**** Entered By: akpaul @ 05/02/2005 05:18 AM ****
Q. I created an expression, areaInt(Velocity*1000 [kg m^-3])@Outlet in CFX-Post. The Value of this expression does not update when I load the intermediate timesteps of a transient solution and click 'Apply' on the expression evaluator form.
A. This is known defect (#33583) in CFX-Post (v 5.7.1 , SP1). Until the error is fixed, you can use the following w |
workaround:<br><br>1- Create an expression, myExp1 = Velocity*1000 [kg m^-3])<br>2- Create a user variable ,myVar1 = myExp1<br>3- Create a new expression myExp2 =... |
Q. A structural analysis in workbench runs successfully to completion, but the reaction forces reported in the details window are greyed out and blank. Why?
A. This was a code defect (#30635) at 9.0. The problem is that the user is switching from sequence to static and internally the sequence number is > 1 which then causes the reaction lookups to fail for the static. It has been corrected for 10.0. |
Q. A structural analysis in workbench runs successfully to completion, but the reaction forces reported in the details window are greyed out and blank. Why?<br><br>A. This was a code... |
Q. In an agdb model, a feature is extruded to a cylinder. On this cylinder I can not apply a bearing load in Simulation. Why not?
A. This was a code defect in 9.0 (#31123) that has been corrected at 10.0. It was related to the fact that shell bodies existed in the model. |
Q. In an agdb model, a feature is extruded to a cylinder. On this cylinder I can not apply a bearing load in Simulation. Why not?<br><br>A. This was a code defect in 9.0 (#31123)... |
When using Workbench Asynchronous Solution / Remote Solve, Is it possible to save the .fadb results file and manually read them on the local PC. |
By default, the Remote solve transfers the files back to the PC, then deletes the solver files and directory.<br><br>How to Save Unix Files and manually read results on local... |
I requested a 'm of 3000, yet the run did not terminate due to insufficient memory on a 32-bit PC. Why doesn't ANSYS report insufficient memory and terminate for 'm 3000? What memory allocation is actually used in this case? |
On 32-bit systems the largest -m value that is allowed is 2000. Above that, you are overflowing the integer value used to store the length of the workspace memory. When the integer overflows it... |
Q. Is there an undocumented way to parameterize the calculated linearized principle stress, stress intensity and equivalent stress generated from PLSECT? *GET documentation lists only component stresses.
A. Yes. As with all undocumented features, check results carefully:
Following the "PRSECT,-1" to PRINT LINEARIZED STRESSES:
for SEQV, use *get,,section,,,S,EQV
for S1, use *get,,section,,,S,1
for S2, use *get,,section,,,S,2
for S3, use *get,,section,,,S,3
for SINT, use *get,,section,,,SI |
Q. Is there an undocumented way to parameterize the calculated linearized principle stress, stress intensity and equivalent stress generated from PLSECT? *GET documentation lists only component... |
Q: I am trying to run the CFX-5.7.1 solver in parallel on an HP itanium cluster. The machines in the cluster have HP-UX 11.23 installed. The run fails and the following messgaes appear at the end of the CFX-5.7.1 solver output file:
+--------------------------------------------------------------------+
| An error has occurred in cfx5solve: |
| |
| echo conf | "/prg/HP_11i/CFX/Shared/pvm3.4.4_11-1/lib/pvm" |
| "/data/New Folder/project1_v3_007.dir/PVMhosts" exited with return |
| code 1. |
+--------------------------------------------------------------------+
+--------------------------------------------------------------------+
| An error has occurred in cfx5solve: |
| |
| Cannot get current PVM configuration: error calling PVM or unknown |
| table format: |
+--------------------------------------------------------------------+
+--------------------------------------------------------------------+
| An error hasoccurred in cfx5solve: |
| |
| echo add ardhps17 | "/prg/HP_11i/CFX/Shared/pvm3.4.4_11-1/lib/pvm" |
| "/data/New Folder/project1_v3_007.dir/PVMhosts" exited with return |
| code 1. |
+--------------------------------------------------------------------+
+--------------------------------------------------------------------+
| An error has occurred in cfx5solve: |
| |
| Unable to find host table in output from PVM daemon: |
| |
Q: I am trying to run the CFX-5.7.1 solver in parallel on an HP itanium cluster. The machines in the cluster have HP-UX 11.23 installed. The run fails and the following messgaes appear at the end... |
Q. When a user makes any revision to a post processing command object in the solution folder, Simulation 9.0 reruns the entire solution. Since post processing doesn't change the DOF solution, a full solve is not required. Is this a bug or limitation.
A. This is a current limitation in 9.0 related to the fact that Simulation is not using the ANSYS rst file. In the current XML approach, Simulation must resolve to retrieve /POST1 and /POST26 results that are requested by way of APDL in command objects. This might be addressed in Release 11.0 when Simulation starts using the ANSYS rst file as opposed to importing XML results. |
Q. When a user makes any revision to a post processing command object in the solution folder, Simulation 9.0 reruns the entire solution. Since post processing doesn't change the DOF... |
How can I start a solver run from the cfx5solve command line and specify:
- Local / Distributed parallel runs?
- PVM / MPI parallel mode? |
<br><br>LOCAL PARALLEL: For a local parallel run the -par-local option is required to specify a local parallel run. In addition, the -part option is required to specify the number... |
What location does ANSYS use to determine the pressure load defined
by a table array? Does it use the node location or the integration point
location? |
As shown in the ANSYS 9.0 example below, the nodal location is used by<br> the code to determine the element pressure load. The Gauss points are<br> clearly in the locations... |
I recently had a temporary ANSYS license file from you for one of my client machines while our usual license server was out of action. Now the usual license server is up and running again and I want to switch the client machine which has been acting as a temporary license server back to being a client machine using the ANSYS licensing on the usual license server. How do I do this? |
You should do the following:<br><br>If the client machine which has been acting as a temporary license server is a UNIX / Linux platform:<br><br>1) Start the ANSYS License... |
When I try to Insert a Comment object into any level of the Workbench Simulation tree (Model, Environment, Solution), I get a Script Error similar to the following:
Script Error
Line: 22367
Char: 6
Error: 'DOM.body" is null or not an object
Code: 800a138f
Source: Microsoft JScript runtime error
Script: commentObj.Text = dhtmlEdit.DOM.body.innerHTML; |
The DHTML edit control is not registered on the machine.<br> The control is C:Program FilesCommon FilesMicrosoft SharedTrieditdhtmled.ocx<br> GUID is... |
When will ANSYS Workbench support Autodesk Inventor 10 ? |
Preliminary testing and feedback from customers indicate that Autodesk Inventor 10 works well with Ansys Workbench 9.0.<br><br> Official testing and support for Autodesk Inventor 10... |
Workbench Graphics Performance (Pan, Zoom, Rotate) is slow with an nVidia Quadro FX graphics board. |
This issue has been observed on the nVidia Quadro FX 4400 graphics board. However, it may be applicable to all graphics cards with the Quadro FX chipset .<br> Also, the system in which... |
**** Entered By: akpaul @ 05/12/2005 10:20 AM ****
Q. I want to specify an entrance region that has laminar flow, which flows into a fully turbulent region?
A. This can be done using the 'Turbulence Transition Model' feature. (Additional licenses may be required). Users can specify laminar and turbulent regions by using the 'Zero Equation' (prescribed intermittency) option of the 'Transition' model. The intermittency can be prescribed as a function of x, y, z coordinates using CEL expressions or a USER FUNCTION. When intermittency = 0, the flow is laminar and when intermittency = 1, flow is fully turbulent.
Example below shows the CCL options for setting a prescribed intermittency transition model. The intermittency is defined by a user function, which returns 0 (laminar) or 1 (turbulent) based on geometric location. (NOTE: At 5.7 and 5.7.1 releases the transition model options can only be setup by editing CCL in PRE or using a text editor. There are no GUI buttons to turn ON transition model)
FLUIDS MODELS:
TURBULENCE MODEL:
Option = SST
TRANSITIONAL TURBULENCE:
Option = Specified Intermittency
Intermittency = TRANSITION TRIP(x,y,z)
END
END
END
CEL:
FUNCTION: TRANSITION TRIP
Option = User Function
Argument List = [m],[m],[m]
Result Units = []
END # FUNCTION
END
USER ROUTINE DEFINITIONS:
USER ROUTINE: TRANSITION TRIP
Option = User CEL Function
Calling Name = transition_trip
Library Name = transitiontrip
Library Path = /myhome/UserSource/
END
END
Full details and options for the transition model is available in the attached PDF file. |
**** Entered By: akpaul @ 05/12/2005 10:20 AM ****<br>Q. I want to specify an entrance region that has laminar flow, which flows into a fully turbulent region?<br><br>A. This can... |
Are there any ANSYS LS-DYNA full restart examples showing a change in
displacement loading via EDLOAD? I can get force loading to change,
but not displacement loading. |
Please see the ANSYS LS-DYNA 9.0 model below. Be careful not to make<br> any abrupt changes to displacements, as infinite accelerations will result.<br><br>! = = = = = = =... |
Calculation of torque from friction force between 2 contact surfaces
--------------------------------------------------------------
QUESTION:
Do you have an example illustrating a procedure for simulating a swaging operation? I want to simulate the operation itself and then perform a "virtual test" to see if the friction in the swage joint can support a certain amount of twist imposed on the end of the shaft.
ANSWER:
See the attachment to this solution. An axisymmetric part with hole slightly larger than the shaft is swaged onto the shaft. The pressure causing the swaging is removed, and the tip of the shaft is twisted one full degree. |
Calculation of torque from friction force between 2 contact surfaces<br>--------------------------------------------------------------<br><br><br>QUESTION:<br>Do you... |
Q. How do I import a mesh from Ansys into CFX-Pre so that I can use it for CFD? I need to have boundary locations defined too.
A. You can import meshes created in either Workbench Simulation or Classic Ansys.
Workbench Simulation:
Having brought your geometry into Simulation, you should set up any mesh controls you think necessary (by right clicking on 'Mesh' and using Insert) and then preview the mesh. Next you need to set up individual surface loadings on each surface you intend to use for a CFD boundary condition. It doesnt really matter which loading you use, but perhaps its easier to set up a pressure loading using a right click on Environment, and Insert. The name of the loading is irrelevant also, but you should enter a non-zero load. Next, click on the Solution part of the tree, then right click and insert a Total Deformation section, and then finally select Tools/Write Ansys Input File. Write out the file (its a text file) with a .cdb extension.
Classic Ansys:
Create your mesh from the geometry in any manner you wish. However, you must use an appropriate element type: a lot of types are supported but some only with the correct keyoptions. Its best to try to use a 3D structural element like Solid45, or perhaps Fluid142. Once you have your mesh, you need to define nodal component groups to represent your boundary locations. The quickest way to do this is to type 'asel,s,p' and then pick a surface(s) for the location. When done, type 'nsla,s,1' to select all nodes associated with that surface. Then type 'cm,locname,node' changing the locname as appropriate, to create the group. Repeat for all locations, and then finish by typing 'allsel'. Export the file by typing 'cdwrite,db,myfilename,cdb' chaning the filename as required.
When importing the mesh into CFX-Pre, select the ANSYS filter and the .cdb file you wrote out. You may get a message about midside nodes being ignored but that is perfectly normal especially if the file has come from Wor |
Q. How do I import a mesh from Ansys into CFX-Pre so that I can use it for CFD? I need to have boundary locations defined too.<br><br>A. You can import meshes created in either... |
Q. How to I implicitly model an axial fan in CFX, using a fan curve?
A. You can implicitly model a fan in CFX without actually having to include any of its geometry by using a momentum source instead. To do this for an axial fan, you must mesh your geometry such that you have a cylindrical 3D mesh region (perhaps a frozen solid in CFX-Mesh) that represents the fan within the flow domain as a whole. This is so that within CFX-Pre you can create a subdomain using that 3D region, and create the equation sources there. At this point, you should create and name the subdomain but dont set up any sources. You may also want to create a thin wall on the curved surface of the cylindrical region to represent any ducting on the fan.
Next, you must create a Function, using the Interpolation and One Dimensional options. This will represent your fan curve and you must enter the data points in pairs from your curve taking care that the argument and result units are correct. Usually the argument is a flow rate and the result a pressure. Try to enter a point at each extreme of the curve, but make sure you set the extend max/min to off.
Next you should set up two simple expressions equal to the radius and axial length of the cylindrical 'fan' region. Next, create anotherexpression representing the flow rate through the fan region. This will look something like:
FanLength = 0.2 [m]
Fanrad = 0.3 [m]
FanQ = max(1E-6 [m^3 s^-1], volumeAve(Velocity)@fansub*3.14159*fanrad^2)
Here, 'fansub' is assumed to be the name given to the subdomain, and 'fanrad' is the name of the expression defining the radius of the cylindrical region.
Next, edit the fan subdomain and check the Sources box on the Source tab. Select Momentum Sources and a General Momentum Source. Hopefully, the axis of your fan is aligned with one of the global coordinate axes and so you need enter a non-zero value in one component only. The component expression should read (eg. Z direction):
Momentum So |
Q. How to I implicitly model an axial fan in CFX, using a fan curve?<br><br>A. You can implicitly model a fan in CFX without actually having to include any of its geometry by using a... |
When I try to open a geometry file in DesignModeler, I get the following script error:
Script Error
Line: 16272
Char: 2
Error: 'ColumnHeaders' is null or not an object
Code: 800a138f
Source: Microsoft JScript runtime error
Script: ctrl.ColumnHeaders.Clear();
The Model / Construction tree is missing from the left side of the window. |
This is a known bug that occurs when the Panes are resized to the edge of the screen.<br><br>To Reset the Panes:<br><br> Start > Run > Regedit.exe<br> ... |
Although turbo initialization in CFX-Post looks fine, in the blade-to-blade views there is the location of phi = 0 visible in the rotor domain (e.g. 2 parts of span=50% surface displayed). How can the view be improved? |
In ANSYS CFX 10 the Theta=0 position can be adjusted via a slider in the Blade-to-Blade plot editor.<br> In ANSYS CFX-5.7.1 there is an environment variable which can be set to define the... |
QUESTION:
I need to extract the reaction force FX of some nodes fixed using D,node#,UX in an LS-DYNA model. I tried RFORCE command in POST26 but the generated variable was shown to be "invalid". How can I obtain an xy plot of the reaction force vesus time in POST26?
ANSWER:
Before solving, you need:
EDOUT,RCFORC
Then, in POST26, do, for example, the following:
FILE,,HIS
EDREAD,2,SPCFORC,25
This will read node 25 x, y, and z reaction forces into POST26 variables 2, 3, and 4, respectively. Plot the reaction forces vesus time using PLVAR,2,3,4. |
QUESTION:<br>I need to extract the reaction force FX of some nodes fixed using D,node#,UX in an LS-DYNA model. I tried RFORCE command in POST26 but the generated variable was shown to be... |
Q) When importing my Pro/e model into ANSYS Design Modeler v 9.0, I get the error message "No Valid Bodies"
A) Import the model into Design Modeler with the following options in the 'Details View':
Process - Solids Only
Simplify Geom - No
Heal Bodies - No
Clean Bodies - No
Mixed Import Resolution - Solid
The Mixed Import Resolution is a key item for ProE since it supports parts that contain both solids & shells (surface bodies), which is illegal in Design Modeler. |
Q) When importing my Pro/e model into ANSYS Design Modeler v 9.0, I get the error message "No Valid Bodies"<br><br>A) Import the model into Design Modeler with the... |
Our customer wants to know, which entry in the Harwell-Boeing output of the stiffness matrix correlates to which degree of freedom in the model? |
The following information concerns the interpretation of the Harwell-Boeing output generated from an ANSYS run. This information is current for release 9.0.<br><br>Included in this... |
Do you have an example of circuit coupling (CIRCU124) used in combination with electric field elements (SOLID231) used to model fields and current in biological tissue? |
<br>The attached zip file contains an example.<br><br>A simplified 3D model of an electrode embedded in a cube of ¿tissue¿ having spatially varying orthotropic... |