower periodic side have same Velocity v. But, for the case with CFX 13, upper periodic side and lower periodic side have slightly different Velocity v. Especially near blade tip. What am I doing wrong?

 December 8, 2011, 02:24 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 12,714 Rep Power: 99 Can you post an image? And CCL would help.

December 8, 2011, 15:18
Here are CCL & image
#3
New Member

Join Date: Dec 2011
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I attached an axial cut of passage. It shows an unexplainable shift.

Thank you

Here is the CCL:
PHP Code:
```  +--------------------------------------------------------------------+ |                                                                    | |                    CFX Command Language for Run                    | |                                                                    | +--------------------------------------------------------------------+ LIBRARY:   MATERIAL: Air Ideal Gas     Material Description = Air Ideal Gas (constant Cp)     Material Group = Air Data, Calorically Perfect Ideal Gases     Option = Pure Substance     Thermodynamic State = Gas     PROPERTIES:       Option = General Material       EQUATION OF STATE:         Molar Mass = 28.96 [kg kmol^-1]         Option = Ideal Gas       END       SPECIFIC HEAT CAPACITY:         Option = Value         Specific Heat Capacity = 1.0044E+03 [J kg^-1 K^-1]         Specific Heat Type = Constant Pressure       END       REFERENCE STATE:         Option = Specified Point         Reference Pressure = 1 [atm]         Reference Specific Enthalpy = 0. [J/kg]         Reference Specific Entropy = 0. [J/kg/K]         Reference Temperature = 25 [C]       END       DYNAMIC VISCOSITY:         Dynamic Viscosity = 1.831E-05 [kg m^-1 s^-1]         Option = Value       END       THERMAL CONDUCTIVITY:         Option = Value         Thermal Conductivity = 2.61E-2 [W m^-1 K^-1]       END       ABSORPTION COEFFICIENT:         Absorption Coefficient = 0.01 [m^-1]         Option = Value       END       SCATTERING COEFFICIENT:         Option = Value         Scattering Coefficient = 0.0 [m^-1]       END       REFRACTIVE INDEX:         Option = Value         Refractive Index = 1.0 [m m^-1]       END     END   END END FLOW: Flow Analysis 1   SOLUTION UNITS:     Angle Units = [rad]     Length Units = [m]     Mass Units = [kg]     Solid Angle Units = [sr]     Temperature Units = [K]     Time Units = [s]   END   ANALYSIS TYPE:     Option = Steady State     EXTERNAL SOLVER COUPLING:       Option = None     END   END   DOMAIN: R1     Coord Frame = Coord 0     Domain Type = Fluid     Location = Passage     BOUNDARY: R1 Blade       Boundary Type = WALL       Frame Type = Rotating       Location = BLADE       BOUNDARY CONDITIONS:         HEAT TRANSFER:           Option = Adiabatic         END         MASS AND MOMENTUM:           Option = No Slip Wall         END         WALL ROUGHNESS:           Option = Smooth Wall         END       END     END     BOUNDARY: R1 Hub       Boundary Type = WALL       Frame Type = Rotating       Location = HUB       BOUNDARY CONDITIONS:         HEAT TRANSFER:           Option = Adiabatic         END         MASS AND MOMENTUM:           Option = No Slip Wall         END         WALL ROUGHNESS:           Option = Smooth Wall         END       END     END     BOUNDARY: R1 Inlet       Boundary Type = INLET       Frame Type = Stationary       Location = INFLOW       BOUNDARY CONDITIONS:         FLOW DIRECTION:           Option = Cylindrical Components           Unit Vector Axial Component = 1           Unit Vector Theta Component = 0           Unit Vector r Component = 0         END         FLOW REGIME:           Option = Subsonic         END         HEAT TRANSFER:           Option = Stationary Frame Total Temperature           Stationary Frame Total Temperature = 483.35 [K]         END         MASS AND MOMENTUM:           Option = Stationary Frame Total Pressure           Relative Pressure = 195.218 [kPa]         END         TURBULENCE:           Option = Medium Intensity and Eddy Viscosity Ratio         END       END     END     BOUNDARY: R1 Outlet       Boundary Type = OUTLET       Frame Type = Stationary       Location = OUTFLOW       BOUNDARY CONDITIONS:         FLOW REGIME:           Option = Subsonic         END         MASS AND MOMENTUM:           Mass Flow Rate = 0.10005 [kg s^-1]           Option = Mass Flow Rate         END       END     END     BOUNDARY: R1 Shroud       Boundary Type = WALL       Frame Type = Rotating       Location = SHROUD       BOUNDARY CONDITIONS:         HEAT TRANSFER:           Option = Adiabatic         END         MASS AND MOMENTUM:           Option = No Slip Wall           WALL VELOCITY:             Option = Counter Rotating Wall           END         END         WALL ROUGHNESS:           Option = Smooth Wall         END       END     END     BOUNDARY: R1 to R1 Internal Side 1       Boundary Type = INTERFACE       Location = SHROUD TIP GGI SIDE 1       BOUNDARY CONDITIONS:         HEAT TRANSFER:           Option = Conservative Interface Flux         END         MASS AND MOMENTUM:           Option = Conservative Interface Flux         END         TURBULENCE:           Option = Conservative Interface Flux         END       END     END     BOUNDARY: R1 to R1 Internal Side 2       Boundary Type = INTERFACE       Location = SHROUD TIP GGI SIDE 2       BOUNDARY CONDITIONS:         HEAT TRANSFER:           Option = Conservative Interface Flux         END         MASS AND MOMENTUM:           Option = Conservative Interface Flux         END         TURBULENCE:           Option = Conservative Interface Flux         END       END     END     BOUNDARY: R1 to R1 Periodic 1 Side 1       Boundary Type = INTERFACE       Location = PER1       BOUNDARY CONDITIONS:         HEAT TRANSFER:           Option = Conservative Interface Flux         END         MASS AND MOMENTUM:           Option = Conservative Interface Flux         END         TURBULENCE:           Option = Conservative Interface Flux         END       END     END     BOUNDARY: R1 to R1 Periodic 1 Side 2       Boundary Type = INTERFACE       Location = PER2       BOUNDARY CONDITIONS:         HEAT TRANSFER:           Option = Conservative Interface Flux         END         MASS AND MOMENTUM:           Option = Conservative Interface Flux         END         TURBULENCE:           Option = Conservative Interface Flux         END       END     END     DOMAIN MODELS:       BUOYANCY MODEL:         Option = Non Buoyant       END       DOMAIN MOTION:         Alternate Rotation Model = true         Angular Velocity = 26286 [rev min^-1]         Option = Rotating         AXIS DEFINITION:           Option = Coordinate Axis           Rotation Axis = Coord 0.1         END       END       MESH DEFORMATION:         Option = None       END       REFERENCE PRESSURE:         Reference Pressure = 0 [atm]       END     END     FLUID DEFINITION: Air Ideal Gas       Material = Air Ideal Gas       Option = Material Library       MORPHOLOGY:         Option = Continuous Fluid       END     END     FLUID MODELS:       COMBUSTION MODEL:         Option = None       END       HEAT TRANSFER MODEL:         Include Viscous Work Term = On         Option = Total Energy       END       THERMAL RADIATION MODEL:         Option = None       END       TURBULENCE MODEL:         Option = SST       END       TURBULENT WALL FUNCTIONS:         High Speed Model = On         Option = Automatic       END     END   END   DOMAIN INTERFACE: R1 to R1 Internal     Boundary List1 = R1 to R1 Internal Side 1     Boundary List2 = R1 to R1 Internal Side 2     Interface Type = Fluid Fluid     INTERFACE MODELS:       Option = General Connection       FRAME CHANGE:         Option = None       END       MASS AND MOMENTUM:         Option = Conservative Interface Flux         MOMENTUM INTERFACE MODEL:           Option = None         END       END       PITCH CHANGE:         Option = None       END     END     MESH CONNECTION:       Option = GGI     END   END   DOMAIN INTERFACE: R1 to R1 Periodic 1     Boundary List1 = R1 to R1 Periodic 1 Side 1     Boundary List2 = R1 to R1 Periodic 1 Side 2     Interface Type = Fluid Fluid     INTERFACE MODELS:       Option = Rotational Periodicity       AXIS DEFINITION:         Option = Coordinate Axis         Rotation Axis = Coord 0.1       END     END     MESH CONNECTION:       Option = GGI     END   END   OUTPUT CONTROL:     MONITOR OBJECTS:       MONITOR BALANCES:         Option = Full       END       MONITOR FORCES:         Option = Full       END       MONITOR PARTICLES:         Option = None       END       MONITOR POINT: outletpressure         Expression Value = ave(Pressure)@R1 Outlet         Option = Expression       END       MONITOR RESIDUALS:         Option = Full       END       MONITOR TOTALS:         Option = Full       END     END     RESULTS:       Extra Output Variables List = Mach Number,Total Pressure,Total \         Pressure in Stn Frame,Total Temperature,Total Temperature in Stn \         Frame,Velocity in Stn Frame,Vorticity,Wall Shear,Temperature,Total \         Enthalpy in Stn Frame,Rotation Velocity       File Compression Level = Default       Option = Standard     END   END   SOLVER CONTROL:     Turbulence Numerics = First Order     ADVECTION SCHEME:       Option = High Resolution     END     CONVERGENCE CONTROL:       Length Scale Option = Conservative       Maximum Number of Iterations = 500       Minimum Number of Iterations = 1       Timescale Control = Auto Timescale       Timescale Factor = 1     END     CONVERGENCE CRITERIA:       Residual Target = 0.000001       Residual Type = MAX     END     DYNAMIC MODEL CONTROL:       Global Dynamic Model Control = On     END   END END COMMAND FILE:   Version = 13.0   Results Version = 13.0 END SIMULATION CONTROL:   EXECUTION CONTROL:     EXECUTABLE SELECTION:       Double Precision = Off     END     INTERPOLATOR STEP CONTROL:       Runtime Priority = Standard       MEMORY CONTROL:         Memory Allocation Factor = 1.0       END     END     PARALLEL HOST LIBRARY:       HOST DEFINITION: eTaEta         Remote Host Name = EtaEta         Installation Root = C:\Program Files\ANSYS Inc\v%v\CFX         Host Architecture String = winnt-amd64       END     END     PARTITIONER STEP CONTROL:       Multidomain Option = Independent Partitioning       Runtime Priority = Standard       EXECUTABLE SELECTION:         Use Large Problem Partitioner = Off       END       MEMORY CONTROL:         Memory Allocation Factor = 1.0       END       PARTITIONING TYPE:         MeTiS Type = k-way         Option = MeTiS         Partition Size Rule = Automatic         Partition Weight Factors = 0.50000, 0.50000       END     END     RUN DEFINITION:       Solver Input File = \         C:\Users\EtaEta\Base\base_v1_m_010005_new_002.res       Run Mode = Full     END     SOLVER STEP CONTROL:       Runtime Priority = Standard       MEMORY CONTROL:         Memory Allocation Factor = 1.0       END       PARALLEL ENVIRONMENT:         Number of Processes = 2         Start Method = HP MPI Local Parallel         Parallel Host List = eTaEta*2       END     END   END END  ```
Attached Images
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 December 8, 2011, 17:23 #4 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 12,714 Rep Power: 99 Can you show what the problem is? It is not clear. But if you are talking about the interfaces then that is just a post processing rendering thing. The underlying simulation should be the same. View both simulations with the same post processor and it should look the same.

 December 8, 2011, 17:46 #5 New Member   Join Date: Dec 2011 Posts: 4 Rep Power: 6 If you look to the picture, you can see there is a clear shift in the middle. Normally, two periodic interfaces should coincide and have same values. It is a not a interface problem. I think there is a tolerance in the periodic side, whose default value is increased when switching from CFX 11 to CFX 13. Thanks

 December 8, 2011, 17:51 #6 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 12,714 Rep Power: 99 As I said, I suspect it is a post processing issue. Have you compared the two runs on the same post processor? It might be rendered differently between V11 and V13.

 December 8, 2011, 17:57 #7 New Member   Join Date: Dec 2011 Posts: 4 Rep Power: 6 Yes, I did. CFX 11 run has same velocities at periodic boundary in CFX 13 Post. But still, the run from CFX 13, in CFX 13 Post, shows slightly different velocities. (CFX 11 Post does not accept the runs of CFX 13)

 December 8, 2011, 18:15 #8 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 12,714 Rep Power: 99 So that proves it, doesn't it? It is a post-processor rendering thing. The simulations are the same.

 Tags cfx post 11, cfx post 13, periodic bc, rotor

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