“…Following [10,12], we introduce the critical velocity U c , at which the instability occurs first, and the associated supercriticality γ = U/U c . The dimensionless parameters corresponding to the instability threshold are designated by R c , β c , and λ c , while the critical wavenumber and angular velocity are m c and Ω c , respectively [12]. An increase in γ at constant λ * * , β * * , and ν leads to the variation of R, β, and λ in accordance with the relations γ = R/R c = λ c /λ = = β c /β.…”