The mathematics of burger flipping

What is the most effective way to grill food? Timing is everything, since only one surface is exposed to heat at a given time. Should we flip only once, or many times? We present a simple model of cooking by flipping, and some interesting observations emerge. The rate of cooking depends on the spectrum of a linear operator, and on the fixed point of a map. If the system has symmetric thermal properties, the rate of cooking becomes independent of the sequence of flips, as long as the last point to be cooked is the midpoint. After numerical optimization, the flipping intervals become roughly equal in duration as their number is increased, though the final interval is significantly longer. We find that the optimal improvement in cooking time, given an arbitrary number of flips, is about 29% over a single flip. This toy problem has some characteristics reminiscent of turbulent thermal convection, such as a uniform average interior temperature with boundary layers. (C) 2022 Elsevier B.V. All rights reserved.