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<table><tr><td rowspan="2">Identifier</td><td colspan="2">.odb</td><td rowspan="2">Description</td></tr><tr><td>Field</td><td>History</td></tr><tr><td>TURBOMEGA</td><td>●</td><td>●</td><td>Specific turbulent energy dissipation rate.</td></tr><tr><td>TURBNU</td><td>●</td><td>●</td><td>Turbulent eddy viscosity.</td></tr><tr><td colspan="2">TURBVISCOSITYRATIO</td><td>●</td><td>Eddy to molecular viscosity ratio.</td></tr></table>

Nodal variables

You can request nodal variable output to the output database file (see “Node output” in “Output to the output database,” Section 4.1.3).

<table><tr><td>Identifier</td><td>.odbField History</td><td>Description</td></tr><tr><td colspan="3">Geometric quantities</td></tr><tr><td>COORD</td><td>•</td><td>Coordinates of the node. These are the current coordinates if the mesh has moved.</td></tr><tr><td>COORn</td><td>•</td><td>Coordinate n (n = 1, 2, 3).</td></tr><tr><td colspan="3">State and field variables</td></tr><tr><td>DENSITY</td><td>•</td><td>Fluid density at a node.</td></tr><tr><td>DIV</td><td>•</td><td>Divergence of the fluid velocity at a node.</td></tr><tr><td>PRESSURE</td><td>•</td><td>Fluid pressure at a node.</td></tr><tr><td>TEMP</td><td>•</td><td>Fluid temperature at a node.</td></tr><tr><td>U</td><td>•</td><td>Fluid displacement components at a node.</td></tr><tr><td>Un</td><td>•</td><td> $u_n$  fluid displacement component (n = 1, 2, 3).</td></tr><tr><td>V</td><td>•</td><td>Fluid velocity components at a node.</td></tr><tr><td>Vn</td><td>•</td><td> $\dot{u}_n$  fluid velocity component (n = 1, 2, 3).</td></tr><tr><td>QCRIT</td><td>•</td><td>Coherent structure visualizator, known as Qcriteria.</td></tr><tr><td>VGINV2</td><td>•</td><td>Second invariant of the rate-of-strain tensor (symmetric part of the velocity gradient tensor).</td></tr><tr><td>VORTICITY</td><td>•</td><td>Vorticity components at a node.</td></tr><tr><td>VORTICITYn</td><td>•</td><td>Vorticity $_n$  vorticity component (n = 1, 2, 3).</td></tr><tr><td>SHEARRATE</td><td>•</td><td>Shear rate at the nodes computed using the second invariant of the rate-of-strain tensor.</td></tr><tr><td colspan="3">Turbulence variables</td></tr><tr><td>DIST</td><td>•</td><td>Wall-normal distance.</td></tr><tr><td>TURBEPS</td><td>•</td><td>Energy dissipation rate.</td></tr></table>

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<table><tr><td>Identifier</td><td>.odb</td><td>Description</td></tr><tr><td></td><td>Field History</td><td></td></tr><tr><td>TURBKE</td><td>•</td><td>Turbulent kinetic energy.</td></tr><tr><td>TURBOMEGA</td><td>•</td><td>Specific turbulent energy dissipation rate.</td></tr><tr><td>TURBNU</td><td>•</td><td>Turbulent eddy viscosity at a node.</td></tr><tr><td colspan="2">TURBVISCOSITYRATIO</td><td>Eddy to molecular viscosity ratio.</td></tr></table>

# Surface variables

You can request surface variable output to the output database file (see “Surface output in Abaqus/CFD” in “Output to the output database,” Section 4.1.3). The field output corresponds to the element faces attached to a surface.

<table><tr><td>Identifier</td><td>.odbField History</td><td>Description</td></tr><tr><td colspan="3">Geometric quantities</td></tr><tr><td>SURFAREA</td><td>•</td><td>Area of a surface. For deforming meshes, it is the surface area in the current configuration.</td></tr><tr><td colspan="3">State and field variables</td></tr><tr><td>AVGPRESS</td><td>•</td><td>Area-averaged surface pressure.</td></tr><tr><td>AVGTEMP</td><td>•</td><td>Area-averaged surface temperature.</td></tr><tr><td>AVGVEL</td><td>•</td><td>Area-averaged surface velocity vector.</td></tr><tr><td>FORCE</td><td>•</td><td>Total fluid force components on the surface.</td></tr><tr><td>HEATFLOW</td><td>•</td><td>Integrated normal heat flux on a given surface. Heat flow is considered positive if heat is added to the system and negative otherwise. This output request does not include the convective heat flow.</td></tr><tr><td>HFL</td><td>•</td><td>Heat flux vector on a surface. This output request does not include the convective heat flow.</td></tr><tr><td>HFLN</td><td>•</td><td>Normal heat flux on a surface. This output request does not include the convective heat flow.</td></tr><tr><td>MASSFLOW</td><td>•</td><td>Integrated mass flow rate across a given surface.</td></tr><tr><td>NTRACTION</td><td>•</td><td>Fluid normal traction on a surface.</td></tr><tr><td>PRESSFORCE</td><td>•</td><td>Fluid pressure force on a given surface.</td></tr><tr><td>STRACTION</td><td>•</td><td>Fluid surface (or shear) traction on a surface.</td></tr></table>

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<table><tr><td rowspan="2">Identifier</td><td colspan="2">.odb</td><td rowspan="2">Description</td></tr><tr><td>Field</td><td>History</td></tr><tr><td>TRACTION</td><td>•</td><td></td><td>Fluid total traction on a surface. This is equal to the sum of the normal traction (NTRACTION) and the shear traction (STRACTION).</td></tr><tr><td>VISCFORCE</td><td></td><td>•</td><td>Fluid viscous force on a given surface.</td></tr><tr><td>VOLFLOW</td><td></td><td>•</td><td>Integrated volume flow rate across a given surface.</td></tr><tr><td>WALLSHEAR</td><td>•</td><td></td><td>Fluid shear stress magnitude on a surface. It is the magnitude of the shear traction (STRACTION) vector.</td></tr><tr><td colspan="4">Turbulence variables</td></tr><tr><td>YPLUS</td><td>•</td><td></td><td>Wall-normal distance measured in viscous lengths or wall units. A default value of 0 is output for surfaces that are not attached to a wall boundary.</td></tr><tr><td>YSTAR</td><td>•</td><td></td><td>Wall-normal distance scaled using turbulent kinetic energy and viscosity. YSTAR output is available only when a turbulence model is specified. A default value of 0 is output for surfaces that are not attached to a wall boundary.</td></tr></table>

Whole and partial model variables

The output variables listed below are available for part of the model as well as the whole model.

<table><tr><td>Identifier</td><td>.odbField History</td><td>Description</td></tr><tr><td colspan="3">Geometric quantities</td></tr><tr><td>VOL</td><td>•</td><td>Current volume of the entire set or the entire model.</td></tr></table>

# Total energy output quantities

If the following whole model variables are relevant for a particular analysis, you can request them as output to the output database file (see “Total energy output” in “Output to the output database,” Section 4.1.3). If you do not specify an output region, whole model variables are calculated. When you specify an output region, the relevant energy totals are calculated over the user-specified region.

ALLKE Kinetic energy.

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# 4.3 The postprocessing calculator

• “The postprocessing calculator,” Section 4.3.1

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# 4.3.1 THE POSTPROCESSING CALCULATOR

Products: Abaqus/Standard Abaqus/Explicit

# References

• “Output to the output database,” Section 4.1.3   
• “Abaqus/Standard output variable identifiers,” Section 4.2.1   
• “Abaqus/Explicit output variable identifiers,” Section 4.2.2   
• “Abaqus/Standard, Abaqus/Explicit, and Abaqus/CFD execution,” Section 3.2.2

# Overview

The postprocessing calculator can perform operations on output quantities written to the output database (job-name.odb) by Abaqus. It then expands the output database by writing these new output quantities to the output database. Once this expansion is done, it is not possible to convert the output database back to its original form. The postprocessing calculator is for use only with the Visualization module of Abaqus/CAE (Abaqus/Viewer).

# Functionality of the calculator

The postprocessing calculator performs the following calculations on data written to the output database:

• Extrapolation of integration point quantities to the nodes or interpolation of integration point quantities to the centroid of an element, according to the user-specified position for element output; see “Selecting the position of element integration point and section point output” in “Output to the output database,” Section 4.1.3, for details.   
• Calculation of history output at tracer particles; see “Tracer particle output from Abaqus/Explicit” in “Output to the output database,” Section 4.1.3.

# Running the calculator

The postprocessing calculator is generally not required in Abaqus/Standard because by default Abaqus/Standard performs results postprocessing during the course of the analysis. You can override this default behavior by using the environment variable auto\_calculate in the Abaqus environment file. See “Using the Abaqus environment settings,” Section 3.3.1, for details.

By default in Abaqus/Explicit or if requested in Abaqus/Standard (using auto\_calculate in the Abaqus environment file), the postprocessing calculator will run automatically upon the completion of an analysis. During the execution of the analysis, Abaqus will determine if there are keywords in the input file that require the use of the calculator and will initiate the calculator upon completion if it is required. You can override this default behavior by using the environment variable auto\_calculate in the Abaqus environment file. See “Using the Abaqus environment settings,” Section 3.3.1, for details.

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You can run the postprocessing calculator manually by using the convert=odb option on the abaqus execution procedure.

To see the postprocessed results before an analysis is complete, you can run the postprocessing calculator manually while the analysis is still running, using the oldjob option in conjunction with the convert=odb option on the abaqus execution procedure. The postprocessing calculator will write a new output database using the value of the job parameter as the file name. Due to the fact that the analysis is writing to the output database at the same time the postprocessing calculator is attempting to read it, the output database may be in an inconsistent state that makes reading it impossible. If this problem occurs, the postprocessing calculator will stop attempting to read the output database and exit. A warning message explaining what has happened will be output to the screen. You can then attempt to run the postprocessing calculator again. If the inconsistent state has cleared, the postprocessing calculator will run normally.

If the postprocessing calculator is run during an analysis without the oldjob option, Abaqus will ask you to confirm that the existing output database can be overwritten. You should make sure the analysis is complete before running the postprocessing calculator manually without the oldjob option. If the analysis is still running when the postprocessing calculator is run without using the oldjob option, the output database will be corrupted.

For a detailed description of the procedure for running the postprocessing calculator manually, see “Abaqus/Standard, Abaqus/Explicit, and Abaqus/CFD execution,” Section 3.2.2.

If an analysis aborts because available CPU time has expired and you restart the analysis, the postprocessing calculator will not automatically expand the output database from the original, aborted run. You must manually run the postprocessing calculator to expand the original output database using the procedure outlined above.

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# 5. File Output Format

Accessing the results file

5.1

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