The stability of inviscid Beltrami flow between parallel free-slip impermeable boundaries

We present a family of exact inviscid three-dimensional Beltrami flows in horizontally periodic domain lying between two parallel free-slip boundaries. Significantly, these are not stress free: the horizontal vorticity varies on each boundary. Using direct numerical simulations (employing hyperdiffusion only for stability), we find that largest-scale member is unstable and breaks down into anisotropic turbulence, with relatively large at near boundary, associated surface frontal features. conjecture all members similarly unstable. The boundaries play an important role late stages instability by constraining deformation vortex lines This study appears to be first consider boundary context.