Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher.
Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?
Some links on this page may take you to non-federal websites. Their policies may differ from this site.
Flow around the Ahmed body is a well-recognized benchmark test case used by the computational fluid dynamics (CFD) community for model validation of automobiles. Even though the geometry of the Ahmed body is simple, the flow field around the object is complex due to flow separation and vortex shedding. In this paper, a Discrete Phase Model (DPM) based computational methodology is presented to estimate the effect of rain on aerodynamic performance and is validated with the experimental data that is available in the literature for the NACA64-210 wing section under different rain intensities. With this validated model, we have investigated the Ahmed body under low and high rain intensities for base slant angles of 25 and 35 degrees. The computed drag coefficient for the Ahmed body under rain conditions, are compared with the experimental data from aerodynamic analysis of the Ahmed body without rain, to evaluate the rain effect.
Utility trucks with boom equipment function on environmentally sensitive areas and severe terrains where off-road conditions may cause significant damage to the trucks’ mobility and their safe operation. Indeed, considerable variations of landscape elevation and dynamic changes of terrain properties lead to extensive differences in the wheel normal reactions, drastic fluctuations of the rolling resistance at each tire, and finally, substantial changes in the total resistance to motion, which includes both the tire rolling resistance and the resistance due to the truck gravity component. Additionally, lateral forces caused by truck inclinations can lead to instability in motion, too. As a result, a utility truck can become immobilized in either longitudinal or lateral direction of movement because of one or the combination of the following events – loss of longitudinal mobility due to extensive tire slippage at some/all wheels, loss of lateral mobility due to tire side skid or rollover of the truck. To eliminate the above-listed causes that can lead to the utility truck immobilization, this study suggests a novel approach to managing the input/output factors that influence both longitudinal and lateral forces of the utility truck. In fact, the 3D morphing of the boom equipment is proposed as themore »
Utility trucks are the first responders in extreme climate and severe weather situations, for saving people’s lives to restoring traffic on the roads. However, such trucks can create dangerous situations on the roads, and off-road conditions, while moving, and performing tasks. Trucks equipped with large booms for reaching elevated heights can become unstable due to their geometry change, which can cause a drastic variation of the truck-boom system’s moment of inertia, and the extreme weight re-distribution among the wheels. Morphing capabilities of the utility trucks need to be investigated together with the vehicle-road forces in order to hold the vehicle safe on the roads.
In this research paper, static analysis and range of the normal reaction at the wheel of the utility truck is performed to characterize a safe working zone of the boom equipment when the truck is in the flat and titled surface. The analysis is performed for 5-degree of freedom boom equipment with revolute and translational joints in a complex constrained space given by the truck design using 3D moment and force-vector analysis. The possible morphing configuration of the boom equipment is examined in order to define static normal reactions at the wheel-road interaction.
Further, themore »