  This study investigates the spatial distribution of inertial particles in
turbulent Taylor-Couette flow. Direct numerical simulations are performed using
a one-way coupled Eulerian-Lagrangian approach, with a fixed inner wall
Reynolds number of 2500 for the carrier flow, while the particle Stokes number
varies from 0.034 to 1 for the dispersed phase. We first examine the issue of
preferential concentration of particles near the outer wall region. Employing
two-dimensional (2D) Voronoi analysis, we observe a pronounced particle
clustering with increasing $St$, particularly evident in regions of low fluid
velocity. Additionally, we investigate the concentration balance equation,
inspired by the work of johnson et al.(2020), to examine particle radial
distribution. We discern the predominant sources of influence, namely biased
sampling, turbophoresis, and centrifugal effects. Across all cases, centrifugal
force emerges as the primary driver, causing particle migration towards the
outer wall. Biased sampling predominantly affects smaller inertial particles,
driving them towards the inner wall due to sampling within Taylor rolls with
inward radial velocity. Conversely, turbophoresis primarily impacts larger
inertial particles, inducing migration towards both walls where turbulent
intensity is weaker compared to the bulk. With the revealed physics, our work
provides a basis for predicting and controlling particle movement and
distribution in industrial applications.
