  We theoretically study the development of quantum turbulence from two
counter-propagating superfluids of miscible Bose-Einstein condensates by
numerically solving the coupled Gross-Pitaevskii equations. When the relative
velocity exceeds a critical value, the counter-superflow becomes unstable and
quantized vortices are nucleated, which leads to isotropic quantum turbulence
consisting of two superflows. It is shown that the binary turbulence can be
realized experimentally in a trapped system.
