How can I retrieve the average heat flux through a surface in Simulation? |
For a temperature sink (constrained temperature), the total heat flow could be obtained by making a named selection for the surface and then referencing that in a Commands Object in the Solution... |
What is the Quality Factor in FEModeler mesh metrics? Are the Quality Factor in FEModeler and the Workbench Shape Metric in Simulation the same? |
The quality factor is computed for each element of a model (excluding line and point elements). This metric is based on the ratio of the volume to the edge length for a given element. A value of 1... |
Why is ESLN so much slower in ANSYS 11.0? |
The slowness in 11.0 was due to a bug fix in the ESLN logic (defect 44332) which added a check to see if the node on the element is an internal node (e.g. the third node of a beam element). The... |
Why is my static cyclic-symmetry analysis with axisymmetric loading in ANSYS 11.0 solving for all possible 49 harmonic indices? |
This behavior has been corrected by fixes for defect 63441 in ANSYS 12.0. The solution still evaluates all 49 harmonic indices to determine if they are significant, but the computation now takes a... |
I am trying to set up a steady-state ANSYS-CFX FSI run and would like
to have an example CFX definition file and ANSYS input file. I'd also to
interested to know how the number of stagger loops and maximum number of
timesteps affects the overall number of steady-state iterations in CFX. - KSVIHLA |
A zipped archive with a complete steady-state example is attached.<br><br>CFX solves for the specified number of maximum iterations before doing an update with... |
I am running a simulation in parallel in ANSYS CFX 11 which features a moving mesh with a GGI interface.
I noticed that the overlap nodes are very high for my parallel partitions and I can't reduce this by changing to
a different partitioning method.
If I run the case without moving mesh, the overlap nodes are much reduced.
What's going on? |
<br><br>If the mesh on either side of an interface is moving, then all nodes on that interface are marked as overlap. `Overlap¿ simply means that a node (and it¿s... |
Does initial stress with the INISTATE command work with BEAM188? |
Yes, the test below shows that the addition of initial stress from a loading returns the BEAM188 to its neutral position when applied with that... |
I tried to run a simulation in ANSYS CFX 11.0 but the run failed with the following message:
SYMASS_ZIFCS_EL : The solver ran out of temporary space while building a linked list for a domain interface.
Try setting the expert parameter "topology estimate factor zif" to a value greater than 1.0. Values higher than
1.2 should not be necessary.
When I tried to insert an expert parameter from the definition file editor in the Solver Manager, I only saw topology estimate
factor. Is this the same parameter and if not, how do I set topology estimate factor zif? - KSVIHLA |
The expert parameters topology estimate factor and topology estimate factor zif are separate expert parameters.<br><br>Only topology estimate factor is available in the drop down list... |
Why won't the input below with COMBI214 converge or give correct answers?
/PREP7
ET,1,MASS21,0,0,2
R,1,1.0
ET,2,COMBI214 ! ELEMENT TYPE # 3: BEARING ELEMENT
KEYOPT,2,2,1 ! YZ PLANE
KEYOPT,2,3,0 ! ELEMENT IS SYMMETRIC
R,2,10,10,10.0,10.0,, ! REAL CONSTANTS ( K11,K22,K12,K21) NO DAMPING
/COM, NODES
N,1, 0.0, 0.0, 0.0
N,2, 0.0, 1.0, 0.0
N,3, 0.0, 0.0, 1.0
/COM, ELEMENTS
/COM, MASS
TYPE,1
REAL,1
E,1
/COM, BEARINGS
TYPE,2
REAL,2
E,2,1,3
ALLSEL,ALL
FINI
/SOLU
D,1,UZ
D,ALL,UX ! NO TRACTION
D,2,ALL ! SECOND NODES OF BEARING
D,3,ALL ! SECOND NODES OF BEARING
OUTPR,ALL,ALL
ANTYPE,TRANS !NONLINEAR TRANSIENT DYNAMIC ANALYSIS
!NLGEOM,ON ! LARGE DEFLECTION OPTION
NROPT,FULL
KUSE,-1
NEQIT = 30
TIME,1.0
F,1,FY,1.0
KBC,0
NSUBST,10,10,10
LSWRITE,1 ! WRITE LOAD STEP FILE 1
TIME,10.0
F,1,FY,0
KBC,1
NSUBST,90,90,90
LSWRITE,2 ! WRITE LOAD STEP FILE 2
FINISH
/SOLU
OUTRES,ALL,ALL
OUTPR,ALL,ALL
LSSOLVE,1,2,1 ! READ IN LOAD STEP FILES 1 and 2
FINISH |
This is defect 63544. The problem was caused by node orientation. Typically, the i and k nodes are at a negative offset to the node on the centerline. In this model, they have a positive offset,... |
I would like to apply a CFX temperature load to an ANSYS set of surfaces from a number of CFX boundary conditions.
How can I do this? |
<br><br>Either of the following two approaches could be used to group CFX surfaces for the purpose of applying loads.<br><br>Here¿s one effective albeit somewhat... |
Is the spectrum created by RESP in relative or absolute form? |
A displacement spectrum is relative; an acceleration spectrum is absolute. This has been documented in 12.0 (ref: defect 64267).
|
I have defined a fluid specific source term which includes the specific interfacial area per unit volume. I note that
the documentation says that they are not automatically multiplied by volume fraction. Do I need to multiply my
source term by the fluid volume fraction or not? |
<br><br>Volumetric fluid specific sources are multiplied by the volume of the cell, not by the volume of the phase. As the documentation<br>notes, you¿d have to multiply... |
I used the system kill command to stop a DANSYS job. Can this be restarted? |
Unfortunately, no. If you had terminated it cleanly by creating the jobname.abt file in the working directory with the line TERMINATE, it would have been possible.
|
Why is my large harmonic magnetic analysis aborting? |
This problem may be related to defect 64752, which was related to having a local array that was dynamically allocated on the stack. In ANSYS, we must always allocate memory using the ANSYS heap... |
I am running a transient case and am outputting transient statistics for certain variables.
I know I can get transient averages of parameters such as pressure and density.
Is it possible to get transient averages of pressure or density gradients? (Pressure.Gradient X.trnavg, etc.)? |
You can accomplish this by going through an algebraic variable intermediate.<br><br>For example, for the pressure gradient, you could define a vector<br>algebraic additional... |
I am trying to set the expert parameter 'pt minimum diameter' to eliminate small particles in a particle evaporation model.
Since no units are allowed for this parameter, can you tell me what units this setting refers to? |
<br><br>The default solver units are SI and thus "pt minimum diameter" is assumed to be in [m].<br><br>As units can be set to whatever system is desired in... |
Why is symmetry expansion with /EXPAND not shaded correctly? |
This is defect 65031 and is fixed in 12.0. The element normals in the expanded image were being calculated incorrectly.
|
Why does thermal energy lag electrical energy in a thermal-electric analysis? |
The discrepancy is due to the joule heating being zero at time zero. Electrical energy equation assumes it is constant over the first time step. The effect of this can be reduced by making the... |
Is there a way to "ESORT" shell elements by equivalent stress (SEQV) and then parametrically retrieve the maximum SEQV value? I can sort by centroidal ETABLE value, but that is not necessarily the maximum. I want to retrieve the maximum unaveraged value in the model. |
If you are using full integration (KEYOP(3)=2), the element displays the nodal values of stress with PLESOL,S,EQV, not just a constant centroidal value, so the screen display will contain stress... |
Why are generic ETABLE results (e.g., ETABLE,,S,1) zero if a load case combination is done with SUMTYPE,PRIN? ETABLE items defined with sequence numbers (e.g., ETABLE,,NMISC,31) are not zeroed out. |
This was unintended and has been fixed in ANSYS 12.0.
|
Why is there a low-stress SHELL93 element in the middle of my mixed mesh? |
This is defect 56853 and is fixed in 12.0. The low-stress element was a degenerate element and only three stress values were being passed when 6 were expected by the graphics routine. Using the... |
The only load in my nonlinear analysis is gravity. Why do the reaction forces not match the weight of the structure? |
If you used the STABILIZE command to help obtain convergence, check to see if you used a very short time step. Most of the weight may be carried artificially by the stabilization forces. A second... |
Is the 1-sigma random vibration (PSD) EPELEQV (equivalent strain) computed like the Segalman-Reese SEQV (equivalent stress)? |
No. It is computed on a mode-by-mode basis and is summed directly (similar to how load case combinations are done with SUMTYPE,PRIN), so the value is an upper bound.<br><br>This 1-mode... |
Can a CMS superelement be prestressed? |
Yes. Please see the following example:<br><br><br>fini<br>/clear<br><br>/filnam,part1 ! Name files for part... |
Why do the moments for a BEAM189 model with SECOFFSET seem wrong? |
The redundant axial constraints prevent the beam from compressing or elongating. For a beam with an offset, this prevents rotation, and even though the beam is simply supported, the redundant... |