@Dalvit; @Lambrecht; @Graham; @Teo]. Casimir effects for classical and quantum fluids (specially for superfluid $^4$He) in slab geometry have been the subject of a number of experimental and theoretical works [@Krech; @Chan2; @Biswas2010; @Biswas; @Dohm2014; @Diehl2014]. In this context, Casimir force in a silicon micro-mechanical chip has also been demonstrated, opening up the possibility of tailoring the Casimir force by lithographically made components [@chip]. Since the Casimir effect is strongly affected by the confining geometry of the plates, we naturally take up the study of the Casimir force due to the confinement of quantum fluctuations in a cylindrical geometry.

Casimir effect due to confinement of quantum (vacuum) fluctuations of electromagnetic field in a hollow cylindrical tube was studied initially by DeRaad Jr. and Milton in Ref. [@Milton1981], and later on by a number of authors [@Gosdzinsky; @Milton1999; @Milton2010; @Straley; @Milton2004]. In this article, we consider a Bose-Einstein condensate confined to the cylindrical geometry, and explore the Casimir force arising from the presence of the condensate inside the cylinder. For a confined BEC, while the Bogoliubov excitations in the condensate are responsible for the quantum fluctuation part of the Casimir force, the confinement of the condensate wave function, which obeys Gross-Pitaevskii 