Abstract
Heavy-duty dump trucks are an important source of particle emissions. When traveling on unpaved roads, they emit particles through wear and resuspension mechanisms. The particles are then dispersed by the turbulence created in the vehicle wake, leading to a deterioration of air quality in and around construction sites. A better understanding of the truck’s wake flow dynamics is therefore required to get a better knowledge of the resuspended particle dynamics. In the present work, the effects of Reynolds number, mudflap configuration, and load shape on the wake flow topology of an earthmoving dump truck are experimentally investigated in a wind tunnel study. 2D LDV measurements are conducted in the wake of a reduced-scale (1:50) dump truck. Three different velocities are studied (8, 12, and 16 m/s), corresponding to a height-based Reynolds number (Reh) ranging from 36,216 to 72,432. Additionally, three configurations of mudflaps (without a mudflap, a single long mudflap, and two mudflaps behind the wheels) and three shapes of material loading (empty dumpster, flat load, and dome-shaped overload) are considered. The results show that the presence of a long mudflap results in the formation of a large vortex in the truck’s wake, which is supposed to increase particle emissions. The shape of the load also plays a key role. The dome-shaped overload increases the size of the vortices and the upward backflow that develop in the close wake of the vehicle, thus enhancing particle emission. Finally, a quadrant analysis of Reynolds shear stress shows that the long mudflap favors the appearance of sweep events in the upper shear layer and close to the ground, which is supposed to increase particle emissions.
