Project 1 : CFD Meshing for Tesla Cyber Truck

CFD Meshing for Cyber Truck

Aim:

By reducing the errors in the model and meshing the different components with different criteria using ANSA software. The overall aim is to generate the volumetric mesh between the Cyber truck and wind tunnel.

Introduction:

Cyber truck is an upcoming battery electric light-duty truck is designed to have the utility of a truck with sports car performance. Built to be durable, versatile, capable and high-performance. The powerful drivetrain and low centre of gravity provides extraordinary traction control and torque—enabling acceleration from 0-60 mph in as little as 2.9 seconds and up to 500 miles of range.

Procedure:

Open ANSA software and input the model to the software.

Go to tools-check-geometry-enable single cons-and execute

The software will execute the different single cons present in the model.

Now in order to reduce this single on the whole model is a bitty task hence we should delete the half part and work on it, then after reducing the errors, by using the symmetry option we can reduce single cons and triple cons on the whole model

The portions the single cons are present in the regions of Body and Rim and tyres.

In order to make volumetric mesh the whole inside the car model should be one volume.

By keeping this on mind, we need to close the model to bring to one single volume.

Next I move through the Rim & tyres section where the single cons are present and analyse it and by creating a new surface the single cons are changed to double cons.

Next I work with body section in order to work on it first Isolation should be done, there are single cons are present there, by creating a new surface these single cons are converted to double cons.

Next in the Handle region since it has a opening from outside if it has been closed it will create its own volume which should not present with the main body volume. Hence it should be close and a single volume inside the car.

As soon as it closed it creates a triple cons so we can very well delete it by reduce the extra volumes create inside the volume.

After this inside a car some extra volumes present inside car so we can very well delete it and creating a new surface will with patch the surface.

Moving on in the front portion of the car at the there are some surface which are not very well aligned, hence we need to cut some surfaces and delete it and creating a new surface we can design in very well for meshing the component.

Like this by the end of topo clean up the single cons and triple cons should be diminished and should be single volume inside the car, the only single cons are present here is for joining the other half once we made a symmetry this cons will be diminished.

Before going to the meshing we should again go to tools option and check the geometry for any other single cons or triple cons are present.

The only single cons are present in the middle of the car after making symmetry option these single cons are converted into double cons.

Now before moving to the mesh option we should create a proper property Id’s (PID) for the whole car.

After creating PID we should assign the each PID with the respected body feature. The extra PID is deleted by using compress option. And only the main PID is kept for further process.

After creating PID’s, moving on to the meshing part now.

First we should do the surface mesh before moving to the volumetric mesh.

By isolating the single PID’s and giving the quality criteria and meshing parameter I can able to do each PID’s meshing by using the given mesh length.

First starting with LOGO, in quality criteria some parameters are to be included like skewness, minimum length, maximum length, quads options and should opt for FLUENT calculation mode in all off this option.

For Logo the mesh length is 1mm, so we need to measure the minimum distance in logo first so that that minimum length will be given in the quality criteria.

As per the design the minimum length in the logo is 0.41mm, so in quality criteria the minimum length given is 0.4 and maximum length given is 3mm, and in meshing parameter the target length of 1mm and Tria element type, and selecting the model of parameter and macros of 1mm.

Now by using the spot mesh visible option the mesh will be done on the LOGO.

Now due to some errors in the model there is skewness and minimum length error seen in the model this is called off elements, again go back in the topo clean-up and delete the unwanted extra surface and create a new surface.

After that come back to the mesh option again remesh the model, the error will be diminished and the off elements should be zero at the end of meshing.

Moving on to the Grills option of the same mesh length, isolating this PID, giving the model parameter and macros of 1 mm, meshing the model and check for the off elements, and this off elements should be zero and the end of the meshing.

Next moving on to the windows PID, the element length given is 2mm. here in quality criteria the minimum length given is 1mm and maximum length is 3mm, and the Tria element type should be selected.

And the off elements should be minimized by using spot mesh reconstruct option, if any off elements found after reconstruct option we can now use another option called grid move option here we will go to the off elements where it is located and the elements will be adjusted there so the nearby grid elements are adjusted and the off elements will be diminished.

Move on to next PID is Rim and Tyres and isolating it, and the element length is 2mm, in the quality criteria the minimum length is 1mm and maximum length is 5mm, and the element type is Tria should be selected.

And in the similar way rear view mirror mesh will be done.

Move on to next PID is silencer and isolating it and the element length is 3mm, in the quality criteria the minimum length is 1mm and maximum length is 5mm, and the element type is Tria should be selected.

Move on to next PID is Lights and isolating it and the element length is 4mm, in the quality criteria the minimum length is 3mm and maximum length is 5mm, and the element type is Tria should be selected.

Move on to next PID is Body and isolating it and the element length is 3mm, in the quality criteria the minimum length is 1mm and maximum length is 5mm, and the element type is Tria should be selected.

Now in this PID after meshing the body and bring back all the PID’s all together some other PID’s mesh will vanishes this is because variable mesh length between these PID’s.

These PID’s are the mesh between Body and Rear view mirror, Windows, Grill, Logo and Light section. So before meshing this we should take proper care.

Hence in order to keep both mesh all together wherever the joining between the body and the other PID’s the joining line should be disengage then only the whole meshing will generated with breaking.

Moving on now the surface mesh has been generated without any disturbances, now we can very well make the symmetric option so that the full model will topo cleaned up and meshed.

This can be done by using transform copy option in utilities bar. After selecting the transform copy option, by selecting the nodes at 3 different points the whole body will be symmetric at the centre and the body will generated.

After making the symmetric option there is single cons is present on the windows section this is because the two single cons are joined together so by using the cons paste option we can very well convert this single cons into double cons.

After this we can again very well check any single or triple cons are present in the model by using check the geometry option.

There should not be any single cons or triple cons are present in the model.

Now before going to the volumetric meshing we should generate the wind tunnel for the whole model so that we can generate the volumetric mesh between the wind tunnel and the car for the analysis purpose.

We should create some points in order to generate the wind tunnel. This can be done by using points-relative option. The standards to create this points are in front portion of the body and wind tunnel should be four times the body size,

similarly the back side is 6 times the body size and the top surface should be 3 times the body size, and the sides should be one times the body size, and the bottom side it be the tyres and the bottom surface should be joined.

Next by using these points i can very well create a new surface by using fitted or coon’s option from new faces option in topo mode.

After completing the creating the new surface around the model we can very well check this by wire frame mode.

Before giving the mesh we need to create the PID,s for the wind tunnel, like top surface, bottom surface, side surfaces, front, rear surfaces.

Now moving ahead meshing the wind tunnel giving the mesh parameters for top surfaces of 100mm mesh length and 20mm for bottom surfaces.

Again for the side surfaces by using parametric spacing option, in meshing and selecting the geometry and D start of 20mm and D end of 100mm.

By using spot mesh select option we can generate the mesh for the each surface.

Moving ahead after completing the meshing for the model BMW M6 and the wind tunnel by analysing in the wire frame all mesh are generated without any off elements we can move ahead for volumetric mesh.

In volumetric mesh define option for whole data base visible there are 7 volumes will be generated these are

Volume between car & wind tunnel

Volume inside the car

Volume of the silencer

Volume of 4 rim & tyres separately

The volume between car & wind tunnel only be selected and generate the volumetric mesh and analyse for the further analysis.

Result:

Volumetric mesh has been generated for the given geometry with the help of ANSA software

Conclusion:

In order to analysis any flow properties within the geometry we should first check all the loop holes in the geometry and should minimize it by topo clean up the geometry. After topo clean-up we should generate the surface mesh without any off element in the model. Similarly we should mesh the wind tunnel also.Tetra CFD is 3D mesh tool option which is used for the volumetric mesh to analyse the flow in the given geometry.

https://drive.google.com/file/d/12Q4dIve1upg3eF8MV5YHS8ExvnD-h6YU/view?usp=share_link

**(As the file size is high i cant upload through the file upload option here so i am giving a link to check with the detailed report and the volumetric mesh model through this link.)