Can I define composite shells in WB Simulation? |
WB Simulation 11.0 does not support direct definition of composite elements, such as composite shells. However, one can add composite definition to surface bodies in WB Simulation by performing... |
User gets the following error when trying to run ANSYS 11.0 on SuSE 10:
/opt/ansys_inc/v110/ansys/bin/linop64/ansys.e110: /opt/ansys_inc/v110/ansys/syslib/linop64/libgcc_s.so.1: version `GCC_4.2.0' not found (required by /usr/lib64/libstdc++.so.6)
Is there a fix for this? |
Rename /ansys_inc/v110/ansys/syslib/linop64/libgcc_s.so.1 to libgcc_s.so.1.orig<br><br>Then:<br><br>cp /lib64/libgcc_s.so.1 /ansys_inc/v110/ansys/syslib/linop64
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**** Entered By: rlange @ 12/12/2007 01:14 PM ****
######## WORK NOTES COPIED FROM INCIDENT 692434 ########
Q.
I performed an MFX simulation (2-way FSI between CFX and ANSYS) from t=0[s] to 2[s] and also performed a restart run at t=1[s] using the same model as a separate run. The results just after restart at t=1.1[s] are not the same for both models. Why is this?
A.
This is a known issue when the values transferred from ANSYS to CFX (displacements in this case) have not been fully converged within a timestep. It is only a problem when ANSYS is solving second (last). When performing a restart, in the first timestep ANSYS will ask CFX for the last displacement values that it sent from the previous run, since ANSYS does not store these values itself. When ANSYS solves last it will not have sent the most recent displacement values to CFX in the last timestep of the previous run, therefore it will not be restarting from the most recent displacements. This is not a problem when the displacements have been fully converged within the last timestep of the previous run, but if the displacements were still changing a restarted run will show different behaviour than a continuous run. QA Defect 31747 is associated with this issue. |
**** Entered By: rlange @ 12/12/2007 01:14 PM ****<br>######## WORK NOTES COPIED FROM INCIDENT 692434 ########<br><br><br>Q.<br>I performed an MFX simulation (2-way... |
User is trying to use the probe tool to get reactions at a contact pair between two rigid bodies in workbench, but the answer is always zero. Is this a bug? Is there a workaround? |
This is not a bug. It is a documented limitation. The way the probe tool calculates the contact reaction at contact element type 9 (for example) is as... |
Class 3 Error
SYMPTOM:
This error applies to two distinct setups.
1) A case run in parallel with stage interfaces may have errors in the calculation of the stage averaged pressure and the stage mass flow.
2) A case run in parallel when the mass flow rate is specified at a GGI Interface boundary may have errors in the calculation of the mass flow.
In most cases the error will not occur or will be small.
PROBLEM:
The CFX Solver makes an assumption that each GGI control surface is contained within the same partition as the corresponding face on the first interface side. This is not always true. In this case in a parallel run the CFX Solver will miss some of the control surfaces when building the averaged stage group pressure and the summarized stage group mass flow, or when the mass flow rate is calculated at GGI Interfac |
WORKAROUND:<br>No workaround is available.<br><br>FIXED IN:<br>ANSYS CFX Release 12.0. A custom executable for ANSYS CFX Release 11.0 SP1 is available on request.
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Class 3 Error
SYMPTOM:
In a multiphase calculation CFX-Post computes the same pressure force irrespective of which fluid is selected. This is consistent with the current documentation, which says that the pressure force is the same irrespective of which fluid is selected, but it can lead to the following bizarre result: if the user adds up the force due to each fluid they will get the wrong answer for the total force because the same pressure force will have been added twice, but the shear force is only included once.
PROBLEM:
This is due to an error in how forces are defined an |
WORKAROUND:<br>No workaround is currently available.<br><br>FIXED IN:<br>ANSYS CFX Release 12.0.
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**** Entered By: rlange @ 12/14/2007 04:53 PM ****
Q. I am trying to use intermediate transient results from CFX as part of a one-way FSI analysis in WB Simulation to perform a Structural/Thermal analysis. However, Simulation does not seem to be able to import the appropriate data. What could be wrong?
A. If only selected variables are stored in the CFX results file, it is possible that CFX-Post will not have enough information to compute the necessary data to transfer to WB Simulation. In order to get around this issue ask for standard output in CFX-Pre for the Transient results set. |
**** Entered By: rlange @ 12/14/2007 04:53 PM ****<br>Q. I am trying to use intermediate transient results from CFX as part of a one-way FSI analysis in WB Simulation to perform a... |
How to extract data from points along a specific line or polyline (here from a TurboChart line), where the data points locations
correspond to the locations of the intersection of the polyline with the grid points.
The procedure should be running in a CFX-Post session in batch. |
Currently we do not support PERL callbacks that will return variable values on an object, however this feature has been requested for future versions of CFX.<br><br>However, another... |
How to model the free water jets of Pelton turbines with a homogenous / inhomogeneous Euler-Euler model, plus the particle flow (in the jet) and erosion due to particles? |
Using a Beta functionality of ANSYS CFX, it is possible to set up a Euler-Euler 2-phase flow simulation with additional particles that will be tracked<br> in one of the 2 Euler phases... |
When importing geometries of relatively small impellers or diffusers of e.g. automotive turbochargers, that have diameters in the order of
10 ... 30 millimeters, BladeEditor may have problems building the geometry correctly or adding new features like revolving cut-offs and fillets. |
The internal Parasolid geometry kernel of DesignModeler, which is also used to create the 3D geometry model from a BladeGen BGD file,<br> works in units of [mm]. This can lead to... |
Does the variable "Pressure" in ANSYS CFX contain the turbulence term 2/3 * Rho * TKE? |
By default, the variable "Pressure" in ANSYS CFX contains the term 2/3 * Rho * TKE.<br>However, this term is substracted during the solver run before calculating other... |
Workbench freezes or crashes during intensive graphics operations (Slice plane, edit plane, etc.). Do you have any suggestions for troubleshooting this problem? |
The problem is most likely related to graphics.<br><br>- Run the DirectX diagnostic program to conveniently provide a detailed listing of the graphics and system... |
Class 3 Error
SYMPTOM:
In a PTM calculation with a stage interface, particles that cross the interface may appear to be clustered in regions where the grid is finer, thus producing more effect on the continuous phase in these areas.
PROBLEM:
Particles that cross the interface should continue from random azimuthal positions with the same axial and radial positions. However at present the code continues the particles from a random element face in the azimuthal direction, thus giving a concentration of particles in areas where the |
WORKAROUND:<br>No workaround is available.<br><br>FIXED IN:<br>ANSYS CFX Release 12.0. A custom executable for ANSYS CFX Release 11.0 SP1 is available on request.
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Class 3 Error
SYMPTOM:
If a particle transport calculation is run in parallel, then particles may bounce off the stage interface rather than continuing from a random circumferential position with the same radial and axial positions. This may not be noticed if all the tracks are not plotted and studied carefully in CFX-Post.
PROBLEM:
The CFX Solver incorrectly calculates control surface numbers for the particles as they cross the sta |
WORKAROUND:<br>Run the case in serial mode, if possible.<br><br>FIXED IN:<br>ANSYS CFX Release 12.0. A custom executable for ANSYS CFX Release 11.0 SP1 is available on request.
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Where can I download ANSYS BladeModeler 11.0 from? |
The ANSYS BladeModeler 11.0 application is incorporated within the ANSYS Workbench download. You need to download and install Workbench. You then need to set the licencing option under... |
Is it possible to undertake parallel post processing in CFX-Post 11.0? |
This is not currently possible with CFX 11.0. There are however, ongoing development plans with regards to parallel post processing in CFX-Post, especially with regard to large transient simulations.
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Is it possible to display Blade Suction Surface Pressure Contours in the Meridional View in CFX-Post 11.0? |
First define the blade surface mesh in terms of pressure side and suction side regions. After initialising within the Turbo CFX-Post Processor, you need to create a contour plot on the suction... |
In ICEM CFD, the pre-mesh quality check indicates negative determinants.
When trying to visualizing the problem, the cells appear fine. If the mesh is converted to unstructured and the mesh quality is checked again it passes the determinant check and no problems are detected. Therefore,
1)Is the mesh OK?
2)If the mesh really is corrupt, what can the underlying problem be - block structure, geometry or what?
3)Please explain why pre-mesh is bad while the unstructured mesh is fine. |
<br>The reason the Pre-Mesh Quality check reports negative determinants is due to the orientation of the multi-block block topology. The pre-mesh volumes are negatively orientated, even... |
Questions regarding the best practise for generating a turbine grid, including: What is the recommended cell size increase between rotating and stationary domains? Is it dependent on the interface used at this location (frozen, stage or transient)? Also do the radial grid nodes need to match 1:1 when using transient solution? |
There are general rules of thumb to follow regardless of the type of Multiple Frame of Reference (MFR) Interface you select.<br><br>1. The nodes on either side of the interface do not... |
How can you monitor the Torque and Thrust in a CFX 11.0 Solver calculation? |
You need to definine an expression for the Torque or Thrust at a particular region and then add a Monitor Point in the Solver Control to be able to monitor this in the Solver Manager. Torque is... |
In CFX-Post, how can you create a chart that will plot the change in force with respect to time for a transient simulation? |
To plot, for example, a Chart in CFX-Post showing the forces acting on the Hull of the ship with respect to time (or per transient iteration), you can do the following.<br><br>1.... |
How can you activate non-constant physics between domains? |
<br>By default, CFX-Pre always enforces the physics between fluid domains to be consistent. However, for some classifications of problem it is viable to define different physics in different... |
How do you get a mesh from ICEM into Workbench Simulation? |
<br>You first need to write out a mesh from ICEM in ANSYS format and then read this into ANSYS Finite Element Model. In FE Modeller you need to create the CAD surfaces from the mesh so that... |
Is it possible to use transient statistics in monitor point CEL expressions in CFX 11.0? |
It is not possible to use the transient average of a variable in a CEL expression. For example, to monitor the value of the transient average of the 1st component of velocity, it seems reasonable... |
Is it possible to set up a simulation in CFX-Pre entirely from the command line in batch mode? |
This is possible using the cfx5pre command and the '-e' switch, which allows command language (CCL) to be specified on the command line. For example:<br><br>cfx5pre... |