This is the third version of a series of Computational Fluid Dynamics collections. In this version, we utilize Athena++, which is an open-source finite-volume, magnetohydrodynamics code (further details in Stone et al. 2020, ApJ, 249, 4).
In this version, we simulate the Rayleigh-Taylor instability which occurs when a perturbation disturbs an unstable equilibrium such as when a more bouyant material is below a less bouyant material, with widespread applications, from the convective motions of i) boiling water, ii) in a low-mass star's outer envelope, iii) in a high-mass star's core, iv) 'salt fingering' as occurs in Earth's oceans and putatively the sub-ice south polar lake of Enceladus, and the sub-ice ocean of Jupiter's moon Europa.
We include cases of a simple sinusoidal perturbation with a wavelength set to match the box width, a wavelength four times smaller than the box width, 6.9 times smaller than the box width, and a noisy perturbation. Particularly for the noisy perturbation, the Kelvin-Helmholtz instability clearly operates, which we plan to spread awareness of in the subsequent version of CFD NFTs.
Simulations were performed on a 2013 MacBook Pro (2 GHz Quad-Core Intel Core i7; 8 GB 1600 MHz DDR3; 256 GB SSD)
v3.0.0 features 69 NFTs.
