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August 28, 2010, 06:50 |
sliding mesh problem in CFX
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#1 |
Senior Member
Saima
Join Date: Apr 2009
Location: Canada
Posts: 185
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Hi All,
There is a tutorial in Fluent "Tutorial 11: Using Sliding Meshes " 2D Tutorial. In fluent problem Fluid phase Velosity (which is given in Fluent around y= -Vx) imposeed under Setup => Cell Zone Conditions. I want to do same in CFX but i have not foung Fluid Translation in CFX. How can i do it? CFX just have "Rotaion" and stationary" option in "domain"option. I dont want to give rotaion brcause i am working on airfoil. Please let me know. Thank you, Last edited by Saima; August 28, 2010 at 08:14. |
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August 29, 2010, 18:59 |
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#2 |
Super Moderator
Glenn Horrocks
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To do anything but rotation you need to use general moving mesh. Translating mesh is meant to be a beta feature but I have never used it and cannot guarantee it works - talk to CFX support if this is of interest.
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April 15, 2014, 13:13 |
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#3 |
Senior Member
ali
Join Date: Oct 2009
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Saima,
Did you succeed to translate the mesh? I am looking into almost the same problem. |
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April 28, 2014, 12:16 |
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#4 |
Senior Member
ali
Join Date: Oct 2009
Posts: 318
Rep Power: 18 |
Saima? did u solve it?
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April 28, 2014, 18:16 |
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#5 |
Super Moderator
Glenn Horrocks
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These posts are 4 years old, it is unlikely you will get any response except from the tragics like me
But my post from 4 years ago still stands - use moving mesh to do it. |
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April 28, 2014, 19:37 |
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#6 |
Senior Member
ali
Join Date: Oct 2009
Posts: 318
Rep Power: 18 |
Glenn,
In all of the posts that there has been some issue with translational mesh motion you said that it is possible and yes it is. But there is one problem. you see in my case there are two domains, one stationary, the other one is supposed to translate(not rotating, translating) for the time steps that the interfaces of the two domains are not overlapping 100%, the solver assumes there is a wall for the non-overlapping area. Unlike the "transient rotor stator" interface. It seems that CFX can only do the sliding mesh for rotational cases not translational cases. Now do you have any knowledge that this problem can be overcome. Maybe I can use CFX to implement translationan sliding mesh?? Thanks, Ali |
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April 28, 2014, 19:57 |
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#7 |
Super Moderator
Glenn Horrocks
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This interface connecting a domain with moving mesh (for translational motion) to a stationary domain works fine. You need to use transient rotor/stator interface setting.
CFX can handle translational interfaces fine. It is not restricted to rotational interfaces. |
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April 29, 2014, 10:56 |
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#8 |
Senior Member
ali
Join Date: Oct 2009
Posts: 318
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Are you sure? Have you done it yourself? Because when I do that I receive an error. Also When I specify transient rotor-stator interface it asks for the axis of rotation.
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April 29, 2014, 15:11 |
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#9 |
Senior Member
Edmund Singer P.E.
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We are sure. Have done it thousands of times. What error are you getting? What kind of behavior do you want for non-overlapping interfaces?
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April 29, 2014, 17:58 |
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#10 |
Senior Member
ali
Join Date: Oct 2009
Posts: 318
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This is the error that I get.
+--------------------------------------------------------------------+ | ERROR #004100018 has occurred in subroutine FINMES.| | Message: | | Fatal overflow in linear solver. | +--------------------------------------------------------------------+ Here I also have attached the CCL. Please take a look. Thanks, Last edited by alinik; April 29, 2014 at 17:58. Reason: forgot to attach |
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April 29, 2014, 17:59 |
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#11 |
Senior Member
ali
Join Date: Oct 2009
Posts: 318
Rep Power: 18 |
# State file created: 2014/04/29 15:32:12
# CFX-15.0 build 2013.10.10-08.49-130242 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 = Transient EXTERNAL SOLVER COUPLING: Option = None END INITIAL TIME: Option = Automatic with Value Time = 0 [s] END TIME DURATION: Option = Total Time Total Time = 1.5 [s] END TIME STEPS: Option = Timesteps Timesteps = 0.005 [s] END END DOMAIN: Default Domain Coord Frame = Coord 0 Domain Type = Fluid Location = BODY BOUNDARY: Domain Interface 1 Side 1 Boundary Type = INTERFACE Location = PER_1 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END MESH MOTION: Option = Conservative Interface Flux END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: Domain Interface 1 Side 2 Boundary Type = INTERFACE Location = PER_2 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END MESH MOTION: Option = Conservative Interface Flux END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: Domain Interface 2 Side 1 Boundary Type = INTERFACE Location = INLET BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END MESH MOTION: Option = Unspecified END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: out Boundary Type = OUTLET Location = OUTLER BOUNDARY CONDITIONS: FLOW REGIME: Option = Subsonic END MASS AND MOMENTUM: Option = Static Pressure Relative Pressure = 0 [Pa] END MESH MOTION: Option = Stationary END END END BOUNDARY: pressure surface Boundary Type = WALL Location = PS BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = No Slip Wall Wall Velocity Relative To = Mesh Motion END MESH MOTION: Option = Stationary END WALL ROUGHNESS: Option = Smooth Wall END END END BOUNDARY: suction suface Boundary Type = WALL Location = SS BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = No Slip Wall Wall Velocity Relative To = Mesh Motion END MESH MOTION: Option = Stationary END WALL ROUGHNESS: Option = Smooth Wall END END END BOUNDARY: symmetric back Boundary Type = SYMMETRY Location = SYM1 BOUNDARY CONDITIONS: MESH MOTION: Option = Unspecified END END END BOUNDARY: symmetric front Boundary Type = SYMMETRY Location = SYM2 BOUNDARY CONDITIONS: MESH MOTION: Option = Unspecified END END END DOMAIN MODELS: BUOYANCY MODEL: Option = Non Buoyant END DOMAIN MOTION: Option = Stationary END MESH DEFORMATION: Displacement Relative To = Previous Mesh Option = Regions of Motion Specified MESH MOTION MODEL: Option = Displacement Diffusion MESH STIFFNESS: Option = Increase near Small Volumes Stiffness Model Exponent = 10 REFERENCE VOLUME: Option = Mean Control Volume END END END END REFERENCE PRESSURE: Reference Pressure = 1 [atm] END END FLUID DEFINITION: Fluid 1 Material = Air at 25 C Option = Material Library MORPHOLOGY: Option = Continuous Fluid END END FLUID MODELS: COMBUSTION MODEL: Option = None END HEAT TRANSFER MODEL: Option = None END THERMAL RADIATION MODEL: Option = None END TURBULENCE MODEL: Option = k omega END TURBULENT WALL FUNCTIONS: Option = Automatic END END END DOMAIN: Domain 1 Coord Frame = Coord 0 Domain Type = Fluid Location = BODY 2 BOUNDARY: Domain Interface 2 Side 1 1 Boundary Type = INTERFACE Location = FAM2 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END MESH MOTION: Option = Unspecified END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: Domain Interface 3 Side 1 Boundary Type = INTERFACE Location = PER1 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END MESH MOTION: Option = Conservative Interface Flux END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: Domain Interface 3 Side 2 Boundary Type = INTERFACE Location = PER2 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END MESH MOTION: Option = Conservative Interface Flux END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: in Boundary Type = INLET Location = FAM1 BOUNDARY CONDITIONS: FLOW REGIME: Option = Subsonic END MASS AND MOMENTUM: Option = Cartesian Velocity Components U = Vinx V = Viny W = 0 [m s^-1] END MESH MOTION: Option = Stationary END TURBULENCE: Fractional Intensity = 0.019 Option = Intensity and Auto Compute Length END END END BOUNDARY: rod 1 Boundary Type = WALL Location = ROD1,ROD2 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = No Slip Wall Wall Velocity Relative To = Mesh Motion END MESH MOTION: Option = Stationary END WALL ROUGHNESS: Option = Smooth Wall END END END BOUNDARY: sym 1 Boundary Type = SYMMETRY Location = SYM1 2 BOUNDARY CONDITIONS: MESH MOTION: Option = Unspecified END END END BOUNDARY: sym 2 Boundary Type = SYMMETRY Location = SYM2 2 BOUNDARY CONDITIONS: MESH MOTION: Option = Unspecified END END END DOMAIN MODELS: BUOYANCY MODEL: Option = Non Buoyant END DOMAIN MOTION: Option = Stationary END MESH DEFORMATION: Displacement Relative To = Previous Mesh Option = Regions of Motion Specified MESH MOTION MODEL: Option = Displacement Diffusion MESH STIFFNESS: Option = Increase near Small Volumes Stiffness Model Exponent = 2.0 REFERENCE VOLUME: Option = Mean Control Volume END END END END REFERENCE PRESSURE: Reference Pressure = 1 [atm] END END FLUID DEFINITION: Fluid 1 Material = Air at 25 C Option = Material Library MORPHOLOGY: Option = Continuous Fluid END END FLUID MODELS: COMBUSTION MODEL: Option = None END HEAT TRANSFER MODEL: Option = None END THERMAL RADIATION MODEL: Option = None END TURBULENCE MODEL: Option = k omega END TURBULENT WALL FUNCTIONS: Option = Automatic END END SUBDOMAIN: Subdomain 1 Coord Frame = Coord 0 Location = BODY 2 MESH MOTION: Option = Specified Displacement DISPLACEMENT: Displacement X Component = 00 [m] Displacement Y Component = 0.1 [m]*Time This Run/1 [s] Displacement Z Component = 0 [m] Option = Cartesian Components END 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 = Translational Periodicity MASS AND MOMENTUM: Option = Conservative Interface Flux MOMENTUM INTERFACE MODEL: Option = None END END END MESH CONNECTION: Option = GGI END END DOMAIN INTERFACE: Domain Interface 2 Boundary List1 = Domain Interface 2 Side 1 1 Boundary List2 = Domain Interface 2 Side 1 Interface Type = Fluid Fluid INTERFACE MODELS: Option = General Connection FRAME CHANGE: Option = Transient Rotor Stator END MASS AND MOMENTUM: Option = Conservative Interface Flux MOMENTUM INTERFACE MODEL: Option = None END END PITCH CHANGE: Option = Automatic AXIS DEFINITION: Option = Coordinate Axis Rotation Axis = Coord 0.3 END END END MESH CONNECTION: Option = GGI END END DOMAIN INTERFACE: Domain Interface 3 Boundary List1 = Domain Interface 3 Side 1 Boundary List2 = Domain Interface 3 Side 2 Interface Type = Fluid Fluid INTERFACE MODELS: Option = Translational Periodicity MASS AND MOMENTUM: Option = Conservative Interface Flux MOMENTUM INTERFACE MODEL: Option = None END END END MESH CONNECTION: Option = Automatic END END INITIALISATION: Option = Automatic INITIAL CONDITIONS: Velocity Type = Cartesian CARTESIAN VELOCITY COMPONENTS: Option = Automatic with Value U = 3.074848454 [m s^-1] V = -2.153036289 [m s^-1] W = 0 [m s^-1] END STATIC PRESSURE: Option = Automatic with Value Relative Pressure = 20 [Pa] END TURBULENCE INITIAL CONDITIONS: Option = Medium Intensity and Eddy Viscosity Ratio END END END OUTPUT CONTROL: MONITOR OBJECTS: MONITOR BALANCES: Option = Full END MONITOR FORCES: Option = Full END MONITOR PARTICLES: Option = Full 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 = On Option = Selected Variables Output Variables List = Absolute Pressure,Courant \ Number,Density,Dynamic Viscosity,Eddy \ Viscosity,Pressure,Velocity,Wall Shear,Velocity u,Velocity w,Velocity \ v,Vorticity X,Vorticity Y,Vorticity Z,Wall Shear X,Wall Shear Y,Wall \ Shear Z,Yplus,Wall Normal Velocity,Total Pressure,Turbulence Eddy \ Dissipation,Turbulence Eddy Frequency,Turbulence Kinetic Energy,Total \ Mesh Displacement X,Total Mesh Displacement Y,Total Mesh Displacement \ Z,Mesh Displacement X,Mesh Displacement Y,Mesh Displacement Z,Mesh \ Velocity X,Mesh Velocity Y,Mesh Velocity Z,Boundary Scale,Boundary \ Distance,Mesh Displacement,Mesh Expansion Factor,Orthogonality \ Angle,Orthogonality Angle Minimum,Orthogonality Factor,Orthogonality \ Factor Minimum OUTPUT FREQUENCY: Option = Every Timestep END END TRANSIENT STATISTICS: Transient Statistics 1 Option = Arithmetic Average Output Variables List = Absolute Pressure,Density,Pressure,Total \ Pressure,Velocity,Velocity Correlation,Vorticity,Yplus,Velocity \ Correlation ww,Vorticity X,Vorticity Y,Vorticity Z,Lighthill Stress \ vw,Lighthill Stress ww,Velocity Correlation uu,Velocity Correlation \ uv,Velocity Correlation uw,Velocity Correlation vv,Velocity \ Correlation vw,Boundary Scale,Dynamic Viscosity,Eddy \ Viscosity,Courant Number,Boundary Distance,Mesh \ Displacement,Orthogonality Factor,Orthogonality Angle \ Minimum,Orthogonality Factor Minimum,Orthogonality Angle,Total Mesh \ Displacement,Total Centroid Displacement,Turbulence Eddy \ Dissipation,Turbulence Eddy Frequency,Turbulence Kinetic Energy,Wall \ Shear END END SOLVER CONTROL: Turbulence Numerics = High Resolution ADVECTION SCHEME: Option = Upwind END CONVERGENCE CONTROL: Maximum Number of Coefficient Loops = 10 Minimum Number of Coefficient Loops = 1 Timescale Control = Coefficient Loops END CONVERGENCE CRITERIA: Residual Target = 0.000001 Residual Type = RMS END EQUATION CLASS: continuity ADVECTION SCHEME: Option = Upwind END END EQUATION CLASS: ke ADVECTION SCHEME: Option = High Resolution END END EQUATION CLASS: momentum ADVECTION SCHEME: Option = Upwind END END EQUATION CLASS: tef ADVECTION SCHEME: Option = High Resolution END END INTERRUPT CONTROL: INTERRUPT CONDITION: Interrupt Condition 1 Logical Expression = remeshingcond Option = Logical Expression END END INTERSECTION CONTROL: Option = Direct Permit No Intersection = On END TRANSIENT SCHEME: Option = First Order Backward Euler END END EXPERT PARAMETERS: degeneracy check tolerance = 1.e-2 tbulk for htc = 298 topology estimate factor = 1.8 vector parallel tolerance = 15 END END COMMAND FILE: Version = 15.0 END |
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April 30, 2014, 00:50 |
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#12 |
Super Moderator
Glenn Horrocks
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Location: Sydney, Australia
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You have a velocity specified inlet with an incompressible fluid, and you have talked about an interface opening and shutting. If fluid is forced to flow in the inlet and it is not connected to the outlet and has nowhere else to go then you will crash with an overflow error.
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April 30, 2014, 10:55 |
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#13 |
Senior Member
ali
Join Date: Oct 2009
Posts: 318
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Glenn,
Thanks but what is your suggestion exactly? I mean how else I am supposed to define the problem? specify pressure at the inlet and mass flow at the outlet? why it does not work in this way? |
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April 30, 2014, 11:01 |
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#14 |
Senior Member
Edmund Singer P.E.
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Location: Minneapolis, MN
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When there is no outlet, you are trying to compress the air. Since you are using incompressible air for the fluid, this wont work.
Either switch to air ideal gas (and you will have to deal with the internal shocks), or put an outlet somewhere in your model. |
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April 30, 2014, 11:05 |
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#15 |
Senior Member
ali
Join Date: Oct 2009
Posts: 318
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there is an outlet at the end of second domain. the flow is coming in from the inlet and is supposed to go through the interface and enter the second one and then exit from the outlet in the second domain. Will it work?
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April 30, 2014, 11:09 |
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#16 |
Senior Member
Edmund Singer P.E.
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From your posts, it seemed that for some period of time, your interfaces are not connect. I assume they start off not connected and slide together to connect, thus allowing flow.
During the time they are not connected, you have the situation I described above, with the inlet not seeing any outlet and you are trying to compress the air. So, no, the way you have it set up now will not work. |
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April 30, 2014, 11:55 |
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#17 |
Senior Member
ali
Join Date: Oct 2009
Posts: 318
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Thanks for the info
you can see the both domains in this picture. The left (tiny) one is supposed to move and the other one is supposed to be stationary. The interfaces are initially 100 % overlapping but after time the overlapping part reduces. Inlet is "velocity inlet" and "pressure" at the outlet is specified. at the very end of the simulation the areas are still overlapping(maybe about 10%) but the fact is the periodic boundary conditions specified on both domains for top and bottom surfaces and also having TRS interface should prevent that problem that you are saying. Isn't it? |
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April 30, 2014, 11:59 |
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#18 |
Senior Member
Edmund Singer P.E.
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OK this is a bit different than I described.
When are you getting your error? First iteration? |
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April 30, 2014, 12:05 |
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#19 |
Senior Member
ali
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No, it happens after a while. Like maybe after 15 minutes
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April 30, 2014, 12:16 |
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#20 |
Senior Member
ali
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after 50th timestep
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