User receives the following error when running ANSYS 8.1/9.0 on Sun Solaris 10:
Error in startup script: couldn't load file
"/ansys_inc/v81/commonfiles/launcher/lib/ansinfo/../usIII/libansinfo.so"
: ld.so.1: /apps/ansys/v81/commonfiles/Tcl/bin/usIII/wish: fatal:
relocation error: file /ansys_inc/v81/ansys/syslib/usIII/libucb.so.1:
symbol _siguhandler: referenced symbol not found
while executing
"load
/ansys_inc/v81/commonfiles/launcher/lib/ansinfo/../usIII/libansinfo.so
ansinfo"
("package ifneeded" script)
invoked from within
"package require ansinfo"
(file "/ansys_inc/v81/commonfiles/launcher/LauncherMain.itcl" line 44)
What would cause this error?
Is there a fix? |
The syslib/usIII/libucb.so.1 file that ANSYS delivers with ANSYS 8.1/9.0 doesn't work well with Solaris 10.<br>This file contains a reference to _siguhandler (as shown below) that is... |
Why is SuSE linux used on the Opteron platform and Redhat linux used on the EM64T platform? |
We use SuSE Enterprise on Opteron for Ansys90SP1 and Ansys100.<br>We use RH AS 3.0 on Intel EM64T for Ansys90SP1 and Ansys100.<br><br>Reason: AMD & PGI Compilers recommend... |
Q. User is attempting to apply a rotational displacement about a user defined cylindrical coordinate system in Workbench.
Details window correctly reports the cylindrical coordinate system and the Y displacement applied in units of degrees.
Instead of rotating the geometry as expected, Simulation applies a linear displacement in the Y Cartesian system.
How do you apply rotational displacements in Workbench?
A. This is a beta feature in Workbench 9.0 that is not working correctly. The option to use a cylindrical coordinate system as a basis for applying an angular displacement will be blocked at 10.0.
The remote displacements feature is recommended as an alternate and is also available at 9.0. |
Q. User is attempting to apply a rotational displacement about a user defined cylindrical coordinate system in Workbench.<br>Details window correctly reports the cylindrical coordinate... |
My results do not appear to be correct for my ANSYS 9.0 PLANE182 model in
which I have local cylindrical coordinate systems defined. Is this a known bug? |
Yes, Defect 31168 was filed in corrected in the production version of ANSYS 10.0.<br> This is a Class 3 Error, which is described below. A final Class 3 Error number has<br> ... |
QUESTION:
When trying to do an FSI (FLOTRAN-structure) analysis, the following message consistently appears:
Error - "inverse subroutine was supplied with a singular matrix"
I should note too that I have come across this problem a while back. No matter what I did I kept getting the same error. What I eventually ended up doing was not having the fluid and structural volumes/meshes touch each other except for the area of interest. If I recall correctly, that error arises when there's something wrong with the fsi flagged surfaces. I tried flagging a small portion of the model to see if this leads anywhere.
ANSWER:
The attached input files were created to test the conditions described below:
1) mdl04a.inp: ALL HEX MESH, PRES=0 BOUNDARY DOES NOT TOUCH FSIN (RUNS FINE)
2) mdl04b.inp: CFD WEDGE ELEMS, PRES=0 BOUNDARY DOES NOT TOUCH FSIN (RUNS FINE)
3) mdl04c.inp: CFD WEDGE ELEMS, PRES=0 BOUNDARY TOUCHES FSIN (APPLICATION ERROR)
4) mdl04d.inp: ALL HEX MESH, PRES=0 BOUNDARY TOUCHES FSIN (RUNS FINE)
5) mdl04e.inp: ALL HEX MESH (UNEQUAL SIZE), PRES=0 BOUNDARY TOUCHES FSIN (RUNS FINE)
What this means for you is you should either:
a) ensure pure hex mesh - it'll run whether or not the PRES=0 boundary touches the FSIN, or,
b) extend wedge mesh so that it extends beyond and fully encloses the FSIN surfaces |
QUESTION:<br><br>When trying to do an FSI (FLOTRAN-structure) analysis, the following message consistently appears:<br><br>Error - "inverse subroutine was supplied... |
How to define volume particle injection locations with User Fortran and Zero Slip Velocity? |
From version Ansys CFX 10 on, the following CCL can be applied for volume particle injection. Note that the "Zero Slip Velocity" Option is not available in the... |
Q) I am having a memory problem using a GGI interface where two solids are meeting.
I have imported the solids in 1 part directly from a CAD source into CFX-Mesh, but it comes in as seperate parts (bodies)
A) To get the solids to `see' each other without them being in the same part, you will need to specify them as periodic pairs.
i.e. each pair of faces that share the same surface you need to make them a periodic pair. Make sure you have the transformation as 0 0 0
This should give 1-1 interfaces in Pre and therefore the memory problem should disappear. |
Q) I am having a memory problem using a GGI interface where two solids are meeting.<br>I have imported the solids in 1 part directly from a CAD source into CFX-Mesh, but it comes in as... |
Q) I have a long transient run that has monitoring point information. when the simulation finishes, the .def file and the mon file are not joined together. How can I join them together or extract the monitoring point information?
A) CFXDfile will enable you to extract the data from the mon file. There should be instructions on how to do so in the manual.
You can combine these files in CFX10, the next release (due for release in a few weeks), but not, I'm afraid in cfx5.7.1. |
Q) I have a long transient run that has monitoring point information. when the simulation finishes, the .def file and the mon file are not joined together. How can I join them together or extract... |
Q) I have a model of a vertical section through a probe design (see attached parasolid file for geometry). I have run a solution in CFX-5 (heat transfer only, no flow) and I seem to be having problems at some of the interfaces - some cells at the interfaces between the different regions show spurious temperatures lower than any of the temperatures set in the boundary conditions (see attached .png picture file for locations). Is this likely to be due to a problem with the mesh?
A) You are right, there is a low temperature which can be seen in Post and Fieldview.
If you go into Pre and the domain interface (which is created automatically when you have a 1-1 interface) and change the Connection Type to GGi this will then be fine.
For a solid-solid interface where the conductivity is very different for the two solids, this is done automatically. Your case is a solid and a fluid, but the fluid has no advection, so it is essentially acting as a solid with a low conductivity and is therefore causing the problem.
In summary, it should be fine to have automatic as the interface except in cases such as yours. |
Q) I have a model of a vertical section through a probe design (see attached parasolid file for geometry). I have run a solution in CFX-5 (heat transfer only, no flow) and I seem to be having... |
Q) Do you recommend a VRML viewer for the vrml files from Post in CFX-5.7.1? The one recommended in the help does not seem to work. Is there a problem with the VRML output from Post?
A) Yes there seems to be a problem with VRML output on 5.7.1, but it seems to be fixed in CFX 10.0.
Unfortunately the only way to make it work is to tweak the VRML file manually. To get all of the objects to display correctly, you will have to do the following:
1) Open the .wrl file in a text editor.
2) Search for the word: Viewpoint
3) Just below Viewpoint, there is a parameter called 'fieldOfView'. It will probably have some value greater than 5. Replace this value with 0.4. I.e. resulting line: "fieldOfView 0.4" (no quotes)
4) Three lines below fieldOfView is a parameter called 'position'. It will have a value of "0 0 -5", change it to "0 0 5" (no quotation marks) I.e. negate the 5.
5) Save the .wrl file and reload in your VRML browser.
These steps should have made your 3D objects visible.
If you want to make your 2D objects and the CFX toggle buttons visible, follow the following steps:
To make the CFX toggle buttons visible:
1) Open the .wrl file in a text editor.
2) Search for the word: myLineButton
3) Just below this line, there is a parameter called 'translation'. You must negate the Z coordinate of this parameter( i.e. the last number). It will have a value of 0.25, and you must change it to -0.25.
4) Repeat steps 2 & 3, searching for myFaceButton and myBackdropButton.
To make any 2D objects that you defined in post visible (e.g. Legends, Logo, Text Objects, etc):
1) Open the .wrl file in a text editor.
2) Search for: myStaticOverlay This is actually just a part of the word that will exist in the file. You will see object definitions such as: myStaticOverlay0Transform and myStaticOverlay1Transform.
3) Search for: Transform This should exist around 7 lines below the line with myStaticOverlay.
4) Just below the Transform line, you will find th |
Q) Do you recommend a VRML viewer for the vrml files from Post in CFX-5.7.1? The one recommended in the help does not seem to work. Is there a problem with the VRML output from... |
I have created a geometry and a mesh with DesignModeler in Workbench 9.0.
I want to make a copy of the geometry and the underlying mesh (with mesh-controls, 2D-regions etc).
Please can you show me how to do this? |
In the following workaround, I will assume that you want to copy<br>a) a geometry file (agdb )<br>b) CFX Mesh files (cmdb and cmdat )<br>and put all these files into a new... |
Calulated net conductor joule heat not increasing with frequency as expected when using SOLID117 model
--------------------------------------------------------------
QUESTION:
A SOLID117 model (attached) was built for simulating the joule heating induced by both eddy current and electrical heat dissipation (I^2*R). The unit used in the model is umksv. It has been found that the joule heating is extremely insensitive to the applied AC frequency.
The joule heating calculated increases less than 1% when increasing the frequency from 250MHz to 400MHz. However, the measured temperature rise (over ambient) increases 50% when the frequency changes from 250MHz to 400MHz. I don't understand why the difference b/w measurement and modeling is so large. Can you please explain this behavior?
ANSWER:
Before a SOLID117 model will give accurate results for this type of analysis, the following conditions must be satisfied:
1) At release 9.0 and earlier, the conductor mesh must be hexahedral. Tetrahedral meshes will not give correct results, regardless of mesh size.
2) The current must be modeled in such a way that it is solenoidal (current cannot "appear from nowhere' and enter one end, nor can it "disappear into nowhere" and the other conductor end). This is not physically possible, and if conductor ends begin and terminate in the middle of an "air" mesh using SOLID117, calculated results will be completely wrong and there will be no warning to the user that the conductors have not been modeled correctly.
Satisfying the solenoidal condition can be accomplished in 2 ways:
a) It can be implied by symmetry. For example, a 1/4 symmetry model (90 degree sector) of a cylindrical air coil will correctly model the current as being solenoidal.
b) The conductor leads can be routed to and cut perpindicularly by a planar flux parallel model boundary. In this case, the conductor ends are modeled in the usual way: couple VOLT on one end and apply the total current |
Calulated net conductor joule heat not increasing with frequency as expected when using SOLID117... |
How to obtain mass flow rates of single components or single phases in simulations involving variable composition mixtures or multi-phase flows, using CEL expressions during the solver run: |
<br><br>1) Mass flow rate of a single component in a variable composition mixture:<br><br> Mass Flow CO2 = massFlowInt(CO2.Mass Fraction)@out<br><br> The... |
How does CFX-5 calculate the fluid specific general momentum source in Eulerian multiphase flows? |
The fluid specific momentum sources in multiphase flows are defined in CFX-Pre or CCL as follows:<br><br>FLOW:<br> DOMAIN: Domain 1<br> SUBDOMAIN: Subdomain... |
Q) What size mesh should we use for LES and DES calculations?
A) In general with LES you want to put the cut off point (i.e. cell size) of the small eddies to be in the inertial sub-region.
This is the linear region (with a slope of -5/3) of the plot of logE v frequency.
For DES, for the LES regions you should apply the above advice.
Regarding aspect ratios. f you have large aspects rations you are introducing anisotropy into the turbulent so effectively you might be only getting the benefit of the largest of the cell edges. Also, you can get into stability issues when you have too large (> 5 or 10) aspect ratios.
With respect to cell size expansion you will start getting into trouble if this is larger than 1.2. It can be better for expansion to use a tet grid in terms of stability, but there be issues of diffusion (which will aid stability!).
For more information I would have a look at some of the literature, for example Piamelli.
There are also some paper we have on SAS modelling which looks at some of these issues. Please contact the Helpdesk at ANSYS Europe Ltd. |
Q) What size mesh should we use for LES and DES calculations?<br><br><br>A) In general with LES you want to put the cut off point (i.e. cell size) of the small eddies to be in... |
Q) How can I calculate moments in CFX-Post, but not around the global coordinate system?
A) Create a new coordinate system in CFX-Post. After this, go to Tools/Calculator and click on Axis and you will have the choice of the global coordinate system and any coordinate systems you have created. |
Q) How can I calculate moments in CFX-Post, but not around the global coordinate system?<br><br>A) Create a new coordinate system in CFX-Post. After this, go to Tools/Calculator and... |
I am trying to create a 3D Curve using points "From Coordinate File",
but I am getting an error message about violating the workspace:
Error: Points in Coordinates File are outside valid range
It seems that I cannot create any geometry past 500 meters. Why? |
This is a known limitation related to the Parasolid geometry engine.<br> Parasolid geometry must reside within a 1.0 km^3 box that is centered<br> about the origin. ... |
How can I stop getting a wall at 360 degrees when importing a CFX-4 cylindrical 360 degrees mesh into CFX-5.7.1 Pre? |
Make sure that ,when you import your CFX-4 mesh, you tick the option 'Duplicate Node Checking' on the 'Advanced options' tab.
|
**** Entered By: akpaul @ 07/14/2005 09:10 AM ****
Q. I notice that the CFX Solver does not include the turbulence residual values in the convergence check. How can I force the solver to also look at the turbulence equation residuals before stopping the run with an "ALL RESIDUALS ARE BELOW TARGET" message?
A. By default the turbulence equation residuals are not included in the convergence checks. You can force the solver to do so by adding the following expert parameter:
EXPERT PARAMETERS:
target residual tke eps = <value>
END |
**** Entered By: akpaul @ 07/14/2005 09:10 AM ****<br>Q. I notice that the CFX Solver does not include the turbulence residual values in the convergence check. How can I force the solver to... |
What is the reason for a negative enthalpy flux at an inflow condition? |
The enthalpy flux is depending on the reference enthalpy and the reference temperature.<br><br>Example: For a zero reference enthalpy at 25 C, the enthalpy becomes negative for an... |
How are total principal and equivalent strains calculated? Are these calculated based on total strain components or by summing elastic, plastic, creep (and thermal) principal and equivalent strains directly? |
Total equivalent strain is calculated by summing equivalent elastic, plastic, creep (and thermal) equivalent strains, per Section 19.12.5 of the ANSYS 9.0 Theory Reference. Note that the... |
I would appreciate some input on the problems I have been experiencing
with the SST model. I have generally been using the KE model but am
trying to improve on the heat transfer predictions by using a K-omega
model near the wall (i.e. SST). Unfortunately I have a separation point
for which the SST model cannot calculate a converged solution:
Model (see fig3 of attachment):
- Rotor-Stator gas turbine cooling chamber (1/60th segment modelled)
- Axisymmetric slot inlet in the stator at low radius
- Discrete hole outlet in rotor at high radius (represents entrance to
blade cooling passage)
- All walls adiabatic except rotor
Mesh:
- Tetrahedral mesh with inflated boundary regions (created in CAD2MESH)
- Y+ is generally 20ish to make use of wall functions
- The refined mesh in the area of interest has Y+ < 1
KE:
- The K-Epsilon model has given good results for fluid dynamics but
over-estimates heat transfer from the rotor (as expected)
Problem:
- Below the inlet are two secondary recirculating flows (fig 1 & 2 of
attachment). Between these regions, at the point highlighted the total
velocity of the flow relative to the surface is zero, i.ethe is flow
separating from the surface and the shear stress goes to zero. The SST
model will not converge(Momentum RMS = 5x10^4), and the maximum
residuals for all properties occur at this point.
Attempted:
- Using the KE results as an initial value file
- Refining the grid in the area
- "tef numerics option" = 1
Do you have any suggestions how I can get results using this model? |
<br>The problem you experience could very well be related to the fact that the SST model is a much more accurate model than the KE model. I assume that the purpose of changing to the SST... |
I have recently installed ICEM CFD 5.1 (no service packs) onto my laptop (Windows XP Pro) with Unigraphics NX3 installed. I have a trial ICEM CFD license (ANSYS daemon) for the laptop which includes the Direct Interface for Unigraphics license key aipiug. When opening Unigraphics NX3 I get the ICEM CFD Grid Generation option under the Applications menu but when I select it I get the message:
No ICEM UG Direct Interface licenses available.
Either all licenses are in use or there is a license configuration problem.
If you need a license file, please consult the ICEM CFD documentation
for information on obtaining one. If you already have a license file
try using the Probe License feature under the ICEM CFD menu or call ICEM CFD
technical support for help in troubleshooting your license configuration.
The ICEM CFD menu still becomes available at this point.
ICEM CFD as a standalone application starts fine, and the ANSYS license manager is up and running. I have set the ICEM_ACN and ICEM_LICENSE_FILE environment variables myself but this has not resolved the problem. Any ideas as to how to get this working? |
Unigraphics version NX3 is not supported by ICEM CFD 5.1 though it will be by ICEM CFD 10.0; version 5.1 supports version 18.0, NX and NX2 andthe interface files needed for these versions are... |
Q) How do you make a copy of a sketch in DesignModeler, and then Paste that sketch into a new sketch?
A) With the original sketch open, click on the modify tab. Select the part (or all) of the sketch you would like to copy, click on the copy button. Right click in the viewport and select "Use Origin as Paste Handle, this sets the origin as the reference point. Create a new sketch and once again click on modify. Click on the Paste option, you can now choose if you would like to rotate the sketch and or scale it. If neither simply right click and choose to Paste at plane handle, this will paste it back in the same spot of the sketch as it was copied. Right click again and paste additional sketches or choose end to stop pasting the sketch. In Ansys 10, you will no need to goto the Modify tab, as both copy and paste will be available via the RMB menu. |
Q) How do you make a copy of a sketch in DesignModeler, and then Paste that sketch into a new sketch?<br><br>A) With the original sketch open, click on the modify tab. Select the part... |
**** Entered By: akpaul @ 07/18/2005 03:45 PM ****
Q. How can you preload a structural model prior to doing an FSI analysis with CFX?
Here's the situation: Client wants to twist a structural model which will create stored energy independent of CFX. He then wants to release the structural model and have it swing back to its original state while being damped by a fluid modeled with CFX in a transient analysis. He needs to have the CFX mesh morphed to the shape of the deformed structural model prior to the first step so it is ready to start damping the transient response. Is this possible? He does not want to have to run a long transient initially just to set up the structural preload in his model.
A.
The best way to setup a FSI case with pre-loading using the MFX solver, is to run two simulations as given below:
1)Pre-Load Step: A regular FSI simulation is executed, but no forces are received from CFX. Instead, a force boundary condition is applied in ANSYS. The solid model mesh moves, and deformations are transferred to CFX. Hence you will only define one FSI interface in the Ansys input file - one that sends 'Displacements' to the corresponding boundary condition in CFX.
Note that the CFD domain feels this motion and establishes a flow field. However, You can set an expert parameter in the CFX def file, 'SolveFluid = f' (Solve Turbulence = f' etc..) to stop the solver from computing a solution for the momentum and turbulence equations. In which case, CFX will only solve for the mesh deformation, which will reduce the time and computational effort required. This simulation is run until the desired preload is realized.
2) Fully Coupled FSI/Damping run. - This essentially is a FSI restart. Make sure all the run files from pre-load step are available in the working directory. In the input file add the second FSI interface - the one that transfers forces from CFX to Ansys. Also remove the pre-loading pressure. For CFX the 'Initial Values File' w |
**** Entered By: akpaul @ 07/18/2005 03:45 PM ****<br>Q. How can you preload a structural model prior to doing an FSI analysis with CFX?<br><br>Here's the situation:... |