  In recent years, numerical models have become popular and powerful tools to
investigate the electromagnetic behavior of superconductors. One domain where
this advances are most necessary is the 3D modeling of the electromagnetic
behavior of superconductors. For this purpose, a benchmark problem consisting
of superconducting cube subjected to an AC magnetic field perpendicular to one
of its faces has been recently defined and successfully solved. In this work, a
situation more relevant for applications is investigated: a superconducting
parallelepiped bulk with the magnetic field parallel to two of its faces and
making an angle with the other one without and with a further constraint on the
possible directions of the current. The latter constraint can be used to model
the magnetization of a stack of high-temperature superconductor tapes, which
are electrically insulated in one direction. For the present study three
different numerical approaches are used: the Minimum Electro-Magnetic Entropy
Production (MEMEP) method, the $H$-formulation of Maxwell's equations and the
Volume Integral Method (VIM) for 3D eddy currents computation. The results in
terms of current density profiles and energy dissipation are compared, and the
differences in the two situations of unconstrained and constrained current flow
are pointed out. In addition, various technical issues related to the 3D
modeling of superconductors are discussed and information about the
computational effort required by each model is provided. This works constitutes
a concrete result of the collaborative effort taking place within the HTS
numerical modeling community and will hopefully serve as a stepping stone for
future joint investigations.
