Experimental investigation of flow control for refrigerated vehicle

Abstract

The experimental investigation of flow around a refrigerated truck is a critical research topic in the field of transport aerodynamics, as it has the potential to improve the fuel efficiency and environmental performance of these vehicles. This thesis presents the results of an experimental investigation into the flow around a refrigerated truck. The experimental tests were conducted in a wind tunnel and used a simplified bluff body model and a 1:18 simplified version of a refrigerated rigid truck. The research included measurements of the surface pressures, flow velocities and time-averaged flow field analysis using various instrumentation techniques. The geometric parameters studied included a baseline model and a series of aerodynamic appendices such as a fridge unit, the fridge unit embedded in a cab roof fairing and the cab roof fairing alone. The experiments were conducted at different speeds and yaw angles to understand the effect of the flow on the aerodynamic drag experienced by the vehicle. The main objective was to assess the impact of the fridge unit on the aerodynamic performance and the flow topology around the truck. The results of the experiments showed that the flow around a refrigerated truck is complex and highly three-dimensional, with vortical structures and flow separation occurring around the cab and trailer. The flow around a simplified model allowed to validate the methodology to be used for the investigation on a more realistic model. Then, the study of a more realistic model allowed to assess the impact of the fridge unit on the overall flow field around the truck and on its aerodynamic performance. The impact was particularly visible on the front of the model, where flow patterns were highly modified by the presence of the fridge unit and various aerodynamic devices. The flow separations that occur in this area can be controlled with the use of aerodynamic devices with high benefits on the aerodynamic performance of the vehicle. When equipped with a fridge unit the aerodynamic drag of the truck is increased by 10% compared to the baseline model. However, the use of aerodynamic devices, such as embedded fridge or a cab roof fairing, allows the drag coefficient of the truck with a fridge unit to be reduced by 8% and 12.5% respectively, for zero yaw angle. The yaw angle sensitivity study results showed an increase of the overall drag coefficient as the yaw angle increased. Overall, this study provides valuable insights into the flow dynamics around a refrigerated truck, and the results can be used to study the design of passive aerodynamic devices and for CFD study correlations.

Date of Award	12 Jul 2023
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Alistair Revell (Main Supervisor), Mark Quinn (Co Supervisor) & Ben Parslew (Co Supervisor)