  We show, by direct numerical simulations, that heavy inertial particles
(characterized by Stokes number $\St$) in inhomogeneously forced statistically
stationary isothermal turbulent flows cluster at the minima of mean-square
turbulent velocity. Two turbulent transport processes, turbophoresis and
turbulent diffusion together determine the spatial distribution of the
particles. If the turbulent diffusivity is assumed to scale with turbulent root
mean square velocity, as is the case for homogeneous turbulence, the
turbophoretic coefficient can be calculated. Indeed, for the above assumption,
the non-dimensional product of the turbophoretic coefficient and the rms
velocity is shown to increase with $St$ for small $St$, reach a maxima for
$St\approx 10$ and decrease as $\sim St^{-0.33}$ for large $St$.
