BMW M6 meshing

Objective: To cleanup and mesh the BMW M6 model for the CFD analysis.

Procedure: Following are the steps to complete the above objective.

Step 1: Change the element length to 1mm in mesh mode for better visualisation.

See figure 1 & 2 to see the difference.

Figure 1 Figure 2

Step 2: Cleaning up the Outer body of the model.

See figure 3 ,we have to get rid of the single con,for that we have to cut that the surface and patch a new surface as shown in figure 4.

Figure 3 Figure 4

Step 3: Fixing the side grills.

Create the triple con as shown in figure 5.Then extend the surface using the extend command as shown in figure 6.

Figure 5 Figure 6

Use the intersect command to make the triple cons so that we can delete the unwanted surface from the grill ,see figure 7 & 8.

Figure 7 Figure 8

Now delete the unwanted surfaces so that the rest of the shape look loke figure 9.

Figure 9

Now create the patch where there is a single con loop.See figure 10,11,12 & 13.

Figure 10 Figure 11 Figure 12 Figure 13

Step 4: Fixing the windows,windscreen and rear glass.

See figure 14 ,We will see tirple cons everywhere on the windows of the model.

Figure 14

To fix this we need to delete the unwanted surfaces to remove the triplle con and create the double con as shown in figure 15.

Figure 16

Do this to all the rest of the windows and windscreens so the final image would be like figure 17.

Figure 17

Step 5: Fixing the BMW logo on the hood.

Figure 18 will show the BMW logo which needs to be removed for the proper cfd analysis,So after deleting the logo we have to patch the surface as shon in figure 19.

Figure 18 Figure 19

Step 6: Fixing the front side air vents.

Figure 20 will show us the front side air vents which we have to clean up.

Figure 20

Now we are going to clean up this particular part and remove all the single and triple cons from yhr geometry.

First of all we need to delete the extra surfaces on the back side of the air vents ,see figure 21 & 22 showing the before and after the sequence.

Figure 21 Figure 22

Now we will start to cleanup the geometry,first of all we will create some cuts to remove the unwanted part as shown in figure 23 & 24.

Figure 23 Figure 24

Now delete the extra part from the geometry which we have seperated using the cut command,see figure 25 & 26.

Figure 25 Figure 26

Now Patch this single con loop with a surface to create a closed surface ,which is the required criteria for the meshing.

See figure 27 & 28.

Figure 27 Figure 28

Now repeat the same procedure for the rest of the geometry to make it look like figure 29.

Figure 29

Step 7: Fixing the central half of the grill.

Figure 30 shows the central grill which needs to be cleaned up.

Figure 30

To start with lets delete all the intersecting and unneccessary surfaces that is causing a problem in the geometry,see figure 31 & 32.

Figure 31 Figure 32

Now make an intersecting point on the bottom of the grill so that a point is created to cut the extra and unrequired surface from it,so that we can create a closed geometry.See figure 33 & 34.

Figure 33 Figure 34

After the cuts ,delete the surfaces that is not required in the geometry,as shown in figure 35.

Figure 35

Now delete the back faces of the grills as shown in figure 36.

Figure 36

Now we need to delete the extra upper part of the grill.For this we have to project the line of the grey surface to the grill and then make the cuts to the whole grill so that we can the delelte the unrequired part of the grill.

In figure 37 we are projecting the grey surface line to the grills,in figure 38 we can see the projected line on the grill.

Figure 37 Figure 38

In figure 39 we can see that the cut command is used to create a seperation between the unwanted part of the grill and the rest of the grill.

Figure 39

After doing the same operation to the rest of the grills,the upper part of the grills should be deleted as shown in figure 40.

Figure 40

Now start doing patching the surfaces to cover the whole model as shown in figure 41 .

Figure 41

After patching the surface we have our central grill ready,see figure 42.

Figure 42

Step 8: Fixing the side view mirror.

Figure 43 shows that the side view mirror has a triple con which needs to be fixed ,to do tyhis we need to delete the surfaces that causing the triple con,as shown in figure 44.

Figure 43 Figure 44

Hence the side mirror view is fixed ,see figure 45.

Figure 45

Step 9: Fixing the tail light by removing the triple con.

Figure 46 shows the triple con around both the tail lights ,we can remove it by deleting the surfaces that are causing the triple con.See figure 47.

Figure 46 Figure 47

Step 10: Fixing the triple con in tires.

Figure 48 shows the triple con around the rim of the tire which means that some extra surfaces needs to be deleted.

Figure 48

Fix the triple con by deleting the surface that is causing the triple con to make it a double con as shown in figure49 & 50.

Figure 49 Figure 50

Step 11: Fix the bottom surface of the car model to make it as even as possible .

Figure 51 & 52 shows the uneven surface at the bottom of the car ,we just need to delete the unwanted surface and patch the new surface which makes the surface more even.

Figure 51 Figure 52

Using the zone cut create a clearance between the exhaust and the surface of the body of the car,as shown in figure 53.

Figure 53 Figure 54

Now patch the remaining surface in figure 54.

Now the final bottom surface will be look like figure 55.

Figure 55

Step 12: Keeping the parts of the car in a seperate folders.

Open the model browser and save the particular parts in a seperate folder as shown in figure 56 & 57.

Figure 56 Figure 57

Step 13: Set the PIDs.

Set the PIDs as shown in figure 58.

Figure 58

Step 13: Now We have come in the meshing part of the model.We will going to mesh the model according to the following parameters:

Body:- 3mm.

Lights:- 4mm

Grills:- 1mm.

Tires and rims:- 2mm.

ORVM:- 2mm.

Windows:- 2mm.

Silencer:- 3mm.

Logos:- 1mm.

Elements type :- Tria.

So according to the above parameters we have to set the length of the elements and then mesh the model aferthat,as shown in figure 59.

Figure 60

Step 14: Set the mesh parameters and the quality criteria as shown in figure 61 & 62.

Figure 61 Figure 62

Enable the Hidden button so that we can see the errors in the mesh as shown in figure 63.

Figure 63

Now we have remove the errors in the mesh .See figure 64

Figure 64

Step 15: Create a mirror of the half of the model.

Using the Transform command we can create a symmetric copy of the first half of the model.

Click the transform button select copy option and choose symmetry.in symmetry tab choose mirror using 3 point axes option.And click OK to create a Mirror of tHE half of the car.See figure 65 & 66.

Figure 65 Figure 66

Step 16: Create a wind tunnel enclosing the car model.

Creating the wind tunnel as per the parameters mention in the video.After creating the wind tunnel create the mesh with bottom of the plane as 20 mm ,side front and rear be 50mm and top plane be 100mm.As shown in figure 67.

Figure 67

Figure 68 shows the final meshed geometry of the wind tunnel.

Figure 68

Learning objective: In this project i got to learn about removing the errors both in topological and meshed mode,which is very important for the efficient CFD analysis.

Also I got to learn about creating a symmetry which helps to lower your effort by half .If there is a symmetry going on in the model we can work on the first half of the model and other half can be replicated .

Conclusion: For CFD analysis of this model we need to create a wind tunnel around the model to create a volume mesh.