With the standard Discrete Phase Model (DPM), it is not possible to display locations where the particles are trapped on walls. To be able to display these locations, it is needed to enable the Erosion/Accretion option, in the Discrete Phase Model > Physical Models tab. It won’t change the calculation if no additional setup is added. But it will add the variable Discrete Phase Variable > DPM Accretion Rate availability, which allow to display the Accretion on trapping walls.