Mitigating unwanted vibration in mechanical structures via effective and reliable approaches is an important and difficult part of the design process. For example, a good balance between ride comfort and handling for passenger vehicles, the need to build taller and more slender buildings while maintaining good dynamic performances under wind and earthquake disturbances, and the trade off between maintaining straight running stability and reducing track wear when curving for railway vehicles, have all attracted much research from both academia and industry. In the current drive for more flexible, lightweight and more efficient structures, enhancing the capability of vibration suppression systems has become even more important. The introduction of the inerter concept has from theoretical point of view fundamentally enhanced the capability of passive vibration suppression systems. Significant theoretical performance advantages for a wide range of mechanical structures have been identified. However, when working on real applications, we face the obstacle of inadequate knowledge of the dynamic properties of physical inerter realisations. This project will establish accurate fluid based inerter models and demonstrate the potential superiority of such designs for passenger cars, tall buildings and railway vehicles through case studies developed in close collaboration with industrial project partners. The proposed work will enable the widespread uptake of fluid inerter based vibration suppression design techniques and constitute a major step towards wide spread application in multiple industrial sectors including road and rail transportation, civil engineering as well as aerospace engineering. The resulting improvements in the UK's capability for advanced design will greatly assist the high-end manufacturing industry to maintain its competitive edge.

In recent years the concept of driverless or autonomous road vehicles (AVs) has gained a great deal of technical respectability and most major manufacturers intend to bring a partially or fully autonomous vehicle to market within the next few years. Much progress has been made on a range of technologies relevant to this concept, including digital mapping, position recognition by lidar and radar systems and advanced vehicle to vehicle communications. There are a number of advantages for such vehicles over normal driver controlled vehicles in terms of safety, reliability, access for the disabled and increasing the efficiency of road use. The latter comes about primarily because such vehicles are able to drive closely together in platoon formation. This project is concerned with a technical area associated with platoon running. where to date only a restricted amount of experimental work has been carried out - that of the aerodynamics of vehicles travelling in platoons, and the nature of the flow field in and around platoons is not well understood. In particular the following aspects will be investigated. a) The overall stability of vehicles travelling in the wake of other vehicles, particularly if there are organised coherent wake flow structures such as trailing vortices. These stability effects may be made more severe by the presence of slight cross winds that result in asymmetric and variable wakes, which can be expected to occur for the majority of the time. b) Problems associated with exhaust pollutants can also be envisaged, as it is possible that pollutants may build up along the length of the platoon and not be released into the open atmosphere, and may, if the conditions are suitable, be ingested by vehicle power plant and ventilation systems. c) Aerodynamic noise is an important design consideration for road vehicles, both in terms of passenger and driver comfort, and in terms of the overall effect of traffic on the surrounding environment. It is not clear how the use of platoon running of AVs will affect the internal and external propagation of aerodynamic vehicle noise. In addition work is proposed to investigate a related problem - the aerodynamic aspects of trains running very closely together, an issue which has emerged from recent studies of high speed coupling and uncoupling operations. This work will be carried out through physical and computational modelling. The physical modelling work will utilise the University of Birmingham moving model TRAIN Rig, which allows individual and platoons of vehicles to be propelled along a 150m long test track at speeds of up to 80m/s. The work will involve detailed measurements of pressure over the vehicles (such that aerodynamic forces can be calculated), and measurements of aerodynamic noise propagation from platoons and pollutant dispersion from platoons. The computational work will be carried out using conventional RANS techniques for a wide range of vehicle and platoon configurations, but also a smaller number of calculations using more sophisticated DES and LED methods to provide high quality unsteady flow information. Taken together, the physical modelling results and the CFD will enable a detailed understanding to be achieved of the aerodynamic behaviour of ground vehicles running closely together, which will be of considerable interest and importance to a variety of stakeholders.