CFD Simulation: Set Up Your “Will It Float?”
One of my favorite Letterman bits of all time was “Will It Float?”. The premise was simple: an object would be described and Paul and Dave had to guess whether it would float. Dave believed that people could pretty reliably make the correct prediction based on intuition. Personally, I would have asked for the mass and volume of the object, but that’s probably why I’m not often invited to participate in fun games.
As many of you know, an object sinks or floats based on the mass of the water it can displace, at least if we exclude other complicating factors such as absorption or capsizing. If an object’s mass is less than the mass of the water that it “takes the place of”, it will float and vice versā. This fundamental law of buoyancy is commonly referred to as Archimedes’ Principle and was first proposed in “On Floating Bodies” by Archimedes around 250 B.C., but who’s counting?
With the recent advances in computational methods, especially those which enable predictions pertaining to open-surface multiphase flows and fluid-body interactions, it is now trivial to perform “Will It Float?” trials in silico. And to be completely honest, we don’t need a simulation in order to answer the question. One could, for example, calculate the answer on paper just by knowing the volume and mass of the object of interest as alluded to previously. Or, perhaps more simply, one could secure a small bucket and perform a physical experiment. Archimedes obviously used both. But, because it is so easy to setup the CFD experiments, and because the animations produced are so satisfying, we can’t help but give it a go.
We’ll start with a couple of easy targets that you probably have first hand experience with: an apple and a banana. What do you think? No googling.
Did you get them right? If you have any suggestions on future objects you’d like to see tested, or would like to know more about the CFD physics setup, shoot me an email or leave us a comment. Want to setup your own “Will It Float?” experiment, get in touch with us today to start your free STAR-CCM+ trial.
