This Week in CFD

Software and Applications

Reservoir simulation results showing two faults and streamlines. Image from Tecplot RS.

Reservoir simulation results showing two faults and streamlines. Image from Tecplot RS.

How Dangerous is CFD?

First a LinkedIn discussion then an a podcast and article on Desktop Engineering and now a commentary here on AFM [because I’m quoted in the article].

Agree or disagree: It’s dangerous to simplify FEA and make it accessible for the masses. [Note: I automatically substituted CFD for FEA. It changes nothing about the debate.]

The original author, Kenneth Wong, worded the question masterfully [IMO] to maximize the debate. Before answering, let’s dissect and defuse Kenneth’s word choices.

dangerous – Driving a car may be the most dangerous thing any of us do because it carries with it the constant threat of death, serious bodily harm, and expensive property damage. Is CFD that dangerous? I’d say no. If on the other hand Kenneth is using dangerous as a synonym for “risky” then there’s certainly always the risk that CFD will result in wrong answers. Wrong answers introduce risk into the design and manufacture of products.

simplify – One might be tempted to think that by simplify Kenneth means the reductio ad absurdum of CFD into a toy. I’m certain he means the development and deployment of CFD tools that don’t require a PhD and years of solver algorithm development experience to use. For example, I don’t have to be Mario Andretti to drive my car. Nor should I have to know what a Hessian is to run a CFD code.

masses – Whenever I read “masses” used in this context I’m reminded of the inscription on the Statue of Liberty that reads in part “Your huddled masses yearning to breath free / The wretched refuse of your teeming shore.” I’m fairly certain Kenneth isn’t comparing non-expert CFDers to “huddled masses” or “wretched refuse.” Nor do I think he believes CFD needs to be used by the random person on the street. He’s simply referring to all the engineers out there who could benefit from the use of simulation but don’t know what a Hessian is.

These three interpretations are why I don’t think it’s dangerous to simplify CFD for the masses. It is not risky to develop and deploy CFD tools that can be applied by non-analyst engineers. It’s not risky, but it’s not easy either.

Implicit in all of this is the user’s responsibility to know what they’re doing and to have sufficient knowledge of engineering fundamentals to know if the answers being computed are – if not good – not bogus. It implies an organization that’s made the appropriate investment in tools and training and validation and verification.

What do you think? Comment here or at DE or on LinkedIn.

How Far Upstream Should Simulation Be Performed?

Touching on some of the same topics as the “dangerous CFD” discussion, Tech4PD Episode 11 features a debate on exactly where and how early in the design process simulation should be introduced.

Watch the video and share your opinion.

News in Brief

Just a Rainbow in Candle Smoke

Check out this tiny little rainbow in the plume of smoke from an extinguished candle. I’m surprised this hasn’t already appeared on FY Fluid Dynamics. (source)

A tiny rainbow appears in the smoke from this extinguished candle flame.

A tiny rainbow appears in the smoke from this extinguished candle flame.

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2 Responses to This Week in CFD

  1. Nicole S says:

    Thank you for the congratulations! As for the candle, iirc, the reason I didn’t post it was because the Flow Viz Facebook group (and several other places) did it first. It stinks to be late to the party (especially more than fashionably late).

  2. John Chawner says:

    As you can tell, Nicole, I don’t mind being late – fashionable or otherwise.

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