Class 3 Error
SYMPTOM:
The variables 'Heat Flux' and 'Wall Heat Flux' available in CFX-Post can be significantly different at fluid-solid interfaces boundaries.
PROBLEM:
The variable 'Wall Heat Flux' is calculated by the solver as a boundary only hybrid field and as such is subject to averaging issues as well as mesh edge effects. The variable 'Heat Flux' is based on the integration point energy flows which are directly read from the results file by CFX-Post. This is why the plots of the two variables, and any quantitative calculations performed using these variables, will be different. For quantitative calculations the more accurate 'Heat Flux' variable is recommended for boundaries in any Fluid Domain. However, the user should also ensure that convergence levels are tight (ideally maximum energy residuals < 1E-3). The actual boundary heat flows across fluid-solid interfaces can be monitored in the Solver Manager.
Note that the 'Heat Flux' variable is currently absent from the results file for Solid Domai |
WORKAROUND:<br><br>FIXED IN:<br>Release 11.0
|
Question:
I am running Simulation and need to add some post processing plot commands via a Command Snippet. Do I need to do anything special to get those plots into the command tree.
Answer:
There are two requirements to have the post processing command snippet plots returned to the command tree. First, the tree must have at least one post processing command. This is a trigger for Simulation to return information from ANSYS to Simulation. Second, a /SHOW,PNG
command must be included. Since ANSYS runs in batch mode, the program needs somewhere to send the plotting commands. The /show,png is necessary to give the plot somewhere to go. For the post processing, Workbench collects all the png files and places them as children under the first command snippet. |
Question:<br><br>I am running Simulation and need to add some post processing plot commands via a Command Snippet. Do I need to do anything special to get those plots into the command... |
After installing a new FLEXlm for SolidWorks, the ANSYS FLEXlm License Manager doesn't work anymore.
Opening FlEXlm LMTOOLS Utility, there is no ANSYS FLEXlm License Manager listed, but
checking Control Panel->Administrative Tools->Sertvices, one can still see the ANSYS FlEXlm License Manager listed as a Service.
A reinstall of the ANSYS FLEXlm doesn't resolve the problem.
What causes this? |
The cause is unknown, since we do not know how SolidWorks updates their FLEXlm License Server.<br><br>What has happened is the following Registry keys and subkeys for the ANSYS FLEXlm... |
When trying to run cfx5pre on Redhat Enterprise ws 4 we get the following:
/opt/az/supported/cfx/CFX-10.0/bin/linux/PreGui_ogl.exe:
/opt/az/supported/cfx/CFX-10.0/lib/linux/libgcc_s.so.1: version `GCC_3.3'
not found (required by /usr/lib/libstdc++.so.6) Warning!
CFX-PRE exited with return code 1
Note that we can run it on the old RHEWS 3 |
<br>As you are perhaps already aware, Redhat Enterprise WS 4 is not an officially supported problem.<br>Please do the following:<br>Try setting the following Environment variable... |
I would like to specify orthotropic thermal conductivity in a solid domain using CFX. |
<br><br>Please note that this approach works only if all solid interfaces are 1-1.<br><br>To use Orthotropic Thermal Conductivity you need to edit the CCL definition of a... |
Where can I find properties for modelling the combustion of JetA liquid sprays? Where can I get good reaction kinetics for fuels such as kerosene, JetA etc ... |
<br><br>Most of these types of fuels are variable mixtures of heavier hydrocarbons and getting good property information can be difficult. The reaction mechanisms for JetA/air and... |
What is the difference between using a Rotating Domain and a Stationary Domain with rotating walls in CFX? |
<br>A Stationary Domain with rotating walls is only valid if the wall motion is entirely tangential. If there is any normal component to the wall motion, the fluid will not... |
I have CFX results file from a simulation with several million nodes. When loading this into CFX-Post I get an error:
ERROR
Unable to load file:
<path>/<file>.res
The only file types which CFX-Post can currently read are:
1) CFX Results or Definition files
2) CFX Mesh files
3) CFX-4 Dump files
4) CFX-TASCflow files (must have grd/rso, bcf and prm files)
5) CGNS Files |
<br>It is likely that you have reached the 2GB file size limit for 32-bit systems. Check to see if the res file is larger than 2GB and if so, you will need to post process it on a 64-bit... |
Class 3 Error
SYMPTOM:
In a single phase calculation, the massFlowAve() CEL function for any global variable in the solver does not return the correct value.
PROBLEM:
A fix was added in Release 10.0 to ensure that multiphase flows used the bulk mass flows when no fluid was specified in the mass averaging operation. However, this fix introduced a new bug for single phase flows, namely that all mass flow averaged global variables are incorrect. Instead of returning the mass flow average, the mass averaging operation is silently switched to an |
WORKAROUND:<br><br>FIXED IN:<br>Release 10.0 SP1.
|
In the installation manual for CFX10 it says:
Distributed parallel using MPICH cannot be set up using a mixture of UNIX and Windows machines.
Does this apply if it is just the master node on the Windows machine and all the compute slaves on a linux cluster? If so, is the only way that this machine configuration can be used to run with PVM? |
On Windows platforms we use MPICH-NT while on UNIX/Linux platforms we use MPICH. MPICH-NT and MPICH are not compatible. So you cannot use MPICH where you are using both Windows and Linux even if... |
Class 3 Error
SYMPTOM:
When the thermodynamic properties for a Fixed or Variable Composition Mixture are overridden using the Mixture Properties settings, they are not taken up by the solver. Instead, it appears that the ideal mixture property, based on the local mass fractions, is used.
PROBLEM:
Overriding thermodynamic mixture properties for fixed or variable composition mixtures does not work in Release 10.0. The solver will always use the Ideal Mixture |
WORKAROUND:<br><br>FIXED IN:<br>Release 10.0 SP1.
|
What does the following error mean?
+--------------------------------------------------------------------+
| An error has occurred in cfx5solve: |
| |
| Unable to start the PVM daemon on host ims1388 (IMS-1388). This |
| may indicate that the PVM daemon is already running on that host, |
| or that it left files in /tmp on that host because it did not exit |
| cleanly last time it was run. |
+--------------------------------------------------------------------+ |
Possible causes are:<br>(1)<br>The pvmd daemon uses temporary files when in operation. Sometimes these temporary pvm files can remain and cause problems.<br>On a unix machine... |
Customer gets the following error when trying to start ANSYS 10.0 on Fujitsu(Model: PRIME Power650 with 8 CPUs) running Solaris v9.
ansys.e90 ' cannot find /usr/lib/sparcv9/lpgdl2.so.1
Killed
What is causing this error? |
Customer did not install parallelnavi. Since they did not install it, Ansys can not find lpgld2.so.1, which is part of the parallelnavi package.<br><br>The fjpp versions of Ansys 9.0... |
Class 3 Error
SYMPTOM:
If the Latent Heat option for setting the latent heat of evaporation of particles (liquid evaporation model) is used in conjunction with User Specified Mass Transfer, the results are incorrect.
PROBLEM:
This problem arises because the CFX Solver incorrectly uses the Automatic option (which uses the Reference Enthalpies defined for the materials) for latent heat calculation |
WORKAROUND:<br><br>FIXED IN:<br>Release 10.0 SP1.
|
How do I setup a simulation in CFX 10.0 with R134a? |
R134 is just a material which we support with RGP files and with the Redlich Kwong equation of state.<br>Thus it should be fairly simple to set up a simulation using... |
I have a problem with different mass flow across interface in CFX-5.7.1. |
<br>1) By default, pitch ratio is computed as simply the area ratio of side 1 and side 2.<br><br>2) This means that by default the side1/side2 area should only differ in the... |
QUESTION:
The attached article (01432505.pdf in 2D_AC_resistance_time_int_pot_term_conditions.zip) presents an analytical solution of AC resistance of a straight solid circular conductor . It concludes that the AC resistance increases with current frequency (as a function of square root of the frequency). I also found some other papers showing the same profiles. I wonder whether you could take a look at the article as attached and have some comments on this issue. I also wonder whether you provide any related benchmark problems to verify the accuracy of ANSYS EM calculation.
ANSWER:
I use two methods to obtain AC resistance:
1) Use the time integrated electric potential available in the magnetic scalar potential elements (PLANE13, PLANE53, SOLID97). An example is included in the attached file named:
2D_AC_resistance_time_int_pot_term_conditions.zip
The parameterized input file (wire11.inp) creates a 2D quarter symmetry model of the cross section of a solid circular conductor (currently using r = 1mm). Using terminal conditions - the time integrated electric potential (which is actually the integral of physical voltage) and the applied current - I can evaluate the complex impedance of the conductor at each investigated frequency. The attached macro (indctnc0.mac) contains the APDL that evaluates AC resistance by converting the time integrated electric potential to physical voltage for use in the impedance calculation (z=v/i).
The real part of the calculated complex impedance (the AC resistance) is plotted versus frequency in the file001.png. Compare the results shown in this plot to those for a 1mm wire shown in Figure 4 in 01432505.pdf. It looks to me like the agreement between the ANSYS result and those obtained in the paper by Gatous and Filho is quite good.
I included a simple rho*L/A calculation of the DC resistance in my input file (parameter r_DC) which evaluates to 5.41e-3 ohm/m. At the lowest investigated frequency (2096 H |
QUESTION:<br><br>The attached article (01432505.pdf in 2D_AC_resistance_time_int_pot_term_conditions.zip) presents an analytical solution of AC resistance of a straight solid circular... |
How can you improve the convergence locally in a specific domain in the CFX 10.0 solver? |
<br>1) The convergence can be locally improved by setting a source term for a subdomain that covers a specific domain with slow convergence.<br>The value of the source term should be... |
How can I calculate contact forces (contact reactions) in Traditional ANSYS? |
WB ds.dat includes a POST1 procedure that can give the summed force at a contact (or target) surface. You need to know the REAL and TYPE attributes of the contact/target elements (REAL=5 and... |
What should be the inlet boundary conditions when using the RANS model for a turbulent jet in CFX 10.0? |
The behavior of the jet is very much dependent on the inlet conditions and mesh resolution around the jet's orifice. To prescribe a turbulence intensity on the inflow is just not good... |
In my plasticity analysis, issuing KUSE,-1 gives more accurate results
than the KUSE,0 default, even if I have large deflection (NLGEOM,ON)
turned on. Is this a known error? |
Actually, this is not an error at all. The default KUSE setting for<br> plasticity uses the ELASTIC stiffness at the start of each substep.<br> Issuing KUSE,-1 can give... |
I'm trying to create a multifield solver demonstration of induction heat expansion of a part followed by shrink fit onto a shaft after the part cools. I want to use 117 because ultimately I anticipate they will want to model general 3D geometry + iron.
My model consistently gives me an error message when I try to solve:
Offset 2 out-off-bounds.
When I use SOLID97, it runs fine. But I want to use 117 because of possible material interface issue.
Is there anything I can do to work around the problem? |
If any element type besides SOLID117 is active when the emag solution is attempted, it will fail. SOLID117 cannot be used with any other element types. Check the element type assigned to each... |
What is the meaning of "Target Minimum Coefficient Loop" and "Target Maximum Coefficient Loop" in the Adaptive Timestep method? |
<br><br>Timestep will be increased if actual number of coefficient loops is less than the target minimum.<br>Timestep will be reduced if the actual number is larger than the... |
Will any plugins be available in Workbench 10.0 SP1 on Linux 64-bit? |
The 32-bit version of Workbench should be supported on 64-bit Linux in the next release.<br> However, no translators ( Plugins / readers ) will be supported at this time.
|
**** Entered By: rlange @ 10/21/2005 04:46 PM ****
Q. I am planning to run an FSI analysis with the ANSYS/CFX MFX solver. How much flexibility do I have in the systems of units used in ANSYS and CFX.
A. The key is to recognize that the load transfer occurs in the Solver portion of CFX, and so the forces transferred will be in Solver units. These can be controlled to some degree in CFX-Pre. However, it must be kept in mind that the units of force are derived, not specified. That is, if you choose [lbm] for a mass unit and [in] for a length unit in CFX, the forces are in [lbm*in/sec] so pressure is [lbm/in-s].
Convert the value of EX, Modulus of Elasticity, in ANSYS to the same system of units used in CFX. If the modulus in ANSYS is 30E+6 [psi], for example, multiply it by a factor of 386.04 [lbm-in/lbf-s2]. Also fix the units of density so that it is in terms of [lbm/in3], not [lbf-s2/in4].
It is best to use the SI system of units in both ANSYS and CFX, but any system with Gc=1 will work. |
**** Entered By: rlange @ 10/21/2005 04:46 PM ****<br><br>Q. I am planning to run an FSI analysis with the ANSYS/CFX MFX solver. How much flexibility do I have in the systems of... |