We consider a meniscus between rotating and nonrotating species in the Bose-Einstein condensate (BEC) with repulsive inter-atomic interactions, confined to a pipe-shaped trap. In this setting, we derive a system of coupled one-dimensional (1D) nonpolynomial Schrödinger equations (NPSEs) for two mean-field wave functions. Using these equations, we analyze the phase separation/mixing in the pipe with periodic axial boundary conditions, i.e. in a toroidal configuration. We find that the onset of the mixing, in the form of suction, i.e., filling the empty core in the vortical component by its nonrotating counterpart, crucially depends on the vorticity of the first component, and on the strengths of the inter-atomic interactions.PACS numbers: 03.75.Lm, Since the creation of vortices in Bose-Einstein condensates (BECs) [1,2], this topic has been a subject of many experimental and theoretical works, as reviewed in Refs.[3]. In particular, much attention has been drawn to vortices in mixtures of two BEC species; in fact, the first vortices were created in a two-component setting [1], and a theoretical analysis of that setting was developed too [4]. In this connection, a situation of straightforward interest is the interaction of rotating and nonrotating immiscible BEC species. It is natural to expect that the nonrotating component may fill the hollow vortical core(s) in the rotating one. As shown experimentally, vortices and vortex lattices with empty and filled cores feature a great difference in their structure [2,5]. Very recently it has been also predicted the possibility to create vortex with arbitrary topological charge by phase engineering [6].Matter-wave vortices can be created not only in largeaspect ratio settings, but also in narrow cigar-shaped traps ("pipes"), which help to stabilize them [7]. In the pipe geometry, it is interesting too to consider the interaction of rotating and nonrotating BEC species, which is the subject of the present work. In particular, a natural issue in this case is the effect of "suction", i.e., onset of effective mixing between two nominally immiscible species by pushing the nonrotating component into the empty core in the vorticity-carrying one. In other words, the suction implies indefinite stretching of the meniscus separating the immiscible species which originally fill two halves of the tube.In the mean-field approximation, the starting point of the analysis is a system of coupled Gross-Pitaevskii equations (GPEs) for macroscopic wave functions, ψ 1 and ψ 2 , of the two BEC species confined in the tight cylindrical trap. In the scaled form, the equations arewhere z is the axial coordinate, while x and y are the transverse ones. In these equations, lengths are measured in units of a (1) ⊥ = h/(m 1 Ω 1 ), the energy in units ofhΩ 1 , and time in units of 1/Ω 1 , where m 1,2 and Ω 1,2 are masses and transverse trapping frequencies of the two species, while the relative parameters in Eqs. (1) and (2) are m ≡ m 2 /m 1 and Ω ≡ Ω 2 /Ω 1 . The interaction strengths in the equations...