New scaling law predicts how wheels drive over sand
When engineers design a new aircraft, they carry out much of the initial testing not on full-sized jets but on model planes that have been scaled down to fit inside a wind tunnel. In this more manageable setting, they can study the flow of air around an aircraft under all manner of experimental conditions. Scientists can then apply scaling laws — mathematical relationships of proportionality — to extrapolate how a full-size jet would perform, based on the behavior of its miniature counterpart. Now engineers at MIT have come up with a similar scaling law to describe how objects move through sand. The scaling law can be used to predict how large trucks and cars drive through this material, based on how toy versions of those vehicles drive through an experimental sandbox containing the same grains. Ken Kamrin, associate professor of mechanical engineering at MIT, says the scaling law may enable a wide range...