Cart3D使用教程.doc

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1、Cart3D使用教程（OverviewThis tutorial illustrates how to generate a grid in Cart3D around a set of three plugs.This tutorial introduces the following operations:1. Use of the Cart3D mesher for mesh generation.2. Multigrid preparation running mgPrep.The input files for this tutorial can be found in the An

2、sys Installation directory, under ./docu/Tutorials/CFD_Tutorial_Files/Cart3D_Examples. Copy and open the plugs.uns file in your working directory.Note: It is preferable to create a separate folder plugs and put only the plugs.uns (domain/mesh) file in that folder before performing this tutorial.Sele

3、ct Open Mesh from the main menu and select plugs.uns. The model contains three closed triangulated components. Press the h key to fit the view in the screen if the model is not visible.Click on the Cart 3D tab. Select the Volume Mesher icon . The following window will open.Toggle ON Fix Normals-it w

4、ill fix the orientation of the triangles such that their normals point outwards.Choose Nominal Mesh Radius (Body Length X)=20, Starting Mesh Divisions = 5 5 5 and Max Num of Cell Refinements = 11.Press Compute Parameters button. This saves the mesh in the local directory, converts in into Cart3D for

5、mat, and determines the intersections if any. This step is required even if there is only one component - to convert the triangulation to Cart3D tri format. At the end, it displays the Finest Cell Dimension as shown below.Figure 3-482 Cart3D Mesher windowThis will create 4 density polygons for mesh

6、density control, which can be viewed in the Display Tree by switching on the Geometry Densities.This also computes the finest cell size: 0.983 x 0.983 x 0.983. Varying the starting mesh division and/or Max number of cell refinements can vary the finest cell size.The diagonal points displayed under t

7、he Outer Bounding Box are the Minimum and Maximum points of the bounding box/Mesh region. They can be changed if desired.Set the Angle Threshold for Refinement to 5 as shown in below.Figure 3-483 Change Angle of RefinementClick Apply to run the mesher. This will create a domain file with 3 Cut Plane

8、s (Quad Elements) in each coordinate direction and Cut Cells (Hex Elements) through which the defining surface triangles pass. This Preview Mesh will be loaded automatically. In the Part Menu under the Display Tree right-click on Parts and select Hide All. Then turn on only the Part CUTPLANE-Z2.Figu

9、re 3-484 Display TreeThe mesh is shown here. This is the projected mesh on the middle plane in the Z-direction CUTPLANE-Z2.Figure 3-485 Cut Plane Z2 MeshRight-click in the Display Tree and select Parts Show All after viewing the mesh.Now in the Cart3D Mesher window enable Create and Save Full Mesh a

10、s shown.Figure 3-486 Create and Save Full MeshLeave the Number of Multi grid levels to 5. This will create 5 levels of coarsened mesh, which can be read by the solver.Press Apply. The Cart3D Mesh window appears which asks us about loading the cart3D full mesh, press Yes.Figure 3-487 Cart3D Mesh wind

11、owSwitch on Mesh Volumes in the Display Tree.The final mesh generated can be examined through Mesh Cut plane. The Define Cut Planes window appears as shown. Accept the default settings.Figure 3-488 Cut Plane DisplayThe mesh viewed using the above parameters is shown below.Figure 3-489 Cut Plane mesh

12、Tutorial Onera M6 Wing with 0.54 M Home CAE Index ANSYS Index Overview This tutorial illustrates how to generate a grid in Cart3D around a Wing and how to solve the problem in flowCart. Post-processing the results is also explained.This tutorial introduces the following operations:1. Use of the Cart

13、3D mesher for mesh generation2. Multi grid preparation with mgPrep3. Running the solver for AOA=3.06 and Mach=0.544. Computing Forces and Moments using Clic.5. Visualizing the result in Post ProcessingThe input files for this tutorial can be found in the Ansys Installation directory, under ./docu/Tu

14、torials/CFD_Tutorial_Files/Cart3D_Examples. Note: It is preferable to create a separate folder wing1 and put the oneraM6.uns (domain) file in that folder before performing this tutorial.Select Open Mesh from the main menu and select oneraM6.uns.Click on Cart3D from the main menu. Select the Volume M

15、esher icon. We get the cart 3D Mesher window as shown below.Figure 3-490Cart3D GUI windowToggle ON- Fix Normals. This will fix the orientation of the triangles such that their normals are pointing outward.Choose Nominal Mesh Radius (Body Length X) = 20, Starting Mesh Divisions = 3 3 3 and Max number

16、 of Cell Refinements = 12 .Click Compute Parameters. This saves the mesh in the local directory, converts in into Cart3D format, and finds the intersections if any. This is required to convert the triangulation to Cart3D tri format even if there is only one component present. At the end, it displays

17、 the Finest Cell Dimensions as shown.Figure 3-491 Cart3D Mesher windowThis will create 2 density polygons for mesh density control that can be seen by activating GeometriesDensities in the Display Tree.This also computes the Finest Cell Dimensions: 0.00737 x 0.00737 x 0.00737. Varying the Starting M

18、esh Divisions and/or Max Num of Cell Refinements can vary these values. The diagonal points displayed under the Outer Bonding Box are the maximum and minimum points of the bounding box of the Mesh region. They can be changed if desired. Set the Angle Threshold for Refinement to 5Note: In this case w

19、e wish to run the case with symmetry in the Z direction. Specify the bounding box minimum Z coordinate as 0.00001 (slightly inside the model). If the model itself is symmetric, turn on Half-Body Mesh (Symmetric in Z).Click Apply (after specifying minimum Z coordinates as 0.00001) as shown below to r

20、un the mesher. This will create a domain file with 3 Cut Planes (Quad Elements) in each coordinate direction and Cut Cells (Hex Elements). The Preview Mesh will be loaded automatically.Figure 3-492Change Angle of RefinementIn the Parts menu under the Display Tree perform the operation PartsHide All

21、(right-click on Parts to access) and then turn on only the Part CUTPLANE-Z2.Figure 3-493Display Tree The mesh projected onto the middle z-direction plane (in Part CUTPLANE-Z2) is shown below.Figure 3-494 CUTPLANE-Z2 MeshPerform the operation Parts Show All by a right-click on Parts in the Display Tr

22、ee after viewing the meshIn the Cart3D Menu select Solver . Click on Define Solver params icon (if the panel doesnt open automatically). A Solver parameters window appears as shown.Figure 3-499 Solver parameters windowSet File InformationMesh File as WING1_c3d.mesh.mg (should be default).Click on Ca

23、se Information and enter the following parameters:Mach number = 0.54Angle of Attack = 3.06Side Slip angle = 0.0Specific Heat Ratio = 1.4Free Stream Density = 1.0Figure 3-500 Case Information windowExpand Solver Controls Runge-Kutta Scheme in the Display Tree as shown and accept the default settings.

24、Figure 3-501 Runge-Kutta Scheme windowIn Other controls specify the following parameter values:CFL number: 1.4Limiter Type: van leerFlux function: van LeerCut-Cell BCtype: Agglomerated NormalsNumber of Multi-Grid levels: 3MultiGrid cycle type: W-cycleNumber of pre-smoothing passes:1Number of post-sm

25、oothing passes:1Figure 3-502Other controls windowKeep defaults for Boundary Conditions, Convergence History, and Partition Information and press Accept.Select Solver Run Solver to open the flow chart solver panel.Specify Max. Number of Cycles = 150.Turn on Save Full Hex Result.Turn on Save Cut plane

26、s result and specify Z-Slices as 0.001 0.297 0.653 0.965 1.187 1.3336 and 1.410.Click Apply to run the solver.Figure 3-503 Run Solver windowThe user can view the convergence by selecting the Convergence monitor icon as shown. (The monitor may open automatically.)Figure 3-504 Solution Convergence Win

27、dowIn the Cart3D main menu select Integrate Cp . The Post-Process Solution window will appear.Figure 3-505 Post-Process Solution windowClick All Params in the Post-Process Solution window.In the Reference All Params window specify Reference Area as 1.1589, Reference Length as 1Enable Compute Force a

28、nd Compute Moment.Set Moment about Point = 0.5 0 0, Point1 = 0.5 0 0, and Point2 = 1.125 0 1.Click Apply in the Reference All Params window and then Dismiss to close.Figure 3-506 Reference All Params WindowPress Apply in the Post-Process Solution window. The results appear in the GUI messages area.V

29、isualizing the results FlowCart writes three output files:-i)WING1_c3d.i.triq - Contains Pressure, Velocity and Density extrapolated to the Surface triangles. This can be converted to a domain file by EditCart3D Tri File-Domain file. The default resultant domain file will be WING1_c3d.uns.ii) sliceP

30、lanes.dom - Cut Plane results.iii) results.dom - Full mesh results.Go to File Results Open Results.Select Format as ICEM CFD.Specify surface_results.dom as the File.Figure 3-507Select Result File WindowSelect Apply from the panel to get the default result as shown. Right click on Colormap from the D

31、isplay Tree and select Modify Entries to adjust the Min and Max values for the displayed variable.Figure 3-508 Visualization of ResultsThe input files for this tutorial can be found in the Ansys Installation directory, under ./docu/Tutorials/CFD_Tutorial_Files/Cart3D_Examples. Note: It is preferable

32、 to create a separate folder wing1 and put the oneraM6.uns (domain) file in that folder before performing this tutorial.Select Open Mesh from the main menu and select oneraM6.uns.Click on Cart3D from the main menu. Select the Volume Mesher icon. We get the cart 3D Mesher window as shown below.Figure

33、 3-509 Cart 3D Mesher windowToggle ON Fix Normals. This will fix the orientation of the triangles such that their normals are pointing outward.Choose Nominal Mesh Radius (Body Length X) = 20, Starting Mesh Divisions = 3 3 3 and Max number of Cell Refinements = 12 .Click Compute Parameters. This save

34、s the mesh in the local directory, converts in into Cart3D format, and finds the intersections if any. This is required to convert the triangulation to Cart3D tri format even if there is only one component present. At the end, it displays the Finest Cell Dimensions as shown.Figure 3-510Cart3D Mesher

35、 windowThis will create 2 density polygons for mesh density control that can be seen by activating GeometriesDensities in the Display Tree.This also computes the Finest Cell Dimensions: 0.00737 x 0.00737 x 0.00737. Varying the Starting Mesh Divisions and/or Max Num of Cell Refinements can vary these

36、 values. The diagonal points displayed under the Outer Bonding Box are the maximum and minimum points of the bounding box of the Mesh region. They can be changed if desired. Set the Angle Threshold for Refinement to 5Note: In this case we wish to run the case with symmetry in the Z direction. Specif

37、y the bounding box minimum Z coordinate as 0.00001 (slightly inside the model). If the model itself is symmetric, turn on Half-Body Mesh (Symmetric in Z).Click Apply (after specifying minimum Z coordinates as 0.00001) as shown to run the mesher. This will create a domain file with 3 Cut Planes (Quad

38、 Elements) in each coordinate direction and Cut Cells (Hex Elements). The Preview Mesh will be loaded automatically.Figure 3-511 Change Angle of RefinementIn the Parts menu under the Display Tree perform the operation Parts Hide All (right-click on Parts to access) and then turn on only the Part CUT

39、PLANE-Z2.Figure 3-512 Display TreeThe mesh projected onto the middle z-direction plane (in Part CUTPLANE-Z2) is shown below.Figure 3-513 CUTPLANE-Z2 MeshPerform the operation Parts Show All by a right-click on Parts in the Display Tree after viewing the mesh.Now in the Cart3D mesher window enable Cr

40、eate and Save Full Mesh. Set the Number of Multi grid levels to 3. This will create 3 levels of coarsened mesh, which can be read by the solver.Figure 3-514 Create and Save Full MeshPress Apply. The Cart3D Mesh window appears which asks about loading the Cart3D Full Mesh as shown. Press Yes.Figure 3

41、-515Cart3D Mesh windowThe final mesh generated can be examined through Mesh Cutplane. The Define Cut Planes window appears as shown. Accept the default settings.Figure 3-516 Define Cut Planes WindowThe mesh cut plane using the above parameters is shown below.Figure 3-517 Cut Plane Mesh1 In the Cart3

42、D Menu select Solver . Click on Define Solver params icon (if the panel doesnt open automatically). A Solver parameters window appears as shown.Figure 3-518 Solver parameters windowSet File Information Mesh File as WING2_c3d.mesh.mg (should be default).Click on Case Information window and enter the

43、following parametersMach Number = 0.84Angle of Attack = 3.06Side Slip angle = 0.0Specific Heat Ratio = 1.0Free Stream Density = 1.0Figure 3-519 Case Information windowExpand Solver Controls Runge-Kutta Scheme in the Display Tree as shown and accept the default settings.Figure 3-520 Runge-Kutta Schem

44、e window5. In Other controls specify the following parameter values:CFL number: 1.4Limiter Type: van LeerFlux function: van LeerCut-Cell BCtype: Agglomerated NormalsNumber of Multi-Grid levels 3MultiGrid cycletype W-cycleNumber of pre-smoothing passes 1Number of post-smoothing passes 1Figure 3-521Ot

45、her Control windowKeep defaults for Boundary Conditions, Convergence History, and Partition Information and press Accept.Select Solver Run Solver to open the flow chart solver panel. Specify Max. Number of Cycle=150. Turn on Save Full Hexa Result.Turn on Save Cut planes result and specify Z-Slices a

46、s 0.001 0.297 0.653 0.965 1.187 1.3336 and 1.410. Click Apply and run the solver.Figure 3-522 Run Solver window6. The user can view the convergence via the Convergence Monitor icon . (The monitor may open automatically.)Figure 3-523 Solution Convergence Window Flow charts write three output files:i) WI