[EtaEta]

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?

[ghorrocks]

Can you post an image? And CCL would help.

[EtaEta]

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 


[ghorrocks]

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.

[EtaEta]

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

[ghorrocks]

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.

[EtaEta]

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)

[ghorrocks]

So that proves it, doesn't it? It is a post-processor rendering thing. The simulations are the same.