Customer has 1 seat of ANSYS LS-DYNA 9.0 and runs on a Linux machine.
Every time he tries to run our sample vme1.out, he gets an error that the license is already in use.
He is the only user. All licenses are available when he starts ANSYS LS-DYNA from the launcher. He then reads the input and gets the error.
Why is ANSYS attempting to check out an additional license? |
This appears to be a bug with ANSYS LS-DYNA 9.0 on the Linux Opteron platform (linop64). Customers with a single LS-DYNA task running ANSYS LS-DYNA 9.0 on a Linux Opteron client will have to... |
Why does it take so long to compute the RPSD. It is taking 10 times as
long as the PSD analysis itself. |
Theory Manual Equation 19.14-1 is used in computing RPSD. The number of calculations involved is approximately<br>proportional to modes**3 depending on the resolution set with STORE,PSD. ... |
Can the 3d magnetic element, SOLID117 be used in the Multi-field solver? |
Prior to ANSYS 10.0 morphing was not supported in the SOLID117 element. In 10.0<br>it is supported. If the magnetic field is non-linear (B-H curve) it will not be possible to<br>use... |
How do you use TB,SDAMP to specify frequency dependent damping in ANSYS 9.0?
I tried it on a simple model, but it didn't work. I tried to use the following commands:
TB,SDAMP,2,,1
TBFIELD,FREQ,610
TBDATA,1,0.002 |
The documentation should have indicated that it is necessary to<br>use TB,ELASTIC with TB,SDAMP. The values you input with SDAMP are<br>equivalent to Loss Factor values.
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How can I write out a vector to a file all on one line? |
The *MWRITE command can be used to write out a vector<br>on a single line. The input is shown below. An alternative for<br>a short vector would be to specify *VLEN,1 and then... |
Why aren't named selections defined in Design Modeler 9.0 being transfered to Simulation 9.0? |
The error is associated with the model being a multi-body part. If you "explode" the model in DM<br>the named selections will be transferred. This error is fixed in 10.0.
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Why isn't my total reaction force correct after a PSD analysis? When I list reaction forces with the PRNLD, PRRSOL or PRRFOR
commands, all forces are positive and the sum is unrealistically high. This is also the case when i do a shock response spectrum
analysis (Single-Point Response Spectrum (SPRS) Analysis) |
After a PSD analysis the reaction force at each support is a 1 sigma value. There is<br>no sign associated with it, so the sum of such reaction forces is meaningless, unless... |
Why do I get a message about the mesher straightening edges whenever
I mesh with SOLID117? |
That is a message put out by the mesher for any element that<br>requires straight edges. You should ignore it. The physical location<br>of the mid-side node is not used by SOLID117.
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My free surface calculation runs fine in serial, but when I run it in parallel it crashes on the first timestep. |
This is usually due to a partitioning problem. You should not have a parallel partition boundary parallel and close to the free surface itself in the domain. Also, if the free surface moves it... |
The user is having problems using space ball with Workbench 64-bit version (beta). Are there going to be any fixes in the service pack release to allow space ball to work in this environment? |
Spaceball is not supported for any 64-bit yet. There still are no drivers.
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How can I suppress error norm calculations in Workbench 9.0 for
a model with SOLID5 elements (created with a command snippet)? The xml
retrieval is failing because this element doesn't have error norms. |
Setting a variable 'allow null results' equal to 1 will solve the problem.
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How can I make a contour plot using gray scale? |
Go to PlotCtrls: Style> Colors> Create Color Map.<br>Using this menu I created the color map below in a file named zhiyu.map,<br>which can now be fine-tuned with an... |
Why is a modal analysis of a very small MEMS piezoelectric resonator missing
modes and taking too long? |
Your system of uMKS may be giving the solver problems due to<br>small mass density values in Kilograms/cubic micron. I would like to<br>propose a different unit system:<br>uM... |
Why can't I apply a single remote force to multiple parts in Workbench 9.0? |
This is a known architectural limitation that has been removed in Workbench 10.0.
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How can I animate a sequence (load steps) in Workbench 9.0? I have results from 12 load steps
that I want to animate. If I select the animate button in Workbench and (for example) I have the 12th
load step selected, the animation will be displayed for only load step 12, ie. the animation will sequence
the results linearly from 0 to the load specified in load step 12 only and skip the results from load steps 1 thru 11.
How can I animate the results from each load step 1 thru 12? |
This works in Workbench 10.0, which is due out shortly. In the<br>meantime, you could move over to the traditional interface and<br>use PlotCtrls (top menu bar): Animate> Deformed... |
Customer is getting the following error when trying to install CFX 10.0 service pack on a Linux machine:
Can't locate CFX5/Output.pm in @INC (@INC contains: /glb/apps/3rdparty/CFX/CFX-
10.0/bin//perllib /glb/apps/3rdparty/CFX/CFX-10.0/bin/../../Shared/perl-
5.8.0/lib/5.8.0/i686-linux /glb/apps/3rdparty/CFX/CFX-
10.0/bin/../../Shared/perl-5.8.0/lib/5.8.0/i686-linux
/glb/apps/3rdparty/CFX/CFX-10.0/bin/../../Shared/perl-5.8.0/lib/5.8.0
/glb/apps/3rdparty/CFX/CFX-10.0/bin/../../Shared/perl-5.8.0/lib/site_perl/
5.8.0/i686-linux /glb/apps/3rdparty/CFX/CFX-
10.0/bin/../../Shared/perl-5.8.0/lib/site_perl/5.8.0/i686-linux
/glb/apps/3rdparty/CFX/CFX-10.0/bin/../../Shared/perl-5.8.0/lib/site_perl/5.8.0
/cfxhome/cfxir/perl/Linux/lib/5.8.0/i686-linux
/cfxhome/cfxir/perl/Linux/lib/5.8.0
/cfxhome/cfxir/perl/Linux/lib/site_perl/5.8.0/i686-linux
/cfxhome/cfxir/perl/Linux/lib/site_perl/5.8.0
/cfxhome/cfxir/perl/Linux/lib/site_perl .) at cfx5info.pl line 233.
BEGIN failed--compilation aborted at cfx5info.pl line 233.
Installation complete, press ENTER to continue:
Removing temporary directory ...
What is causing the install of the service pack to fail? |
The customer thought that the service pack was a complete installation and uninstalled CFX 10.0, which is what caused the problem.<br><br>The CFX service pack is a modification to the... |
Turbo Post fails to display the blade-to-blade view properly. It appears as a line rather than a 2-d plot. |
This could be caused by the fact that all or some of the hub region coincides with the axis of rotation. This has been enhanced for release 11.0. An Environment Variable can be specified to get... |
How can I write a script in CFX-Post 10.0 to make a line for each time step where the endpoints are dependent on expressions? |
If you use the getExprVal function, this function turns cel expressions into perl variables. i.e.<br><br>!$Mup1 = getExprVal('up1hz');<br><br>Now the variable... |
**** Entered By: rlange @ 12/16/2005 01:48 PM ****
Q. How can I do a CFD simulation that demonstrates vortex shedding?
A.
Vortex shedding is the continuance of a flow disturbance initiated by some instability in the system or surroundings. In a CFD simulation, the disturbance can be initiated in the computer simulation through numerical roundoff error, but more typically it must be introduced through the setup of the analysis.
One approach is to perform the analysis in two stages. Consider the classic geometry often used for illustrating vortex shedding, that of flow past a cylinder. The problem domain should extend a length of at least 10 characteristic diameters downstream, and up to 30 is reasonable, especially for the higher Reynolds number cases. The CFX outlet boundary condition of average static pressure is best for these simulations. During the first stage, the cylinder is rotated (i.e. it spins with a moving wall condition) and a solution obtained (this could be done in pseudo time, rather than real time). This becomes the initial condition for the vortex shedding analysis itself. Upon restart, the cylinder rotation is set to zero, and all other boundary conditions are maintained. It should then take a few cycles to get to "steady" behavior.
Next, how do we capture this phenomenon? A suitable time step as well as a suitable frequency at which to save results must be chosen. The dimensionless cylinder shedding frequency is known as the Strouhal number: St= fD/U, where f is the shedding frequency, D the characteristic diameter, and U is the velocity. From Frank White's Viscous Fluid Flow, Figure 1-8 (Figure 1-8 is an attachment to this solution: StvsRe.pdf), which relates the Strouhal number to the Reynolds number, we know that the Strouhal number for RE=150 is about 0.2, for example. Actually, this value of 0.2 is pretty accurate up to a Reynolds number of 100,000.
So fD/U = 0.2, and with, say, D~.2 ft and U=.006895 ft/sec, we |
**** Entered By: rlange @ 12/16/2005 01:48 PM ****<br>Q. How can I do a CFD simulation that demonstrates vortex shedding?<br><br>A.<br>Vortex shedding is the continuance... |
Are the reactions in Simulation calculated about the global origin? |
No. In Simulation Release 10.0, the summation location is roughly the centroid of all of the nodes that form the support. To obtain the reactions about a specific location, you can insert a... |
Why do the material properties that I defined in WorkBench not transfer over to ANSYS when I click the ANSYS environment button in the project tab? |
You must include a result request (either stress, strain, etc.) in the solution branch so that ANSYS can identify the type of physics being used.
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How do I get ANSYS to output the global stiffness matrix of a part? |
You can use the HBMAT command to output the global stiffness matrix in the Harwell-Boeing format.<br><br>HBMAT, Fname, Ext, --, Form, Matrx, Rhs<br><br>Writes an assembled... |
Why is there a difference between the stress plots for PIPE18 (elastic) and PIPE60 (plastic) elements? |
The way the stresses are computed for the PIPE18s and the PIPE60s are very different. They are pretty much the same for the straight pipes, which is why you don¿t see a significant... |
What geometry files can be imported into Workbench without any addon licenses? |
The IGES and STEP reading capability is just a Workbench feature for all solver<br>products of Professional and greater (also ANSYS PrepPost). The Geometry Interface<br>for STEP was... |
How can I assure that my existing components (ROD and CAP) use the lowest entity number? |
The ANSYS commands to assure that nodal components ROD and CAP have the lowest node<br>numbers in the model... |