Computational Fluid Dynamics (CFD)

…making sure it works

The cooperation with engineering company Creaform is starting to see results.  The pictures represent over 90 hours of engineering simply to set up and test our first model.  The software used for our CFD is the same used for several Formula 1 teams.  It is bleeding edge, and is run at Creaform by a engineer who earned his PhD in Computational Fluid Dynamics.

They took our design, made sure that the bodywork had a correct surface area on it, set up the ride height, correct wheel width, and optioned the Catfish to our specifications.

We asked Creaform to make this our baseline car; one that was the most “street-able” in design and would be considered our least aerodynamic.  No diffuser, no splitter, no canards, not lowered, two roll hoops and a full windscreen.

Almost every street car made generates lift without aids such as wings and air dams.  The Catfish produces downforce in its most street-able form, with a coefficient of drag that equaling the Miata.  Mission Accomplished!  In a car as light as the Catfish, the importance of aero downforce cannot be understated.

We’ve gotten quite good data from our first round of CFD, and will allow us to properly set up our “racier” versions for track testing.

Downforce tools–we’ve got a lot of tools to help increase downforce at the track, the most obvious being the windscreen delete.  Add a tonneau cover to a windshield delete, and the air becomes much cleaner over the top of the car.

Next up, splitter and diffuser.  The splitter’s job is to create a virtual vacuum at the front of the car.  A low pressure area is created below the diffuser when air is trapped by the front of the car, but is left to flow beneath the flat bottom.  High pressure at top and low pressure beneath equals downforce.  Out back the diffuser uses a vacuum-like method to suck the car down.  As the air flows beneath the car, the controlled volume of space suddenly expands.  Expanding space with the same volume of air means lower pressure.  Lower pressure pulling on the diffuser equals downforce.

Splitter & Canards

Diffuser

We still have lots and lots of track testing to find the proper balance between diffuser and splitter, which to us equals fun.  We’re hoping some of our early adopters can take up the challenge and give us their aero feedback.

Look for more pictures soon.  For more information on CFD, there’s always Wikipedia:  http://en.wikipedia.org/wiki/Drag_coefficient

5 Comments

  • Eleanor says:

    Whats up this is kind of of off topic but I was wondering if blogs
    use WYSIWYG editors or if you have to manually code with HTML.

    I’m starting a blog soon but have no coding knowledge so I wanted to get advice
    from someone with experience. Any help would be greatly appreciated!

    • Cord says:

      Most blogs now are set up for nearly anyone who can type to dive right into the process. While HTML is extremely helpful, it’s no longer necessary. WordPress is the favorite of most bloggers.

  • Timothy says:

    Very useful CFD data and hope more people can appreciate all the aero work you have done. It makes the CatFish much more desirable than the typical industry norm of no analysis.

  • onaroll says:

    I am struck by the fact that this project does not grandstand the name of the founder or partners involved. I like that anonymity, as it suggests the humility of someone more interested in the project results than the bragging rights. It also suggests a maturity not always encountered.

    • Cord says:

      Thank you, although I did name the company after myself. 🙂 It’s definitely a team effort here, and I make use of the decades of racing and fabrication knowledge of all my suppliers to help make the Catfish the best car possible. Look for more models coming out soon.

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