Simulation > > ANSYS WB - Supersonic Flow Over a Wedge - Problem SpecificationLabels: NoneSimCafeHome Browse/Manage LoginSearchANSYS WB - Supersonic Flow Over a Wedge - Problem SpecificationAdded by Benjamin J Mullen , last edited by Benjamin J Mullen on Mar 01, 2012 18:19 Author: Benjamin Mullen, Cornell UniversityProblem Specification1. Pre-Analysis & Start-Up2. Geometry3. Mesh4. Setup (Physics)5. Solution6. Results7. Verification & Validation8. ExercisesA uniform supersonic stream encounters a wedge with a half-angle of 15 degrees as shown in the figure below.The stream is at the following conditions:Using FLUENT, calculate the Mach Number, static and total pressure behind the oblique shock that will be formed. Also, calculate theshock angle, pressure coefficient along the wedge and drag coefficient. Compare the FLUENT results with the correspondinganalytical results.Go to Step 1 - Pre-Analysis & Start-UpThis work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States LicenseAdaptavist Theme Builder (4.2.4-M1) Powered by Atlassian Confluence 3.5.16, the Enterprise WikiSearch CornellANSYS WB - Supersonic Flow Over a Wedge - Problem Specification - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Problem+Specification 1 / 28Simulation > > ANSYS WB - Supersonic Flow Over a Wedge - Pre-Analysis & Start-UpLabels: NoneSimCafeHome Browse/Manage LoginSearchANSYS WB - Supersonic Flow Over a Wedge - Pre-Analysis & Start-UpAdded by Benjamin J Mullen , last edited by Benjamin J Mullen on Mar 02, 2012 10:39 Author: Benjamin Mullen, Cornell UniversityProblem Specification1. Pre-Analysis & Start-Up2. Geometry3. Mesh4. Setup (Physics)5. Solution6. Results7. Verification & Validation8. ExercisesPre-Analysis & Start-UpPre-AnalysisIn order to calculate the expected results behind the shock, we recommend using a oblique shock wave calculator (link grc.nasa.gov).At Mach 3 and an angle of 15 degrees, we find the following:Open ANSYS WorkbenchWe are ready to do a simulation in ANSYS Workbench! Open ANSYS Workbench by going to Start > ANSYS > Workbench. This willopen the start up screen seen as seen belowSearch CornellANSYS WB - Supersonic Flow Over a Wedge - Pre-Analysis & Start-Up - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/pages/viewpage.action?pageId=170201582 2 / 28Screen ManagementThis tutorial is designed such that the user can have both ANSYS Workbench and the tutorial open. As shown below, this onlinetutorial should fill approximately 1/3 of the screen, while ANSYS Workbench fills the remaining 2/3 of the screen.Setup ProjectTo begin, we need to tell ANSYS what kind of simulation we are doing. If you look to the left of the start up window, you will see theToolbox Window. Take a look through the different selections. We will be using FLUENT to complete the simulation. Load the F l u i dF l o w ( F L U E N T ) box by dragging and dropping it into the Project Schematic. Right click the top box of the project schematic and go to R e n a m e , and name the project SupersonicFlow Over a Wedge.You are ready to create the geometry for the simulation.Go to Step 2 - GeometryThis work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States LicenseAdaptavist Theme Builder (4.2.4-M1) Powered by Atlassian Confluence 3.5.16, the Enterprise WikiANSYS WB - Supersonic Flow Over a Wedge - Pre-Analysis & Start-Up - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/pages/viewpage.action?pageId=170201582 3 / 28Simulation > > ANSYS WB - Supersonic Flow Over a Wedge - GeometryLabels: NoneSimCafeHome Browse/Manage LoginSearchANSYS WB - Supersonic Flow Over a Wedge - GeometryAdded by Benjamin J Mullen , last edited by Benjamin J Mullen on Mar 04, 2012 12:09 Author: Benjamin Mullen, Cornell UniversityProblem Specification1. Pre-Analysis & Start-Up2. Geometry3. Mesh4. Setup (Physics)5. Solution6. Results7. Verification & Validation8. ExercisesGeometryCare to skip the geometry and meshing steps? READMEIf you would prefer to skip the geometry and mesh steps, then you can download the necessary files here. Downloadthe "zip" file, then extract the files to your working directory. In order to load the necessary files, go to theW o r k b e n c h P r o j e c t P a g e , then ( C l i c k ) F i l e > O p e n > " S u p e r s o n i c F l o w O v e r W e d g e . w b p j " . Lastly,click here to skip ahead to Step 4 of the tutorial.Set UpFirst, we need to specify that the geometry is 2-dimensional. Right click the Geometry box and select P r o p e r t i e s .This will open the P r o p e r t i e s o f S c h e ma t i c A 2 : Ge o me t r y Window. Under A d v a n c e Ge o me t r y Op t i o n s change A n a l y s i sT y p e from 3 Dto 2 D.Search CornellANSYS WB - Supersonic Flow Over a Wedge - Geometry - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Geometry 4 / 28After the analysis type has been set, we are ready to launch Design Modeler, the geometry engine in ANSYS. Open Design Modelerby double clicking the geometry box. After launching Design Modeler, you will be prompted to choose standard units.Select M e t e r as the standard unit, and click O K.SketchingWe want to sketch on the XY plane. To look at the XY plane, click the positive Z-Axis on the compass in the Gr a p h i c s window.To begin sketching, click on the S k e t c h i n g tab in the Tr e e Ou t l i n e window. To draw our domain, we will use the Rectangle tool.Click on in the S k e t c h i n g To o l b o x e s window. In the graphics window, draw the rectangle by first clicking on the origin(make sure the P icon is showing, meaning you are in fact selecting the point), then select a point in the 1st quadrant.Now, we need to draw the wedge outline in the geometry. We will use the line tool to create the wedge. Select the line tool in theANSYS WB - Supersonic Flow Over a Wedge - Geometry - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Geometry 5 / 28S k e t c h i n g To o l b o x e s window. Click on the points shown in the below figure. Make sure the "C" is showing.Now, we need to remove the extraneous lines that we created. In the S k e t c h i n g To o l b o x e s window, click the M o d i f y tab, andselect. Next, trim the lines indicated by the figure belowThe final sketch should look like the image belowDimensionsNext, we need to add the dimensions for the geometry. In the S k e t c h i n g To o l b o x e s window, select the D i m e n s i o n s tab. Next,select the general dimensioning tool. To create a dimension, you first select a line. This will create a dimension for that line.Next, you will need to place the dimension next to the line. See the image below for guidance.Next, create dimensions for the following 4 lines:ANSYS WB - Supersonic Flow Over a Wedge - Geometry - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Geometry 6 / 28In order to add magnitudes to the dimensions, look to the D e t a i l s window. You will see 4 dimensions that have been specified. Clickon a dimension magnitude, and notice that the corresponding dimension will be highlighted in the graphics window. Use the followingdiagram to add the dimensions to the geometry.When the dimensions have been correctly applied, the geometry should look like this:Create SurfaceNext, we need to create a surface from the sketch. In the menu tool bar, select Concept > Surface from Sketches. In the graphicswindow, select any line of the geometry.Next, in the details window, select B a s e O b j e c t s > A p p l y . Finally, press. The geometry should now look like the figurebelow.Create a projectionANSYS WB - Supersonic Flow Over a Wedge - Geometry - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Geometry 7 / 28Now, we want to project the center vertical line onto the surface body we just created. This will help us with our mesh. In the menu bar,select N e w S k e t c h icon to create a new sketchThis will create a new sketch. In the Ou t l i n e window, return to the S k e t c h i n g tab. Again, select the tool. Draw a line fromthe vertex of the wedge to the top of the geometry. Make sure that when you click a vertex, a "P" appears (meaning point, constrainingthe line to the vertex), a "V" appears on the line (meaning vertical, putting a vertical constraint on the line), and a "C" appears whenyou click on the top line (constraining the newly created line to the top line). Right before you make your second click to define the line,make sure it looks like this:The line will turn dark blue if you have done this correctly (meaning the line is fully constrained) Now, we need to create a line bodyfrom this sketch. In the menu bar, go to L i n e s f r o m S k e t c h e s . In the graphics window, select the line you just drew. In the Ou t l i n ewindow, select B a s e O b j e c t s > A p p l y . Finally, press.Finally, we are ready to project the line on the surface. In the menu bar, go to Tools > Projection. First, you will need to select anedge. Select the middle vertical line we just created. In the d e t a i l s window, select E d g e s > A p p l yNext, we need to select the surface body for the projection. In the D e t a i l s window, select T a r g e t , then select any point on thesurface body.In D e t a i l s window, select T a r g e t > A p p l y . Finally, press. The line should now be projected on the surface. Now that wehave the surface and the projection, we no longer need the line body we first created. In the Ou t l i n e window, Expand 2 P a r t s , 2B o d i e s . Right click L i n e B o d y and select S u p p r e s s B o d yANSYS WB - Supersonic Flow Over a Wedge - Geometry - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Geometry 8 / 28Now that we have completed the geometry. Save the project, and close the Design Modeler.Go to Step 3 - MeshThis work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States LicenseAdaptavist Theme Builder (4.2.4-M1) Powered by Atlassian Confluence 3.5.16, the Enterprise WikiANSYS WB - Supersonic Flow Over a Wedge - Geometry - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Geometry 9 / 28Simulation > > ANSYS WB - Supersonic Flow Over a Wedge - MeshLabels: NoneSimCafeHome Browse/Manage LoginSearchANSYS WB - Supersonic Flow Over a Wedge - MeshAdded by Benjamin J Mullen , last edited by Benjamin J Mullen on Mar 01, 2012 23:13 Author: Benjamin Mullen, Cornell UniversityProblem Specification1. Pre-Analysis & Start-Up2. Geometry3. Mesh4. Setup (Physics)5. Solution6. Results7. Verification & Validation8. ExercisesMeshLaunch the MesherNow that we have completed creating the geometry of the domain, we are ready to mesh it. Return to the P r o j e c t S c h e ma t i cWindow. In the P r o j e c t S c h e ma t i c window, double click the Mesh box to launch the mesher.Mapped Face MeshingFirst we will apply a mapped face meshing; this will give us a regular mesh. First, in the Ou t l i n e window, click to show theMesh menu in the menu bar. In the Meshing Menu, select Mesh Control > Mapped Face Meshing. In the Gr a p h i c s window, holddown CRTL, and select b o t h domain faces to select it, then in the D e t a i l s window, click G e o m e t r y > A p p l y .Body SizingNext, we will create a body sizing for the elements that will make up the domain. In the Mesh Menu, select Mesh Control > Sizing.Next, select the body selection filter in the menu barNext, select the surface in the graphics window. In the D e t a i l s window, select G e o m e t r y > A p p l y . Now, we want to change theelement size. In the D e t a i l s Wi n d o w , select E l e m e n t S i z e > D e f a u l t and change the value to 0 . 0 5 m .Search CornellANSYS WB - Supersonic Flow Over a Wedge - Mesh - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Mesh 10 / 28Generate the MeshNow, we are ready to generate the mesh. Generate the mesh by clicking in the menu bar or by going to Mesh >Generate Mesh. The final mesh should resemble the one in the figure below.Named SelectionsNow, we need to create named selections to use when we set boundary conditions. To create a named selection, first ensure that theedge selection filter is selected. Next, left click on the desired edge you wish to name (multiple edges can be selected whileholding down CTRL), then right click on the edge and select C r e a t e N a m e d S e l e c t i o n .Once you select C r e a t e N a m e d S e l e c t i o n , a dialogue box will appear where you will enter the desired name of the boundary.Use the diagram below to name all of the boundaries of the geometry.There are 4 edges that make up the farfield, and they can all be named at once by holding down CTRL, left clicking allof the edges while holding down CTRL, then right clicking and selecting "Create Named Selection"ANSYS WB - Supersonic Flow Over a Wedge - Mesh - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Mesh 11 / 28Once the selections are all named and the mesh is created, you may save the project and close the mesher.Go to Step 4 - Setup (Physics)This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States LicenseAdaptavist Theme Builder (4.2.4-M1) Powered by Atlassian Confluence 3.5.16, the Enterprise WikiANSYS WB - Supersonic Flow Over a Wedge - Mesh - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Mesh 12 / 28Simulation > > ANSYS WB - Supersonic Flow Over a Wedge - Setup (Physics)Labels: NoneSimCafeHome Browse/Manage LoginSearchANSYS WB - Supersonic Flow Over a Wedge - Setup (Physics)Added by Benjamin J Mullen , last edited by Benjamin J Mullen on Mar 01, 2012 23:16 Author: Benjamin Mullen, Cornell UniversityProblem Specification1. Pre-Analysis & Start-Up2. Geometry3. Mesh4. Setup (Physics)5. Solution6. Results7. Verification & Validation8. ExercisesSetup (Physics)Update the Project and Open FLUENTBefore we open FLUENT, we need to update the project the import the mesh into FLUENT. To do this, click Update Project . When the project updates, double click Setup to open FLUENT.Initial SettingsBefore FLUENT launches, we will be prompted to set some options. In Op t i o n s check the box next to D o u b l e P r e c i s i o n . If youhave a dual processor, you can set the option under P r o c e s s i n g Op t i o n s to P a r a l l e l , and change the N u m b e r o f P r o c e s s e sto 2. We don't necessarily need the parallel processes for this simulation as it is fairly simple, but it becomes necessary later whenwe refine the mesh and complicate the simulation further by changing boundary conditions. Once the options are set, click OK.Search CornellANSYS WB - Supersonic Flow Over a Wedge - Setup (Physics) - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Setup+%28Physics%29 13 / 28Problem Setup - GeneralNow, FLUENT should open. We will begin setting up some options for the solver. In the left hand window (in what I will call theOu t l i n e window), under P r o b l e m S e t u p , select G e n e r a l . The only option we need to change here is the type of solver. In theS o l v e r window, select D e n s i t y - B a s e d .ModelsIn the outline window, click M o d e l s . We will need to utilize the energy equation in order to solve this simulation. Under Mo d e l shighlight E n e r g y - O f f and click E d i t . . . . Now, the E n e r g y window will launch. Check the box next to E n e r g y E q u a t i o n and hitOK. We also need to change the type of viscosity model. Select V i s c o u s - L a m i n a r and click E d i t . . . . Choose the I n v i s c i doption and press O K.MaterialsIn the Ou t l i n e window, highlight M a t e r i a l s . In the Ma t e r i a l s window, highlight F l u i d , and click C r e a t e / E d i t . . . . this will launch theC r e a t e / E d i t Ma t e r i a l s window; here we can specify the properties of the fluid. Set the D e n s i t y to I d e a l G a s , the S p e c i f i cH e a t to 1006.43, the M o l e c u l a r W e i g h t to 28.966. When you have updated these fields, press C h a n g e / C r e a t e .Boundary ConditionsIn the Ou t l i n e window, select B o u n d a r y C o n d i t i o n s . We will now specify each boundary condition for the simulation.FarfieldIn the B o u n d a r y C o n d i t i o n s window, select f a r f i e l d . Use the drop-down menu to change the T y p e to p r e s s u r e - f a r - f i e l d . Youwill be asked to confirm the change, and do so by pressing O K. Next, a dialogue box will open with some parameters we need tospecify. Change the G a u g e P r e s s u r e ( P a s c a l ) to 1 0 1 3 2 5 , and M a c h N u m b e r to 3.ANSYS WB - Supersonic Flow Over a Wedge - Setup (Physics) - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Setup+%28Physics%29 14 / 28Also, select the T h e r m a l tab, and ensure that the temperature correctly defaulted to 3 0 0 K . When you are finished, press O K.WedgeIn the B o u n d a r y C o n d i t i o n s window, select w e d g e . Use the drop-down menu to change the T y p e to w a l l .SymmetryIn the B o u n d a r y C o n d i t i o n s window, select s y m m e t r y . Use the drop-down menu to change the T y p e to s y m m e t r y .Operating ConditionsIn the B o u n d a r y C o n d i t i o n s window, select the O p e r a t i n g C o n d i t i o n s button. Change the G a u g e P r e s s u r e to 0. Thenpress O KReference ValuesIn the Ou t l i n e window, select R e f e r e n c e V a l u e s . Change the C o m p u t e F r o m parameter to f a r f i e l d . Check that the valuesare accurate. The reference values are used when calculating the non-dimensional results such as the drag coefficient.Go to Step 5 - SolutionANSYS WB - Supersonic Flow Over a Wedge - Setup (Physics) - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Setup+%28Physics%29 15 / 28This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States LicenseAdaptavist Theme Builder (4.2.4-M1) Powered by Atlassian Confluence 3.5.16, the Enterprise WikiANSYS WB - Supersonic Flow Over a Wedge - Setup (Physics) - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Setup+%28Physics%29 16 / 28Simulation > > ANSYS WB - Supersonic Flow Over a Wedge - SolutionLabels: NoneSimCafeHome Browse/Manage LoginSearchANSYS WB - Supersonic Flow Over a Wedge - SolutionAdded by Benjamin J Mullen , last edited by Benjamin J Mullen on Mar 01, 2012 23:16 Author: Benjamin Mullen, Cornell UniversityProblem Specification1. Pre-Analysis & Start-Up2. Geometry3. Mesh4. Setup (Physics)5. Solution6. Results7. Verification & Validation8. ExercisesSolutionSolution MethodsIn the Ou t l i n e window, select S o l u t i o n M e t h o d s to open the S o l u t i o n Me t h o d s window. Under S p a t i a l D i s c r e t i z a t i o n ,ensure that the option under F l o w S e c o n d O r d e r U p w i n d is selected.Solution ControlsIn the Ou t l i n e window, select S o l u t i o n C o n t r o l s to open the S o l u t i o n C o n t r o l s window. Ensure that the C o u r a n t N u m b e ris set to 5 . 0 .MonitorsIn the Ou t l i n e window, click M o n i t o r s to open the Mo n i t o r s window. In the Mo n i t o r s window, select R e s i d u a l s - P r i n t , P l o tand press E d i t . . . . This will open the R e s i d u a l Mo n i t o r s window. We want to change the convergence criteria for our solution.Under E q u a t i o n and to the right of C o n t i n u i t y , change the A b s o l u t e C r i t e r i a to 1e-6. Repeat for x - v e l o c i t y , y - v e l o c i t y ,and e n e r g y , then press O K. Search CornellANSYS WB - Supersonic Flow Over a Wedge - Solution - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Solution 17 / 28Solution InitializationIn the Ou t l i n e window, select S o l u t i o n I n i t i a l i z a t i o n . We need to make an "Initial Guess" to the solution so FLUENT can iterateto find the final solution. In the S o l u t i o n I n i t i a l i z a t i o n window, under C o m p u t e f r o m , select f a r f i e l d from the drop down box.Check to see that the values that generate match our inputted values, then press I n i t i a l i z eRun CalculationIn the Ou t l i n e window, select R u n C a l c u l a t i o n . Change the N u m b e r o f I t e r a t i o n s to 100. Double click C a l c u l a t e to run thecalculation. It should only take about a minute to solve. After the calculation is complete, save the project.Go to Step 6 - ResultsThis work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States LicenseAdaptavist Theme Builder (4.2.4-M1) Powered by Atlassian Confluence 3.5.16, the Enterprise WikiANSYS WB - Supersonic Flow Over a Wedge - Solution - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Solution 18 / 28Simulation > > ANSYS WB - Supersonic Flow Over a Wedge - ResultsLabels: NoneSimCafeHome Browse/Manage LoginSearchANSYS WB - Supersonic Flow Over a Wedge - ResultsAdded by Benjamin J Mullen , last edited by Benjamin J Mullen on Mar 01, 2012 22:59 Author: Benjamin Mullen, Cornell UniversityProblem Specification1. Pre-Analysis & Start-Up2. Geometry3. Mesh4. Setup (Physics)5. Solution6. Results7. Verification & Validation8. ExercisesResultsVelocity VectorsFirst, let's take a look at the velocity vectors. In the Ou t l i n e window, under R e s u l t s select C o l o r s a n d A n i m a t i o n s . In theC o l o r s a n d A n i ma t i o n s window, under Gr a p h i c s , select V e c t o r s . Then press S e t U p . . . .In the Ve c t o r s window that opens, change the S c a l e of the arrows to 0 . 2 5 , and change the C o l o r b y parameter to V e l o c i t y . . .M a c h N u m b e rHit D i s p l a y to view the vectors in the graphics windowSearch CornellANSYS WB - Supersonic Flow Over a Wedge - Results - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Results 19 / 28Once you have plotted the velocity vectors, you may close the Ve c t o r s menu.Mach Number ContoursNext, we will plot the contours of mach number. In the Gr a p h i c s a n d A n i ma t i o n s window under _Graphics, select C o n t o u r s , andpress S e t U p . . . . Change the C o n t o u r s O f parameter to V e l o c i t y . . . M a c h N u m b e r . Next, check the box next to F i l l e d .Change the L e v e l s to 5 0and press D i s p l a yNext, click on print information icon, and click anywhere behind the shock. This will display arange of values. For instance, I received (2.2354529, 2.2513809). These range of values match well with the analytic solution wereceived in the pre-anaysis (Mach no. = 2.254, 0.8% difference)Pressure Coefficient/ Static Pressure ContoursNow, change the C o n t o u r s O f parameter to P r e s s u r e . . . P r e s s u r e C o e f f i c i e n t and press D i s p l a y .ANSYS WB - Supersonic Flow Over a Wedge - Results - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Results 20 / 28Next, change the C o n t o u r s O f parameter to P r e s s u r e . . . S t a t i c P r e s s u r e and press D i s p l a y . When you have plotted thecontours of static pressure, you may close the C o n t o u r s window. Again, use the p r i n t i n f o r m a t i o n tool to view the pressurebehind the shock. I received the range (282041.19, 286057.13). The average of this range is about 2.803 atmospheres. From theanalytical solution, we found that the pressure behind the shock is about 2.824, a 0.7% difference.Pressure Coefficient Along WedgeIn the Ou t l i n e window under R e s u l t s , select P l o t s . In the P l o t s window, select X Y p l o t and press S e t U p . . . . Change the YA x i s F u n c t i o n to P r e s s u r e . . . P r e s s u r e C o e f f i c i e n t , and select the W e d g e under S u r f a c e s .To see the plot, press P l o tMeasure Shock AngleTo measure the shock angle, we first need to create a line that we can plot the coefficient of pressure over. In the S o l u t i o n X YP l o twindow, click N e w S u r f a c e > L i n e / R a k e . We will arbitrarily use the line, y = 0.35. Set the start point of the line as ( 0 , 0 . 3 5 ) , andthe end point of the line as ( 1 . 5 , 0 . 3 5 ) . Name the line y = 0 . 3 5 . Now press C r e a t eANSYS WB - Supersonic Flow Over a Wedge - Results - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Results 21 / 28Now, the new surface will appear in the list of surfaces. We want to plot the pressure coefficient across the wedge and the new linewe created in order to determine the shock angle. In the list of surfaces, select w e d g e , s y m m e t r y , and y = 0 . 3 5 . Press P l o t .We can then use the information from the plot to solve for the shock angle.The shock angle from the analytical solution was 32.221 degrees. Because we took the value from a graph, a bit more error is to beexpected.Print Drag CoefficientNext, we will have FLUENT report the drag coefficient. Close the S o l u t i o n X YP l o t window. In the Ou t l i n e window, go toR e p o r t s . In the R e p o r t s window under R e p o r t s , select F o r c e s and press S e t U p . . . . Ensure W e d g e is selected and pressP r i n t . The drag coefficient will be printed.Go to Step 7 - Verification & ValidationGo to ExercisesThis work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States LicenseAdaptavist Theme Builder (4.2.4-M1) Powered by Atlassian Confluence 3.5.16, the Enterprise WikiANSYS WB - Supersonic Flow Over a Wedge - Results - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Results 22 / 28Simulation > > ANSYS WB - Supersonic Flow Over a Wedge - Verification & ValidationLabels: NoneSimCafeHome Browse/Manage LoginSearchANSYS WB - Supersonic Flow Over a Wedge - Verification & ValidationAdded by Benjamin J Mullen , last edited by Benjamin J Mullen on Mar 07, 2012 12:30 Author: Benjamin Mullen, Cornell UniversityProblem Specification1. Pre-Analysis & Start-Up2. Geometry3. Mesh4. Setup (Physics)5. Solution6. Results7. Verification & Validation8. ExercisesVerification & ValidationVerificationAdapt the MeshIn order to test our simulation for convergence, we will refine the mesh. Refining the mesh will allow use to make sure that the resultswe are calculating are independent of the mesh. However, instead of refining the mesh everywhere (which would be wasteful, as mostof the area of the domain far away from the shock has constant values), we will use our results to refine our mesh. Specifically, we aregoing to use the gradient of the pressure to determine where to refine the mesh. First, let's take a look at our mesh. In the Ou t l i n ewi n d o w, s e l e c t G r a p h i c s a n d A n i m a t i o n s , u n d e r _ Gr a p h i c s , select M e s h , then press S e t u p . Select all of the surfaces(except y=0.35) and press D i s p l a y . This will display the current mesh.You may now close the Me s h D i s p l a y window. In the menu bar, go to Adapt > Gradient. Under Op t i o n s uncheck C o a r s e n .Under Me t h o d click the radio box next to G r a d i e n t . Ensure that G r a d i e n t s o f > P r e s s u r e . . . S t a t i c P r e s s u r e are selected.Then press C o m p u t e .Search CornellANSYS WB - Supersonic Flow Over a Wedge - Verification & Validation - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/pages/viewpage.action?pageId=170201594 23 / 28This will compute the maximum and minimum gradients of static pressure. Next, we need to pick a threshold. In order to do this, clickon C o n t o u r s . . . . This will open the familiar C o n t o u r s window. In the C o n t o u r s window, select Contours of A d a p t i o n . . .E x i s t i n g V a l u e , then press C o m p u t e . This will populate the C o n t o u r s menu with the values were were viewing for adaption, inthis case, gradient of the static pressure. Also, make sure to uncheck N o d e V a l u e s .Finally, press D i s p l a y to display the contours of static pressure gradient.Our goal is to discover the areas of high gradient, and mark those areas for adaption. Using the contour graph we can then find theareas of high pressure gradient that we want to refine. In the C o n t o u r s window, uncheck A u t o R a n g e . This will allow us to specifythe range of gradients we can see in the graph. Change the M i n value to 1 0 0 0 0 . Then press D i s p l a y . You will see that thepressure gradients above 10000 generally mark the area of high pressure gradient quite well. We will use 10000 as our threshold forrefinement.ANSYS WB - Supersonic Flow Over a Wedge - Verification & Validation - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/pages/viewpage.action?pageId=170201594 24 / 28Return to the Gr a d i e n t A d a p t i o n window, and enter 1 0 0 0 0 into R e f i n e T h r e s h o l d . Then press M a r k . The p r i n t window willinform us we have marked 70 elements for refinement. Next, press A d a p t . You will be asked if you want to change the mesh. PressY e s .It will seem like nothing has changed, but that is because we need to re-display the mesh in order to see the adaption. The new meshshould look something like this.Notice that the area surrounding the shock was refined. Now, re-initialize the solution, (Solution Initialization > Compute From Farfield> Initialize), and rerun the solution (you will also need to increase the number of iterations I recommend 150).Now, once again, plot the contours of the mach number. Below is a comparison of the mach number results from the original meshand the refined mesh.Original MeshRefined Mesh The most striking difference between the two results is the thickness of the shock. Notice that for the refined mesh, the shock is lessthick that for the original mesh. This shows that the refined mesh is converging towards the real case.Comparison to Analytical SolutionANSYS WB - Supersonic Flow Over a Wedge - Verification & Validation - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/pages/viewpage.action?pageId=170201594 25 / 28In order to verify our simulation, we need to compare our results to either an analytical solution or an experiment. Below is a tablecomparing the values from the simulation with the calculations from the pre-analysis.Mach Number Static Pressure (atm) Shock Angle (degrees)Theory Value2.254 2.824 32.22FLUENT Solution2.243 2.803 34.99Percent Difference0.8% 0.7% 8.2%As we can see from the table, we are getting fairly good matching between the computation and analytical approaches. From this wecan build our trust in our simulation.Continue to ExercisesThis work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States LicenseAdaptavist Theme Builder (4.2.4-M1) Powered by Atlassian Confluence 3.5.16, the Enterprise WikiANSYS WB - Supersonic Flow Over a Wedge - Verification & Validation - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/pages/viewpage.action?pageId=170201594 26 / 28Simulation > > ANSYS WB - Supersonic Flow Over a Wedge - ExercisesLabels: NoneSimCafeHome Browse/Manage LoginSearchANSYS WB - Supersonic Flow Over a Wedge - ExercisesAdded by Benjamin J Mullen , last edited by Benjamin J Mullen on Mar 01, 2012 17:52 Author: Benjamin Mullen, Cornell UniversityProblem Specification1. Pre-Analysis & Start-Up2. Geometry3. Mesh4. Setup (Physics)5. Solution6. Results7. Verification & Validation8. ExercisesSupersonic Flow Over a ConeChange the geometry from a wedge to a cone. What do you expect to change?In the Ou t l i n e window, click on G e n e r a l under P r o b l e mS e t u p . Under 2 D S p a c e select A x i s y m m e t r i c . We also need tochange the boundary condition for the symmetry to an axis. Click on B o u n d a r y C o n d i t i o n s in the Ou t l i n e window. In theB o u n d a r y C o n d i t i o n s window, under Z o n e , select S y m m e t r y . Change the T y p e to A x i s . Now, reinitialize the solution, then runit again for 100 iterations.Separated ShockNext, we will alter the geometry to achieve a separated shock. Close FLUENT and open the Design Modeler. We want to increasethe angle of the wedge above its critical angle. We will increase the angle to 35 degrees. Change the geometry's dimensions tomatch that of the diagram below.Once the geometry has changed, close the design modeler. We will have to re-calculate the solution, but we will want to change somefactors affecting the solution. Usually, when you make an upstream change in ANSYS, the program will update all of the downstreamdata. We want to break this connection, so right click and select R e s e t . We will have to input the boundary conditions again, but that shouldn't take long and will end up saving us time when wecalculate the solution inside of the FLUENT environment.Next, open up the mesher by double clicking. Update the mesh by clicking. Close the mesher, click Search CornellANSYS WB - Supersonic Flow Over a Wedge - Exercises - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Exercises 27 / 28, then once again double click. Re-enter all of the data from Step 5 (here is link forreference). This time, set the C o u r a n t N u m b e r to 1 . 0 . This will make the solution a little more unstable, but it will solve much, muchfaster. Run the solution again, this time with 5000 iterations.Plot the contour plot of the mach number to see how the shock has changed.This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States LicenseAdaptavist Theme Builder (4.2.4-M1) Powered by Atlassian Confluence 3.5.16, the Enterprise WikiANSYS WB - Supersonic Flow Over a Wedge - Exercises - Simulation - Confluence 06-08-2012https://confluence.cornell.edu/display/SIMULATION/ANSYS+WB+-+Supersonic+Flow+Over+a+Wedge+-+Exercises 28 / 28