I was surprised to find out that material science uses up a significant amount of the compute time on the big research machines, at least here in the UK. It's both potentially lucrative research and computationally intensive. Combustion is the other big one that hasn't been mentioned but that's... Controversial.
Although probably underfunded compared to the two that you listed, cosmology is probably up there as well. Things like early universe and galaxy formation, megastructures, etc.
There's likely also some need for fusion plasma containment and other related simulations.
Based on the latest attempts to simulate (in LTSpice) Analog Devices or Texas Intruments ICs together with some common transistors, i would say that supercomputers might allow a simulation to converge in a finite amount of time.