Q) I am running a case in which I want to have a pre-defined pressure at a certain point of the computational domain. This is accomplished by (manually) justifying the outlet pressure of the domain and keeping everything else constant. I have created a monitoring point at that location:
MONITOR POINT: p monitorinpoint Cartesian Coordinates = -1.05 [m], 0 [m], 0.03 [m] Option = Cartesian Coordinates Output Variables List = Pressure END
After a couple of trials I found an outlet pressure that leads to desired pressure in the monitoring point (following this via the CFX-Solver Manager). Surprisingly, looking at the results in POST and probing a pressure at this point gives a pressure value that is about 10 Pa lower than according to the GUI of Solver Manager. Pressure level in the monitoring point is around 46 500 Pa.
How is it possible that pressure in this particular point is somewhat different in Solver Manager and in POST? This complicates the solution procedure, as in the system slight pressure changes are of major importance. Therefore I should always check the pressure in POST rather than in Solver Manager.
A) This seems to be a difference between the interpolation in the solver and Post. In the Solver Manager Gui the values are calculated using a nearest neighbour (vertex) calculation and in CFX-Post (the more accurate) a tri-linear interpolation. The finer the grid, the smaller the difference between the results should be. |
Q) I am running a case in which I want to have a pre-defined pressure at a<br>certain point of the computational domain. This is accomplished by<br>(manually) justifying the outlet... |
How can you calculate the dot product of two vectors? |
In ANSYS, Release 10.0, you can use *VOPER to calculate the dot product of two vectors. The i,j,k values for each vector are stored in rows of an array. The scalar result is then stored in... |
How can you calculate the cross product of two vectors? |
In ANSYS, Release 10.0, you can use *VOPER to calculate the cross product of two vectors. The i,j,k values for each vector are stored in rows of an array. The i,j,k values of the result vector... |
Every time I run Help in CFX for the first time, I receive the error
readerShowPage: reader failed to start.
When I next try to open it, it is OK. |
This problem is due to a delay in starting the Java virtual machine. When you click on Help the Java virtual machine is started and this can take a few seconds. The connection can time out causing... |
The aienv license does not work after installing service pack 1 for ICEM CFD 10.0. After installing the service pack, the customer gets the following error:
Product: ANSYS ICEM CFD Mesh Editor (feature "aimed")
Checkout failed for the above product. FLEXlm error message:
No such feature exists. (-5,412)
The customer only has licenses for aienv and aisub, has never had a license for aimed. Why is he getting this error with the service pack? |
We were able to reproduce the error here and it will be fixed in a future release.<br>For now, the work-around is to add -ai to the icon target.
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I am trying to use the Cast Iron Material model to simulate different yield strengths in Tension and Compression. My Tensile strength is higher then my compressive strength. The stress-strain curve in /POST26 does not match the curve defined in the material law! It seems that the compression curve is used in the tension case? Is this a bug? |
No. When you defined the tensile strength as higher then the compressive strength, you essentially shifted the composite (Rankine-Von Mises) yield surface (illustrated in Figure 4.10 of Theory... |
What is the limit on number of nodes for university licenses? |
The limit on number of nodes is as follows:<br><br>ANSYS Research license (aunivres) - limit of 512k nodes<br>ANSYS University Advanced (ansysrf) - limit of 128k... |
Will CFX 10.0 take advantage of the /3GB switch for the Windows XP Operating System? |
Yes, CFX 10.0 is linked with the ¿largeaddressaware option, so we should be able to take advantage of the /3GB setting.<br><br>However, the memory can become fragmented by the... |
The CFX 10.0 Solver terminates with messages:
Existing GGIVx array found. Although it does not appear to be compressed, it should be. Stopped in routine FLAG_GGIVX
What should I do? |
Make any domains completely surrounded by other domains which are at least two mesh cells thick
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What version of SAMsuite is needed to track ANSYS 10.0 license usage? |
ANSYS 10. uses FLEXlm v10.1.3.<br> FLEXnet Manager v1.9 can generate reports for the ANSYS 10.0 license manager.<br> SAMreport v3.6 is compatible with the ANSYS 10.0 license... |
The customer can borrow one license for ANSYS 10.0, but is not able to run the product when disconnected from the network. It seems that ANSYS is still trying to connect to the license server instead of using the borrowed license. What could cause this? |
In this case, the ANSLIC_ADMIN Utility was version UP 20050209.<br> Updating it to UP20050718 (Version 10.0) permitted the license borrowing feature to work properly.
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How to solve supersonic Laval nozzle flows efficiently and quickly? |
Use one of the the following solving strategies:<br><br>Strategy 1 (robust), works only for subsonic outlet, i.e. the outlet must be downstream of the shock:<br><br>1)... |
How can cameras be defined in CFX-Post session files? The definition of quaternions used in CFX-Post cameras is not obvious. |
2 possible solutions are:<br><br>1) Use CFX-Post GUI to define the cameras and write the cameras to a state or session file, so that the CCL for the desired cameras<br> can be... |
I would like to make a configuration study with small changes in geometry using DesignModeler and CFX-Mesh. The changes are limited to modifications of lengths/angles so that the number of faces is kept constant and the topology not modified. In order to keep track of all our configurations, we would like to have a consistent file system with one directory for each configuration containing the geometry file and the mesh file (optionally the CFX files). All the files related to configuration 1 are stored in Directory1 (Configuration1.wbdb, Geometry1.agdb, Mesh1.cmdb, Mesh1.cmdat). Directory2 contains the files for configuration 2: Configuration1.wbdb, Geometry2.agdb, Mesh2.cmdb, Mesh2.cmdat.
How can we re-use the mesh settings of configuration 1 for configuration 2 in order to avoid starting from scratch again ? |
If you have a set of mesh controls which you are happy with and want to use it on another geometry/workbench project (i.e. not importing the geometry into the first project) here are some... |
How can the default number of circumferential stage interface bands be changed? |
There is an undocumented expert parameter:<br><br> EXPERT PARAMETER:<br> ggi stage groups max = 40<br> END<br><br>40 is the... |
Q) I'm running a simulation of a recirculation system, i.e. no net in- or outflow, but with a moving wall driving the flow. I have seen in the solver that the pressure is automatically set to zero in one point, but I would like to know if I can specify the location of this point in CFX-Pre?
A) This is set in Solver Control/Advanced Options/Pressure Level Information. Change Automatic to Cartesian co-ordinates. For multiple domains, there is a pressure reference point for each domain. |
Q) I'm running a simulation of a recirculation system, i.e. no net in- or outflow, but with a moving wall driving the flow. I have seen in the solver that the pressure is automatically set... |
Q. I am trying to import a mesh file generated with Gridgen into CFX-Pre at version 5.7 and I get the following error. What can I do about it?
>There was a problem importing the mesh from the requested file. >The importing process reported the following problem: > >Unable to import mesh: Insufficent memory to 3D region. >
A. This is a known problem with CFX 5.7 that was fixed in CFX5.7.1 and subsequent versions. It is necessary to upgrade. |
Q. I am trying to import a mesh file generated with Gridgen into CFX-Pre at version 5.7 and I get the following error. What can I do about it?<br><br>>There was a problem... |
Q. I am plotting a rainbow scaled plot of a variable in Post but am noticing areas of the plane to be gray. This color is not part of the color legend which describes the range of variables. What does this mean?
A.
This occurs when the variable itself is undefined or not valid in this region. A more typical instance of this would be when one tries to plot velocity in a solid region. It isn't defined as zero, it just isn't defined.
If you click on a defined region and in the resulting box change the mode to variable, you will see a bar at the bottom of the dialog box which says "Undef. Color". It is most likely indicates that gray is used for undefined values. |
Q. I am plotting a rainbow scaled plot of a variable in Post but am noticing areas of the plane to be gray. This color is not part of the color legend which describes the range of variables.... |
In some cases mesh deformation can result in negative volumes and hence solver failure. How to avoid this? |
When no Mesh Stiffness parameter is set or a constant stiffness is set, then a linear deformation of the mesh is expected. However, when the element sizes vary to a great extend, then it may... |
Parallel User Fortran (MPI) fails on Windows XP after ANSYS CFX 10 SP1 installation |
Add the following path to the PATH environment variable:<br><br> C:Program FilesAnsys IncCFXCFX-10.0binwinnt<br><br>Adjust the path according to your installation. For... |
I am experiencing problems when importing STEP/IGES into ICEM CFD 10.0. It works fine in ICEM CFD 5.1 |
You need to have the latest Service Pack installed i.e. ICEM CFD 10.0 SP1.<br>You should then be able to "Use Version 5.1 STEP Translator" under the IGES import menu (this... |
When I try to use the help function within CFX10 I get the following error message.
'Help error: Error returned from help viewer StartReader: Reader exec call failed'
Note that I have installed the latest version of Java |
Some of the newer versions of Java seems to create problems with the Registry keys on Windows machines. Therefore it is suggested that you use the version of Java which is provided on the... |
Q) How can I display wall shear stress based on 'time averaged velocity' in CFX 10.0 Post?
A) You will need to set the variable Wall Shear under TRANSIENT STATISTICS.
To do this, change the def file (using the cfx5cmds command) |
Q) How can I display wall shear stress based on 'time averaged velocity' in CFX 10.0 Post?<br><br><br>A) You will need to set the variable Wall Shear under... |
Figure 4.5 "Uniaxial Behavior for Multilinear Kinematic Hardening" in the ANSYS 10.0 Theory Reference shows a default MKIN tangent slope of zero after the fifth (last) MKIN defined point. However, it looks like ANSYS is just extending the last defined slope instead of using a zero tangent slope. Actually, ANSYS should be using a slope that is 1.0e-6 times the Young's modulus, which is essentially zero, but a little more stable than perfectly plastic. Due to the error, the new generation elements are carrying much more load than they should be.
The problem does NOT occur for the old generation elements (like SOLID45). Further, an equivalent KINH material model works fine for both the older elements and the new generation elements (like SOLID185 and BEAM188). For BEAM188 elements, the error does NOT occur if the quadratic shape function (KEYOPT(3)=2) is NOT used. The section properties also make a difference. These issues cause the reaction loads to be in error, too. Is this behavior due to a known error? |
Yes, Defect 42575 was filed and fixed in the daily build of ANSYS 11.0.<br> The MKIN behavior now matches the equivalent KINH behavior. ANSYS<br> build 11.0BETA UP20060119 was... |
Customer has Ansys 10.0 installed on Windows XP SP2. The installation worked without problems and he is able to read in his model. If he uses any option, he gets the following error message:
Error: bad screen distance "0.25i"
What is causing this error? |
In this case, it had to do with locale settings. User should try setting the numbers to use a decimal instead of a comma, or change to U.S. locale entirely to see if that resolves the problem.
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