Abstract
This paper investigates the performance of an aerodynamic device called corner nozzles (CN) on a truck to improve its crosswind stability. The CN consists of two air-guiding plates that are attached to the base of the truck. The plates are governed by CN turning angle (α) and parameterized from 45 deg to 90 deg. Computational fluid dynamics (CFD) is used to simulate a 1/8th truck model called ground transportation system (GTS) at a Reynolds number (Re) of 1.6 × 106 and yaw angles (Ψ) = 2.5 deg–14 deg. At α = 90 deg, the rolling moment (Cr) and side force coefficients (Csf) of the GTS can be reduced by 6–8%. The CN performs better in improving the crosswind stability as Ψ increases. The CN decreases the pressure coefficient (Cp) values on both windward and leeward surfaces. The CN geometry causes the flow turning effect which increases the fluid pressure as it flows through the CN’s channel, emitting a high-pressure fluid from its outlet. Hence, increasing the overall Cp values downstream of the truck. As α increases, the reductions in Cp on side surfaces and the flow turning effect become more pronounced. It will be shown that the total Cr and Csf of the truck are affected by the Cp distributions on the windward and leeward surfaces. The CN addition affects the Cp distribution on these side surfaces and is able to reduce the total magnitude of Cr and Csf of the truck.
