  We examine the multiscaling behavior of the normal- and superfluid-velocity
structure functions in three-dimensional superfluid turbulence by using a shell
model for the three-dimensional (3D) Hall-Vinen-Bekharevich-Khalatnikov (HVBK)
equations. Our 3D-HVBK shell model is based on the Gledzer-Okhitani-Yamada
(GOY) shell model. We examine the dependence of the multiscaling exponents on
the normal-fluid fraction and the mutual-friction coefficients. Our extensive
study of the 3D-HVBK shell model shows that the multiscaling behavior of the
velocity structure functions in superfluid turbulence is more complicated than
it is in fluid turbulence.
