Chapter 2 Introduction to Workbench and CFX Workflow Introduction to CFX

The Workbench Environment For most situations the Workbench GUI is divided into 2 primary sections (there are other optional sections we’ll see in a moment): The Toolbox The Project Schematic

The Toolbox The toolbox contains 4 subgroups: Analysis systems: Predefined templates that can be placed in the schematic. Component systems: Various applications that can be accessed to build, or expand, analysis systems. Custom Systems: Predefined analysis systems for coupled applications (FSI, thermal-stress, etc.). Users can also create their own predefined systems. Design Exploration: Parametric management and optimization tools.

The Toolbox The systems and components displayed in the toolbox will depend on the installed products. Using the check boxes in the “View All / Customize” window, the items displayed in the toolbox can be toggled on or off. The toolbox customization window is normally left closed when not in use.

The Project Schematic The Workbench project schematic is a graphical representation of the workflow defining a system or group of systems. The workflow in the project schematic is always left to right. There are currently several applications which are native to Workbench, meaning they run entirely in the Workbench window: Project Schematic, Engineering Data and Design Exploration Non-native applications (called data-integrated) run in their own window: Mechanical (formerly Simulation), Mechanical APDL (formerly ANSYS), ANSYS Fluent, ANSYS CFX, Etc . . . Blocks of cells can be deleted by RMB menu selection.

The Project Schematic In this example a Static Structural analysis type is selected for the project schematic. From the toolbox the selection can be dragged and dropped onto the schematic or simply double clicked.

The Project Schematic By dropping applications and/or analyses into various locations in the schematic, an overall analysis project is defined. “Connectors” indicate the level of collaboration between systems. In the example shown a structural system is dragged and dropped onto a thermal system at the Model cell (A4). Before completing the operation notice there are a number of optional “drop” locations that will provide various types of linkage between systems (continued next page).

The Project Schematic By completing the operation from the previous page, notice the linkage here is only at the Model level and above. In this case there would be no thermal/structural coupling. Notice too each system block is given an alphabetic designation (A, B, C, etc.).

The Project Schematic By dropping the structural system at the “Solution” level we obtain a structural system that is coupled to the thermal solution. Notice, the candidate “drop” location indicates data will be shared from fields A2 to A4, and transferred from A6.

The Project Schematic A schematic can also be constructed by RMB and choosing to “Transfer Data To New” or “Transfer Data From New”. In using the RMB transfer feature all transfer possibilities (upstream and downstream) are displayed. These selections will vary depending on which cell in a particular system you highlight.

The Project Schematic Identifying cell states: Unfulfilled: missing upstream data. Attention required: may need to correct this or upstream cells. Refresh required: upstream data has changed. Need to refresh cell. An update will also refresh the cell and regenerate any output data (e.g. mesh, results). Update required: the data has changed and the output of the cell must be regenerated. Up to date. Input changes pending: cell is locally up to date but may change when the next update is performed due to upstream changes. Interrupted: solver was manually stopped before it finished. Can use Resume or Update to continue to solving. Pending: a batch process is in progress

Optional Workbench Windows The “View” menu (and RMB) allows additional information to be displayed in the Workbench environment. Below, the geometry is highlighted and the properties are displayed.

Workbench File Management Workbench creates a project file and a series of subdirectories to manage all associated files. Users should allow Workbench to manage the directories. Please do NOT manually modify the content or structure of the project directories. When a project is saved a project file is created (.wbpj), using the user specified file name (e.g. MyFile.wbpj). A project directory will be created using the project name. In the above example the directory would be MyFile_files. A number of subdirectories will be created in the project directory.

Workbench File Management From the Workbench “View” menu activate the “Files” option to display a window containing file details and locations.

Workbench File Management Archive: quickly generates a single compressed file containing all pertinent files. File is zip format and can be opened using the “Restore Archive . . . ” utility in WB2 or any unzip program. Several options are available when archiving systems as shown here.

Starting CFX CFX can be launched from: The CFX 12.0 Launcher Start > All Programs > ANSYS 12.0 > CFX > ANSYS CFX 12.0 Within ANSYS Workbench Drag ‘Analysis Systems > Fluid Flow (CFX)’ or ‘Component Systems > CFX’ onto the Project Schematic The command line More common under Linux/Unix

Try It Yourself! Now launch Workbench on your training machine… Start > All Programs > ANSYS 12.0 > ANSYS Workbench Expand the Component Systems toolbox and add a CFX system to the Project Schematic Drag a second CFX system onto the Project Schematic, dropping it onto the Solution cell of the first The first Solution is used as the starting point for the second Solution, e.g. a steady-state run followed by a transient run Right-click on the Setup cell in the first system and select Edit This will open CFX-Pre You can leave CFX-Pre open for now

Running Standalone vs Workbench Running CFX inside the Workbench environment: Simplifies the workflow Geometry, Mesh, Setup, Solution and Results steps shown on the Project Schematic Easier to update a project when a change is made E.g. after a geometry change a single click updates the Mesh, Setup, Solution and Results Allows you to easily link to other Analysis Systems and Components Is necessary when performing DesignExploration (parametric studies)

Running Standalone vs Workbench Running CFX standalone: Less computational overhead Produces a simpler directory / file structure on disk But no direct association between geometry, mesh, setup and results files Each component must be updated No built-in automation for parametric studies Less automation E.g mesh needs to be manually imported into CFX-Pre

Setting the Working Directory Before starting a project you should set the working directory Avoids files getting saved to ‘Documents and Settings’ From the CFX Launcher specify the Working Directory before starting Pre / Solver / Post In Workbench Save the project before adding anything to the Project Schematic

Setup / CFX-Pre In WB Edit the Setup entry to start CFX-Pre CFX-Solver CFD-Post In WB Edit the Setup entry to start CFX-Pre Four types of simulation are available General mode is the general purpose mode for defining all types of CFD simulations When running in Workbench CFX-Pre will automatically start in this mode Turbomachinery mode simplifies the setup for rotating machines Quick Setup mode greatly simplifies the physics setup for a simulation by assuming many default parameters and basic physics Library Template mode provides a predefined setup for complex physics Boiling, cavitation, coal & oil combustion, …

CFX-Pre – Workspace CFX-Pre CFX-Solver CFD-Post Main Menu Main Toolbar Viewer Toolbar Outline Tree Viewer Window Message Window

CFX-Pre – Workflow Mesh and region control Import, delete, transform meshes View & edit mesh regions CFX-Pre CFX-Solver CFD-Post Analysis Type Steady State / Transient To define your simulation, generally follow the Outline tree from top to bottom Double-click entries in the Outline tree to edit Right-click on entries in the Outline tree to insert new items or perform operations Some items are optional, depending on your simulation Domain Right-click to insert boundary conditions Boundary Conditions Initialisation Starting point for the solver in the absence of a previous solution Solver settings Convergence controls Results files controls Numerical schemes Monitor points Library objects Optional. Referenced elsewhere in the setup Import Materials & Reactions from libraries provided Insert Expressions, AV’s, Fortran routines

(Hold while tracing a box) Useful Shortcuts Rotate Pan + CTRL Viewer Toolbar Zoom + SHIFT (Hold while tracing a box) Box Zoom Rotate (on screen plane) + CTRL

CFX-Pre – Workflow Example CFX-Solver CFD-Post Load Mesh Right-click on Mesh A Default Domain is automatically created when the mesh is imported. It contains all 3D regions in the mesh. Every domain contains a default boundary condition.

CFX-Pre – Workflow Example Define Domain Properties Right-click on the domain and pick Edit Or right-click on Flow Analysis 1 to insert a new domain CFX-Pre CFX-Solver CFD-Post When editing an item a new tab panel opens containing the properties. You can switch between open tabs. Sub-tabs contain various different properties Complete the required fields on each sub-tab to define the domain Optional fields are activated by enabling a check box

CFX-Pre – Workflow Example Create Boundary Conditions for a Domain Right-click on the domain to insert BC’s CFX-Pre CFX-Solver CFD-Post After completing the boundary condition, it appears in the Outline tree below its domain

CFX-Pre – Workflow Example Define Solver Settings Right-click on Solver Control and pick Edit CFX-Pre CFX-Solver CFD-Post All solver controls have default values

CFX-Pre – Workflow Example Start Solver CFX-Pre CFX-Solver CFD-Post When running in Workbench: Just close CFX-Pre Files are automatically saved Check mark shown next to Setup Right-click on Solution and select Edit or Refresh Refresh runs the solver in the background with default settings Edit opens the Solver Manager When running standalone: You should manually save the CFX-Pre database Right-click on Simulation and select Start Solver > Define Run opens the Solver Manager Run Solver runs in the background with default settings Run Solver and Monitor run with default settings and monitors in the Solver Manager Right-click to solve

CFX-Solver Manager Defining a Run CFX-Pre will have written a .def file and this is automatically selected as the Solver Input File Can enable Initial Values check box if you have a previous solution to use as the starting point Parallel settings are defined here Allows you to divide a large CFD problem so that it can run on more than one processor/machine Start Run! CFX-Pre CFX-Solver CFD-Post

CFX-Solver Manager Workspace CFX-Pre CFX-Solver CFD-Post Create new monitors Solution Monitors Monitor the convergence of the solver Plot residuals, imbalances, monitor points, forces, fluxes… Text output from the Solver Lots of info in here Can also view the .out file in a text editor

CFX-Solver Manager When the Solver finishes, start CFD-Post: CFX-Pre CFX-Solver CFD-Post When running in Workbench: Just close the Solver Manager Check mark shown next to Solution Right-click on Results and select Edit to start CFD-Post When running standalone: Enable Post-Process Results on the solver finished notification window Or select the Post-Process Results icon from the toolbar Right-click to start CFD-Post

CFD-Post Workspace CFX-Pre CFX-Solver CFD-Post Editor Tabs Outline Variables Expressions Calculators Turbo Outline Tree Outline tree displays all post-processing objects. Right-click or double-click to edit in the Details Pane Details Pane Viewer Window

CFD-Post General Workflow Prepare locations where data will be extracted from or plots generated E.g. Planes, Isosurface Create variables/expressions which will be used to extract data (if necessary) E.g. drag, pressure ratio CFX-Pre CFX-Solver CFD-Post i) Generate qualitative data at locations ii) Generate quantitative data at locations Generate Reports

CFD-Post Create Locations Variables / Expressions Qualitative and Quantitative data Reports CFX-Pre CFX-Solver CFD-Post Use the Location drop-down menu in the toolbar to create locations inside the domain 2D & 3D domain, boundary and mesh regions are automatically available Discussed in the Post-processing lecture along with more details on creating locations

Summary of Common File Types .wbpj (Workbench Project File) Import Mesh .cmdb, .cfx5, .def, .res, … Open .cfx, .def, .res CFX-Pre .cfx (CFX-Pre Database) .def (Solver Input or Definition File) CFX-Solver .out (Solver Output File) .res (Results File) .cst (CFD-Post State File) .cse (CFD-Post Session File) .def, .cmdb (Mesh Files) CFD-Post

Summary of Common File Types CFX-Solver CFX-Pre CFD-Post .def (Solver Input or Definition File) .cfx (CFX-Pre Database) .out (Solver Output File) .res (Results File) .cst .cse .def, .cmdb (Mesh Files) Import Mesh .cmdb, .cfx5, .def, .res, … Open .cfx, .def, .res .cfx files contain mesh and physics data and can be opened by CFX-Pre .def files contain mesh and physics data and can be run in the Solver .res files contain mesh, physics and results data and can be opened in CFD-Post CFX-Pre can also open .def and .res files to recover the mesh and physics. Some unused data (e.g. unused Materials) is not written to the .def / .res files and is therefore not recovered. The CFX-Solver can use .res files to continue a run or as an initial guess CFD-Post can also open .def and .cmdb files to view the mesh

Solver Files and Folders C:\Filename.def CFX-Solver C:\Filename_001.out C:\Filename_001 First Time Solving Filename.def C:\Filename_001\100_full.bak C:\Filename_001\1.trn C:\Filename_001\2.trn C:\Filename_001.res C:\Filename.def CFX-Solver C:\Filename_002.out C:\Filename_002 Second Time Solving Filename.def C:\Filename_002\100_full.bak C:\Filename_002\1.trn C:\Filename_002\2.trn C:\Filename_002.res

File Structure in Workbench When running CFX standalone, files are saved to your current working directory As noted on the previous side, some solver files are saved to a solver run directory When running in Workbench only the project file (.wbpj) is saved to the current working directory All other files are saved to a name_files subdirectory C:\StaticMixer.wbpj C:\StaticMixer_files Project files and folders. Do not edit directly

License Preferences Workbench license control is handled through the user interface shown below, activated from the Workbench project page (“Tools > License Preferences . . . “).

License Preferences With the available licenses displayed, the activation and “use order” can be specified using the up/down arrows. 0 = off, 1 = on License order represents the preference order for license use. The license control allows Workbench users to specify whether a single license is used when multiple applications are open, or if all open applications access their own license.

License Preferences In the example shown, a user could have 3 Mechanical models open simultaneously. Using the license control they may choose to open 3 licenses or use only 1 that is shared. In the shared scenario, only the active Mechanical session uses the license (the remaining will be read only).

ANSYS CFX 12.0 Workflow Demo

Workflow Demo Your instructor will now perform a quick demonstration of the workflow in a simple CFX project This simulation sets up the Static Mixer simulation – the first of the tutorials supplied with the ANSYS CFX documentation The mesh for this simulation can be found in the examples directory of your CFX installation and can be imported as a CFX-Solver Input mesh file By default: C:\Program Files\ANSYS Inc\v120\CFX\examples\StaticMixer.def