QUESTION:
Do you have an example illustrating the procedure for performing a 'small signal' frequency response analysis of a hard disk drive voice coil motor (HDD VCM)? We wish to be able to create a bode plot of the transfer function using coil current as input, read-write head displacement as output.
ANSWER:
Please review the attached presentation and use the working files discussed on the second to last slide to automatically recreate the model and coupled field solution. It's fully parameterized and the model/design is very simple/hypothetical to illustrate the solution procedure.
I had problems getting a bode plot in ANSYS (I will investigate the reasons for this later), but the data that one would use to create one outside ANSYS is certainly available from the structural results file. |
QUESTION:<br><br>Do you have an example illustrating the procedure for performing a ¿small signal¿ frequency response analysis of a hard disk drive voice coil motor (HDD... |
Class 3 Error
SYMPTOM:
The Solver calculates incorrect source terms from particles to the continuous phase at partition boundaries, leading to overall sources that are too large. For example, the total mass source may be greater than the total mass flow rate of particles. Smoothing of particle vertex variables is similarly affected at partition boundaries.
PROBLEM:
This is due to a bug in the CFX Solver regarding communication of smoothing information between t |
WORKAROUND:<br>The workaround for this is to run in serial mode, or to use the default non-smoothed sources.<br><br>FIXED IN:<br>Release 11.0. Custom executable for Release... |
Class 3 Error
SYMPTOM:
The Liquid Evaporation Model can give incorrect answers if the user-specified latent heat option is used, without the Light Oil Modification, as the value will not be used. If the Automatic option is used for getting the latent heat, then there is no problem.
PROBLEM:
This is due to a bug in the CFX Solver in setting the actual latent heat to be used, which varies with |
WORKAROUND:<br>The workaround is to set the reference enthalpies correctly in the material specification, and to then use the Automatic option.<br><br>FIXED IN:<br>Release... |
Class 3 Error
SYMPTOM:
When CFX-Post is used to perform calculations of quantities that are functions of Turbo vector variables (e.g. Theta Direction X, Y, Z), they find that the values of these quantities, which should change as different timesteps are loaded, stay the same.
In addition, the colouring of some objects (such as boundaries) with these quantities is not updated after each timestep.
PROBLEM:
This is a problem associated with the initialisation of Turbo variables when not in Turbo Post mode. If 'Turbo Initialisation' had not been performed, the variables associated with Turbo Post do not get updated when transient results files are loaded through the Times |
WORKAROUND:<br>Re-initialise the Turbo variables (Turbo>Initialise All Components) after each timestep is loaded to ensure the values are current.<br><br>FIXED IN:<br>Release... |
I have a licensing problem with ANSYS CFX 10. |
<br>The attached pdf describes some of the common licensing problems that can occur with ANSYS CFX 10.0, and ways of diagnosing the problems.<br>Any updates and comments are welcomed.
|
How can I use an equation based 2d profile to do an extrusion in DesignModeler (DM)? |
The steps to do this process are as follows:<br><br>1. Make the coordinates file per the DesignModeler help. Either an ASCII<br>text editor or Excel with Save as text option can... |
When trying to start Workbench on a Windows 2000 Service Pack 4 machine the user receives the following errors:
+++++++++++++++++++++++++++++++++++++++++++++++++++
Line: 2400
Char: 8
Error:
Code: 8007007f
Source:
Script: var WshShell = new ActiveXObject("WScript.Shell");
____
| OK|
++++++++++++++++++++++++++++++++++++++++++++++++++++
And:
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
ANSYS Workbench:AnsysWBU.exe - Entry Point Not Found
The procedure entry point DoOpenPipeStream could not be located in the dynamic link library ScrRun.dll
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
What causes this? |
The file C:WINNTSystem32ScrRun.dll was version 5.0. It needs to be version 5.6.<br>To get the 5.6 version, go to Microsoft's website and download the 5.6 Scripthost.<br>English... |
What can cause the following error?
Launcher.exe - Entry Point Not Found. The procedure entry point ??0?basic_stringstream@DV?$char_traits@D@_STL@@V?$allocator@D@2@@_STL@@QAE@G@Z could not be located in the dynamic link library stlport_vc6.dll. |
There may be another stlport_vc6.dll file residing in another directory on the system hard drive¿<br> Search the machine for multiple stlport_vc6.dll files.<br> If one... |
Q.
Is there known cases where the mid-surface feature in DesignModeler will fail? Are there workarounds?
A.
There are a few situations where the mid-surface might fail or result in unexpected geometry. These cases are described thoroughly in the word document attached. |
Q.<br><br>Is there known cases where the mid-surface feature in DesignModeler will fail? Are there workarounds?<br><br>A.<br><br>There are a few situations... |
I have set the environment variable
"CFX5_REFINER_NO_TRICOLUMNS=1"
but mesh adaption in a model with inflated mesh fails with the message,
"ERROR: The inflated layer topology is inconsistent" |
<br>If you launch the solver manager directly from CFX-Pre the environment variable setting is not carried through to the Solver Manager. Therefore after setting the environment... |
Q. If user has just one Environment branch and he updates the geometry using "Geometry Parameter Values", things update as expected.
If he duplicates the Environment branch and updates geometry, then Simulation mysteriously creates additional environment branches
beyond what was created by user originally.
A. This was a defect (#46734) that has been corrected for 11.0. It appears to be related to a "winding body" in the geometry branch and a "magnetic flux parallel" load and "conductor winding body". Removing these items seems to overcome the problem. There is no other known workaround at 10.0A1. |
Q. If user has just one Environment branch and he updates the geometry using "Geometry Parameter Values", things update as expected.<br>If he duplicates the Environment branch... |
I start ANSYS CFX 10 using the desktop icon. When I last used ANSYS CFX 10 (last Friday) it was working fine; today (Monday) I get an icon appearing in the Task bar which quickly goes away again and the Launcher does not open. I am running on a PC with Windows XP installed and the machine is also the license server. |
To see if any further error messages are produced open a DOS Command Prompt window and change to the ANSYS CFX 10 installation directory (which by default will be c:program filesansys... |
Q. Has ANSYS done any bench marks between amd 64 bit with ddr 400 ram vs intel 64 with ddr2 ram ? I am not too sure of the current mainboard situation and if it is even mainboard related, but will intel machine perform faster based on the ram alone, if all other factors are as equal?
A. The memory speed is an important factor in comparisons between 2 systems, whether AMD vs. Intel or Intel vs. Intel, but bus speed and processor speed are also important. Often a given processor gets put on a cheaper, slower board with slower memory. This happens often with the lowest cost systems. Then the processor is a lot slower than expected. If an Intel em64t system has equal memory size to an AMD system the em64t system will win (The fastest em64ts - 3.6 - 3.8 Ghz). This is especially true for sparse solver performance in ANSYS. In the pcg solver memory speed is more important so the 2 processors are more equal in that case.
Both AMD and Intel make fast processors. Both have their strengths and weaknesses. In either case the recommendation is to purchase a 64 bit machine with at least 8 Gbytes of memory, 2 processors and the fastest bus speed. 800 Mhz for Intel is about equal to 1.6 Ghz speed on AMD because they mean slightly different things. But a motherboard that runs at 500 Mhz is not going to run ANSYS nearly as fast as the 800 Mhz boards (and soon to be 1600 Mhz Intel motherboards). It is worth investing in memory on any system. It is THE performance differentiator. Given that both AMD and Intel have equivalent configurations, it comes down to price. |
Q. Has ANSYS done any bench marks between amd 64 bit with ddr 400 ram vs intel 64 with ddr2 ram ? I am not too sure of the current mainboard situation and if it is even mainboard related, but will... |
How can I use geometry created using the simple grid command in CFX-4, in a CFX-10 calculation? |
If the CFX-4 command file containing the simple grid commands is "m01.fc", from the CFX-4 command line execute the command,<br><br>parsolve4 -msh -c... |
In a mixing vessel using MFR, where there is a rotating impeller with known torque on the blades. How can I find the rpm of the impeller? |
Suggest that you carry out 3 runs of CFX for the rotating impeller MFR calculation.<br>1. Run1 - you specify an initial guess for the angular velocity omega, and the code will then calculate... |
How to force an application to use a library from a specified path instead from the standard search path?
Reason is, conflict with a library that was found first in the search path. |
e.g. for a bash:<br><br>setenv LD_PRELOAD /home/cfx/ansys_inc/v100/icemcfd/linux/lib/libstdc++.so.5<br>run_program
|
Are there any examples of using the GAP and FSLIDE features of COMBIN40 elements? |
Yes, please see the attached ANSYS 10.0 SP1 example. The model consists<br> of a single COMBIN40 element. The order of the nodal connectivity determines<br> how the element... |
How can I chart the variation (in time) of the interface on a vertical line in my 3D CFX 10.0 sloshing simulation? |
<br>If you want the position of the interface on a vertical line you can:<br>1. create the vertical line<br>2. create a point with the method 'Variable Maximum',... |
Class 3 Error
SYMPTOM:
The random numbers generated by the code for determining turbulent dispersion eddies, droplet break-up and particle behaviour at stage interfaces may be correlated between different particles. The problem is most apparent for the stage interfaces, where particles may bunch after crossing the interface, because many more random numbers are used in the other applications.
PROBLEM:
This is due to a bug in the CFX Solver in creating the seeding for the random numbers, which needs to be controlled so that solutions, although stochastic, are the same in parallel and on all operating systems. Note the problem does not affect the random numbers generated for partic |
WORKAROUND:<br>There is no workaround.<br><br>FIXED IN:<br>Release 11.0. Custom executable for Release 10.0 available on request.
|
Class 3 Error
SYMPTOM:
The integrated quantity function massFlowAve() can return different values when applied in the CFX-Solver and when used in CFX-Post. The differences can be location and problem dependent.
PROBLEM:
This is due to an inconsistency in the algorithmic behaviour of the function. In the CFX-Solver, the averaging is applied using local absolute values of mass flows, whilst in CFX-Post the averaging is applied using local signed values. The sign convention for mass flow on boundaries is (-ve) if the flow is leaving the domain and (+ve) if entering. For internal locators generated in CFX-Post, such as planes, the sign convention can be arbitrary.
Note that the function massFlowAveAbs() is available in CFX-Post and reproduces the current behaviour of massFlowAve() in the |
WORKAROUND:<br>There is no workaround.<br><br>FIXED IN:<br>ANSYS CFX Release 11.0.
|
QUESTION:
Do you have any instructive acoustics models?
ANSWER:
Two models are attached to this incident:
1) simple rigid baffle sends acoustic radiation to infinite boundary
2) Transient audio speaker coupled field model. Magnetostructural coupled field PLANE13 used to model the VCM. Speaker cone serves as radiation source. |
QUESTION:<br>Do you have any instructive acoustics models?<br><br>ANSWER:<br>Two models are attached to this incident:<br>1) simple rigid baffle sends acoustic... |
In particle tracking in CFX 10.0, why can the particle source coefficient affect the solution and not just convergence? I thought that in CFX-10.0, source coefficients only affected convergence. |
1. The particle source coefficient affects the accuracy of the track calculation and can therefore change the solution.<br><br>This can be explained by the fact that particle momentum... |
How can I get the gradient of some transient statistics variable in CFX 11.0? |
In a CEL function (user fortran), the gradient of a variable would be obtained by calling USER_GETVAR:<br><br> CALL USER_GETVAR(VariableName,<br> & ... |
Menu items for ANSYS Workbench aren't created correctly in the Pro/E menu and appear as follows:
PI_MENU_START_APP
PI_MENU_START_APP2
PI_MENU_APP_HELP
PI_MENU_ABOUT_PLUGIN
Workbench starts when selecting PI_MENU_START_APP, but how can I get the correct names to appear in the menu? |
Registering the plugin should allow the names to appear correctly in the Pro/E menu.<br><br>From the Windows command prompt, change directory to ¿C:Program FilesAnsys... |
Is there a way to determine the volume of an element following a structural solve? The postprocessor simply reports the volume of the elements as they were meshed, before deformation. |
Yes, alhtough this is not something that is directly available in the ANSYS postprocessor. There is however, a way to do this using the UPCOORD command. Using the UPCOORD command in a subsequent... |