= Solution
\b[TODO: user-deferred biology. The protein-specific haemoglobin displacement requested here is deferred; no species-specific numerical answer has been calculated.]
The ordinary physics is <Stokes settling velocity>. For a generic isolated rigid <sphere> of radius $a$, particle <mass density> $\rho_p$ and surrounding-fluid <mass density> $\rho_f$, balance the buoyancy-corrected body <force> against <Stokes law>:
$$
\frac{4\pi a^3}{3}(\rho_p-\rho_f)g_{\rm eff}=6\pi\eta aU,
\qquad U=\frac{2a^2(\rho_p-\rho_f)g_{\rm eff}}{9\eta}.
$$
Here $\eta$ is the <dynamic viscosity>. If the effective acceleration is approximately constant over the displacement and the terminal regime has been reached, $s=Ut$. In an actual centrifuge $g_{\rm eff}=\Omega^2r$, so a sufficiently large radial change requires integrating $dr/dt\propto r$ instead of assuming constant $U$. This generic relation does not resolve the deferred biological application.
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