  We present a simple simulation model for analysing magnetic and frictional
losses of magnetic nano-particles in viscous fluids subject to alternating
magnetic fields. Assuming a particle size below the single-domain limit, we use
a macrospin approach and solve the Landau-Lifshitz-Gilbert equation coupled to
the mechanical torque equation. Despite its simplicity the presented model
exhibits surprisingly rich physics and enables a detailed analysis of the
different loss processes depending on field parameters and initial arrangement
of the particle and the field. Depending on those parameters regions of
different steady states emerge: a region with dominating N\'eel relaxation and
high magnetic losses and another region region with high frictional losses at
low fields or low frequencies. The energy increases continuously even across
regime boundaries up to frequencies above the Brownian relaxation limit. At
those higher frequencies the steady state can also depend on the initial
orientation of the particle in the external field. The general behavior and
special cases and their specific absorption rates are compared and discussed.
