[Shafiul]

Hi everybody,

I was running a transient simulation for Maximum number of time-step iterations of 480. Since my simulation did not converge, I wish to continue the simulation for up to 720 timesteps. I am wondering how can I do that?

I modified the definition file and set the new Max. time steps to 720. But it did not work. The simulation stopped just after one time steps showing the message " Maximum number of time-step iteration has been reached"; though it was supposed to continue until 720 time-step iterations.

Any suggestion will be highly appreciated.

[Shafiul]

More informations:

I'm using CFX V11.0.
I followed the CFX manual for "Restarting a run" and same thing happened.

I badly need help to fix it.

Thanks in advance.

[ghorrocks]

Can you post your CCL?

[Claudia]

Did you start your run with modified def-file or with the res-file? Or did you modify your res-file before starting?

[Shafiul]

Thanks for your reply. Here is the CCL:

+--------------------------------------------------------------------+
| |
| CFX Command Language for Run |
| |
+--------------------------------------------------------------------+

LIBRARY:
MATERIAL: Water
Material Description = Water (liquid)
Material Group = Water Data, Constant Property Liquids
Option = Pure Substance
Thermodynamic State = Liquid
PROPERTIES:
Option = General Material
Thermal Expansivity = 2.57E-04 [K^-1]
ABSORPTION COEFFICIENT:
Absorption Coefficient = 1.0 [m^-1]
Option = Value
END
DYNAMIC VISCOSITY:
Dynamic Viscosity = 8.899E-4 [kg m^-1 s^-1]
Option = Value
END
EQUATION OF STATE:
Density = 997.0 [kg m^-3]
Molar Mass = 18.02 [kg kmol^-1]
Option = Value
END
REFERENCE STATE:
Option = Specified Point
Reference Pressure = 1 [atm]
Reference Specific Enthalpy = 0.0 [J/kg]
Reference Specific Entropy = 0.0 [J/kg/K]
Reference Temperature = 25 [C]
END
REFRACTIVE INDEX:
Option = Value
Refractive Index = 1.0 [m m^-1]
END
SCATTERING COEFFICIENT:
Option = Value
Scattering Coefficient = 0.0 [m^-1]
END
SPECIFIC HEAT CAPACITY:
Option = Value
Specific Heat Capacity = 4181.7 [J kg^-1 K^-1]
Specific Heat Type = Constant Pressure
END
THERMAL CONDUCTIVITY:
Option = Value
Thermal Conductivity = 0.6069 [W m^-1 K^-1]
END
END
END
END
FLOW:
SOLUTION UNITS:
Angle Units = [rad]
Length Units = [in]
Mass Units = [lb]
Solid Angle Units = [sr]
Temperature Units = [R]
Time Units = [s]
END
SIMULATION TYPE:
Option = Transient
EXTERNAL SOLVER COUPLING:
Option = None
END
INITIAL TIME:
Option = Automatic
END
TIME DURATION:
Maximum Number of Timesteps = 720
Option = Maximum Number of Timesteps
END
TIME STEPS:
Option = Timesteps
Timesteps = 0.000264383 [s]
END
END
DOMAIN: Default Domain
Coord Frame = Coord 0
Domain Type = Fluid
Fluids List = Water
Location = Primitive 3D, Primitive 3D 2, Primitive 3D 3
BOUNDARY: Domain Interface 1 Side 1
Boundary Type = INTERFACE
Location = Primitive 2D 2,Primitive 2D,Primitive 2D 3
BOUNDARY CONDITIONS:
MASS AND MOMENTUM:
Option = Conservative Interface Flux
END
TURBULENCE:
Option = Conservative Interface Flux
END
END
END
BOUNDARY: Domain Interface 1 Side 2
Boundary Type = INTERFACE
Location = Primitive 2D A 3,Primitive 2D A 2,Primitive 2D A
BOUNDARY CONDITIONS:
MASS AND MOMENTUM:
Option = Conservative Interface Flux
END
TURBULENCE:
Option = Conservative Interface Flux
END
END
END
BOUNDARY: bladepre
Boundary Type = WALL
Frame Type = Rotating
Location = BLADEPREBC 2,BLADEPREBC 2 2,BLADEPREBC 2 3
BOUNDARY CONDITIONS:
WALL INFLUENCE ON FLOW:
Option = No Slip
WALL VELOCITY:
Angular Velocity = 0 [rev s^-1]
Option = Rotating Wall
END
END
END
END
BOUNDARY: bladesuc
Boundary Type = WALL
Frame Type = Rotating
Location = BLADESUCBC 2,BLADESUCBC 2 2,BLADESUCBC 2 3
BOUNDARY CONDITIONS:
WALL INFLUENCE ON FLOW:
Option = No Slip
WALL VELOCITY:
Angular Velocity = 0 [rev s^-1]
Option = Rotating Wall
END
END
END
END
BOUNDARY: hub
Boundary Type = WALL
Frame Type = Rotating
Location = HUBBC,HUBBC 2,HUBBC 3
BOUNDARY CONDITIONS:
WALL INFLUENCE ON FLOW:
Option = No Slip
WALL VELOCITY:
Angular Velocity = 0 [rev s^-1]
Option = Rotating Wall
END
END
END
END
BOUNDARY: inlet
Boundary Type = INLET
Frame Type = Rotating
Location = INLETBC,INLETBC 2,INLETBC 3
BOUNDARY CONDITIONS:
FLOW REGIME:
Option = Subsonic
END
MASS AND MOMENTUM:
Option = Cylindrical Velocity Components
Velocity Axial Component = 281.8193 [in s^-1]
Velocity Theta Component = 4.84281 [in s^-1]
Velocity r Component = -36.78481208 [in s^-1]
END
TURBULENCE:
Option = Medium Intensity and Eddy Viscosity Ratio
END
END
END
BOUNDARY: outer
Boundary Type = OPENING
Frame Type = Rotating
Location = OUTERBC,OUTERBC 2,OUTERBC 3
BOUNDARY CONDITIONS:
FLOW REGIME:
Option = Subsonic
END
MASS AND MOMENTUM:
Option = Cylindrical Velocity Components
Velocity Axial Component = 281.8193 [in s^-1]
Velocity Theta Component = 4.8428 [in s^-1]
Velocity r Component = -36.7848 [in s^-1]
END
TURBULENCE:
Option = Medium Intensity and Eddy Viscosity Ratio
END
END
END
BOUNDARY: outlet
Boundary Type = OUTLET
Frame Type = Rotating
Location = OUTLETBC,OUTLETBC 2,OUTLETBC 3
BOUNDARY CONDITIONS:
FLOW REGIME:
Option = Subsonic
END
MASS AND MOMENTUM:
Mass Flow Rate = 4541.632651 [lb s^-1]
Option = Mass Flow Rate
END
END
END
DOMAIN MODELS:
BUOYANCY MODEL:
Option = Non Buoyant
END
DOMAIN MOTION:
Angular Velocity = -31.52 [rev s^-1]
Option = Rotating
AXIS DEFINITION:
Option = Coordinate Axis
Rotation Axis = Coord 0.1
END
END
MESH DEFORMATION:
Option = None
END
REFERENCE PRESSURE:
Reference Pressure = 1 [atm]
END
END
FLUID MODELS:
COMBUSTION MODEL:
Option = None
END
HEAT TRANSFER MODEL:
Option = None
END
THERMAL RADIATION MODEL:
Option = None
END
TURBULENCE MODEL:
Option = SST
END
TURBULENT WALL FUNCTIONS:
Option = Automatic
END
END
END
DOMAIN INTERFACE: Domain Interface 1
Boundary List1 = Domain Interface 1 Side 1
Boundary List2 = Domain Interface 1 Side 2
Interface Type = Fluid Fluid
INTERFACE MODELS:
Option = General Connection
FRAME CHANGE:
Option = None
END
PITCH CHANGE:
Option = None
END
END
MESH CONNECTION:
Option = Automatic
END
END
OUTPUT CONTROL:
MONITOR OBJECTS:
MONITOR BALANCES:
Option = Full
END
MONITOR FORCES:
Option = Full
END
MONITOR PARTICLES:
Option = Full
END
MONITOR POINT: Monitor Point 1
Cartesian Coordinates = 0.0[m],0.0[m],0.0[m]
Option = Cartesian Coordinates
Output Variables List = Pressure
END
MONITOR RESIDUALS:
Option = Full
END
MONITOR TOTALS:
Option = Full
END
END
RESULTS:
File Compression Level = Default
Option = Standard
END
TRANSIENT RESULTS: Transient Results 1
File Compression Level = Default
Include Mesh = No
Option = Selected Variables
Output Variables List = Pressure
OUTPUT FREQUENCY:
Option = Every Timestep
END
END
END
SOLVER CONTROL:
ADVECTION SCHEME:
Option = High Resolution
END
CONVERGENCE CONTROL:
Maximum Number of Coefficient Loops = 30
Timescale Control = Coefficient Loops
END
CONVERGENCE CRITERIA:
Residual Target = 1.E-4
Residual Type = RMS
END
TRANSIENT SCHEME:
Option = Second Order Backward Euler
TIMESTEP INITIALISATION:
Option = Automatic
END
END
END
END
COMMAND FILE:
Version = 11.0
Results Version = 11.0
END
EXECUTION CONTROL:
INTERPOLATOR STEP CONTROL:
Runtime Priority = Standard
EXECUTABLE SELECTION:
Double Precision = Off
END
MEMORY CONTROL:
Memory Allocation Factor = 1.0
END
END
PARALLEL HOST LIBRARY:
HOST DEFINITION: amhl
Installation Root = /usr/ansys_inc/v%v/CFX
Host Architecture String = intel_ia64_linux2.4
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 = 0.050, 0.050, 0.050, 0.050, 0.050, 0.050, \
0.050, 0.050, 0.050, 0.050, 0.050, 0.050, 0.050, 0.050, 0.050, \
0.050, 0.050, 0.050, 0.050, 0.050
END
END
RUN DEFINITION:
Definition File = \
/Uns\
teady_J0751.def
Initial Values File = \
/Unsteady_J0751_002.res
Interpolate Initial Values = Off
Run Mode = Full
END
SOLVER STEP CONTROL:
Runtime Priority = Standard
EXECUTABLE SELECTION:
Double Precision = Off
END
MEMORY CONTROL:
Memory Allocation Factor = 1.0
END
PARALLEL ENVIRONMENT:
Number of Processes = 20
Start Method = SGI MPI Local Parallel
Parallel Host List = amhl*20
END
END
END

..................................
..................................
***usual calculations only for one iteration which are ignored here...
...................................
then the following message appered:

Execution terminating: maximum number of time-step iterations,
or maximum time has been reached.

Please let me know if you need further informations.

[singer1812]

Pay attention to what Claudia said. I bet you modified the def file, but restarted the res file, which remained unmodified.

Use solver manager to modify the res file and restart that one.

[vmlxb6]

Make changes to your .cfx file > Save it > Press Define run > save > Overwrite (if .def file already exist with the same name) > Check the Initial value specification check box > Browse to .res file previously created > Start run.

Your simulation will start from 480 upto 720.

[Shafiul]

Originally Posted by Claudia

Did you start your run with modified def-file or with the res-file? Or did you modify your res-file before starting?

@Claudia: I modified the def file and used the previous res file as the initial values file. I used the same approach for steady cases and it worked smoothly.

@Singer: I never modified the res file. CFX manual is not clear enough at this point. Here is what the manual says-

"To continue a previous run using the same specifications but for a further number of iterations, you can select a previously created Results File and use it as the Input File."

But your idea makes sense to me. Let me have a try.

@vmlxb6: Thanks for your suggestion.

[singer1812]

Just use solver manager to edit. Tools>Edit CFX Solve File
and choose your .res file.

When you submit the job to run, submit the .res file. It will pick up where it left off and continue with the updated changes.

[Shafiul]

It's so weird that it did not work for me. I am so frustrated now. It starts from where it left off but stops after only one iteration. I tried with several ways as follows:

1. Tools > Edit Current Results File
[modified the .res file]
Define run> Definition file : modified .res file

2. Tools > Edit Current Results File
workspace>Restart current run

3. modified .def and used the .res file as the initial values file.

And ironicaly none of them worked!! What should I do now?

Is it a license issue or I'm missing something?

[singer1812]

I am at a loss. Never had any issue with this before.

Does it take long to run? Just restart it from the beginning with the updated iteration number.

Or, make a new def file, start time is end time of old run, update iterations, and use interpolator to interpolate the old res onto the new def file.